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Name: _______________________________________________ B2 6 Mark Questions Date: Time: Total marks available: Total marks achieved: ______ Questions Q1. * Discuss the advantages and disadvantages of the use of GM organisms. (6) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. Q2. Mutations can occur in genes. Mutations can cause genetic disorders in humans. Phenylketonuria (PKU) is a genetic disorder caused by a gene mutation. People with PKU produce an inactive enzyme. The normal base sequence and the mutated base sequence which can cause PKU are shown below. normal base sequence ............ C T C G G C C C T............ mutated base sequence ............ C T T G G C C C T............ (i) Describe how the changes that have occurred in the mutated base sequence produce an inactive enzyme. (2) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. *(ii) Explain how the mutated base sequence will result in an inactive enzyme being produced during protein synthesis. (6) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. Q3. Bears A small number of fossil bones from a very large bear was found in South America in 1935. The bones were estimated to be about one million years old. Scientists used these bones to predict the shape and size of the bear. The diagram shows the bear and a person who is 165 cm tall. (a) (i) Estimate the height of the bear. (2) answer = . . . . . . . . . . . . . . . . . . . . . . . cm (ii) Which process occurs in animal cells that results in growth? (1) .............................................................................................................................................. (b) Explain why scientists can only make predictions about the size and shape of animals when working from fossil evidence. (3) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. * (c) Some species of bears eat leaves. Describe how the structure of a leaf is adapted for photosynthesis. (6) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. Q4. *(i) Biological washing powders contain enzymes. Explain how biological washing powders are able to remove insoluble food stains from clothing. (6) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. (ii) John washes his clothes using a biological washing powder on a 60 °C washing programme. Explain why the clothes were not washed as well as he had hoped. (2) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. Q5. Cells There are many different types of cell in the human body. (a) Complete the sentence by putting a cross ( An embryonic stem cell can ) in the box next to your answer. (1) A differentiate into any type of cell B differentiate into only one type of cell C only be obtained from embryos D only produce haploid cells (b) Describe how the structure of a red blood cell is related to its function. (3) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. (c) Describe the function of platelets. (2) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. *(d) Mitosis and meiosis are types of cell division. Compare these two types of cell division. (6) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. Q6. * The bar chart shows how the pulse rate of a person changes with three different exercises. Using the information from the bar chart and your scientific knowledge, explain the changes in pulse rate for the different exercises. (6) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. Q7. * Describe how the circulatory system transports substances around the body. (6) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. Q8. Suggest the advantages of cloning mammals, such as dogs, for use in medical research into human diseases. (3) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. Q9. Cloning In May 2011, the Food Standards Agency stated that meat and milk produced from cloned animals should be allowed to go on sale to the public. (a) (i) Describe the risks associated with cloning mammals. (3) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. *(ii) A cloned animal contains genetic information that is identical to its parent. Describe the stages in the production of a cloned mammal. (6) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. (b) (i) Fertilisation takes place during sexual reproduction to produce genetically different offspring. Complete the sentence by putting a cross ( Fertilisation occurs when ) in the box next to your answer. (1) A diploid gametes combine to produce a diploid zygote B diploid gametes combine to produce a haploid zygote C haploid gametes combine to produce a diploid zygote D haploid gametes combine to produce a haploid zygote (ii) Genetically different organisms contain different DNA codes that produce different proteins. Describe the process that takes place in the nucleus during the first stage of protein synthesis. (2) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. Q10. * Mitosis and meiosis are types of cell division. Compare these two types of cell division. (6) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. Q11. * Explain how water enters a plant and is moved to the leaf. (6) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (Total for question = 6 marks) Q12. * The diagram shows the coronary arteries surrounding a human heart. The coronary arteries deliver blood to the muscle cells in the heart. The coronary arteries can become narrowed or blocked by fatty deposits. Suggest how the narrowing of the coronary artery may affect how the heart functions and how this may affect other body cells. (6) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (Total for question = 6 marks) Q13. * Describe how the action of the mouth, oesophagus and stomach contribute to the digestion of food. (6) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. Q14. (a) The diagram shows part of the human digestive system. (a) (i) Complete the sentence by putting a cross ( The pancreas in the diagram is labelled ) in the box next to your answer. (1) A B C D (ii) Describe the function of the small intestine. (2) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. (b) An experiment was set up to find out what happens to food molecules in the small intestine. Visking tubing was used as a model for the small intestine. The diagrams show the experiment at the start and the results after 20 minutes. Explain the results of this experiment. (3) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. *(c) Describe how the action of the mouth, oesophagus and stomach contribute to the digestion of food. (6) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. (Total for Question is 12 marks) Q15. (a) Complete the sentence by putting a cross ( Food is moved through the digestive system by ) in the box next to your answer. (1) A diffusion B digestion C peristalsis D active transport (b) State two roles of bile in digestion. (2) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. *(c) Describe the roles of the enzymes involved in digestion. (6) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. (d) Explain how the structure of the villi allows efficient absorption in the small intestine. (3) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. (Total for Question is 12 marks) Q16. (a) Describe how a section of DNA determines the structure of a protein. (4) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. *(b) Describe the structure of DNA, including the roles of the scientists involved in its discovery. (6) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. Human DNA was sequenced during the Human Genome Project. (c) Explain how the Human Genome Project has contributed to advances in medicine. (2) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. (Total for Question is 12 marks) Q17. Heart disease can significantly reduce cardiac output. (i) Complete the sentence by putting a cross ( ) in the box next to your answer. Cardiac output is the volume of blood leaving the (1) A atrium every heart beat B atrium every minute C ventricle every heart beat D ventricle every minute *(ii) A reduced cardiac output would affect the performance of an athlete. Explain the effects that a reduced cardiac output would have on the muscle cells of an athlete. (6) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. Q18. Enzymes and digestion (a) (i) The diagram shows an enzyme and four substrates. Draw one straight line from the enzyme to its correct substrate. (1) (ii) The diagram models one way enzymes are thought to work with their substrates. Complete the sentence by putting a cross ( ) in the box next to your answer. This model represents the hypothesis known as (1) A base pairing B DNA replication C lock and key D protein synthesis (b) Some babies have difficulty absorbing nutrients from their food. Protease enzymes can be added to baby food during its manufacture. (i) Explain why protease enzymes are added to baby food. (2) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (ii) A baby food is manufactured at 35 °C. Higher temperatures affect the protease enzymes in baby food. Explain how enzymes are affected by temperatures above 40 °C. (2) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. *(c) Describe the action of carbohydrase and lipase enzymes in different parts of the digestive system. (6) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (Total for question = 12 marks) Q19. * Explain the action of enzymes in terms of the lock and key hypothesis. You may use labelled diagrams to illustrate your answer. (6) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. Q20. Enzymes In the cells of our body, enzymes speed up chemical reactions that would otherwise take place too slowly to keep us alive. (a) Draw one straight line from the enzyme to its substrate. (1) (b) What is an enzyme? (1) .............................................................................................................................................. .............................................................................................................................................. (c) Describe a factor that affects enzyme action. (2) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. *(d) (i) Biological washing powders contain enzymes. Explain how biological washing powders are able to remove insoluble food stains from clothing. (6) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. (ii) John washes his clothes using a biological washing powder on a 60 °C washing programme. Explain why the clothes were not washed as well as he had hoped. (2) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. Q21. Enzymes (a) Complete the sentences by putting a cross ( (i) Enzymes are ) in the box next to your answer. (1) A cells B hormones C proteins D sugars (ii) An enzyme is a biological catalyst that (1) A slows down all chemical reactions B speeds up a chemical reaction C prevents all chemical reactions taking place D has no effect on a chemical reaction (b) The diagrams show two sequences of six amino acids. Sequence 1 is found in an enzyme called catalase. Sequence 2 is found in an enzyme called amylase. (i) Suggest how the structures of the enzymes, catalase and amylase, are different from each other. (2) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. (ii) Suggest why the action of these two enzymes will be different. (2) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. *(c) A student carried out an investigation to study the effect of pH on the activity of catalase. In the presence of catalase, hydrogen peroxide breaks down to release oxygen gas. The student set up five test tubes, as shown in the diagram, and observed the amount of oxygen gas released. Explain the effect of pH on the enzyme catalase in this investigation. (6) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. Q22. Enzymes DNA and RNA are involved in the synthesis of proteins such as enzymes. (a) Protein synthesis involves transcription and translation. Which row shows the molecules involved in both transcription and translation? Place a cross ( ) in the box next to your answer. (1) (b) Describe what happens to the molecule produced by transcription before it is translated. (2) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (c) Explain how the lock and key hypothesis models how enzymes work. You may use labelled diagrams in your answer. (3) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. *(d) Describe how named factors affect the rate of enzyme-catalysed reactions. (6) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (Total for question = 12 marks) Q23. * The diagram shows some limbs of modern-day animals. Explain how the study of the limbs of different species of vertebrates provides evidence for evolution. (6) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. Q24. The graph shows the effect of exercise intensity on the volume of blood leaving the heart per beat. (a) (i) Complete the sentence by putting a cross ( ) in the box next to your answer. The difference between the volume of blood leaving the heart at rest and the volume of blood leaving the heart at maximum exercise intensity is (1) A 70 cm3 B 80 cm3 C 90 cm3 D 150 cm3 (ii) Using information in the graph, describe the effect of different levels of exercise intensity on the volume of blood leaving the heart. (2) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. (iii) Explain why it is important to have a change in blood flow to muscles during exercise. (3) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. *(b) The diagram shows a heart. Explain how the structures of the heart are related to their function. (6) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. (Total for Question is 12 marks) Q25. Exercise, oxygen and heart rate Pearl is training for the London marathon. Marathon runners mainly use aerobic respiration. Complete the sentence by putting a cross ( ) in the box next to your answer. (a) (i) The products of aerobic respiration are (1) A carbon dioxide and energy B lactic acid and energy C carbon dioxide and water D water and energy (ii) Aerobic respiration requires red blood cells. Explain how one structure of red blood cells relates to its function. (2) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. (b) Pearl measures her heart rate during three different types of exercise. before exercise swimming cycling (pulse rate in beats 69 73 per minute) after exercise (pulse rate in beats per 98 110 minute) Explain why the exercises have different effects on her pulse rate. sprinting 69 149 (3) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. *(c) The diagram shows the volume of oxygen the body consumed during exercise. It also shows the EPOC (excess post-exercise oxygen consumption) during recovery. Use the diagram to help to explain why these changes in oxygen consumption occur during exercise and recovery. (6) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. Q26. Fit and healthy When we exercise, our muscle cells need more energy. The diagram shows the movement of gases into and out of muscle cells. (a) (i) Give the name of gas Y. (1) .............................................................................................................................................. .............................................................................................................................................. (ii) Complete the sentence by putting a cross ( ) in the box next to your answer. Muscle cells produce a large amount of carbon dioxide during exercise. Carbon dioxide moves out of muscle cells and into the blood by (1) A diffusion B osmosis C respiration D transpiration (iii) Explain how gas Y moves into the muscle cells. (2) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. (b) Explain why a person continues to breathe at a faster rate than usual after they stop exercising. (2) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. *(c) The bar chart shows how the pulse rate of a person changes with three different exercises. Using the information from the bar chart and your scientific knowledge, explain the changes in pulse rate for the different exercises. (6) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. Q27. * The diagram shows some of the stages that occur in the formation of a human fetus. Using the diagram and your own knowledge, describe the processes that take place in the formation of the fetus from a sperm cell and an egg cell. (6) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. Q28. In 2011, South Korean scientists genetically engineered a cell from a beagle. They then cloned this cell to create a beagle. They called this beagle Tegon. Tegon glows in the dark when UV light is shone on him. Cloning involves cells that divide by mitosis. (a) Complete the sentence by putting a cross ( ) in the box next to your answer. When a cell divides by mitosis it produces (1) A two cells that are genetically different B two cells that are genetically identical C four cells that are genetically different D four cells that are genetically identical (b) To genetically engineer the original cell so that it would glow, the scientists had to obtain a suitable gene. (i) Describe the stages that a scientist would complete to obtain this gene. (2) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. *(ii) Describe the stages used in the laboratory to clone and produce Tegon from the genetically engineered cell. (6) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. Q29. Maize is a crop plant that has been genetically modified. (a) Suggest how maize is genetically modified. (2) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. (b) The graph shows how the percentage of farmland used to grow genetically modified (GM) maize has changed from 1996 to 2008. (i) Calculate the change in the percentage of farmland used to grow GM maize from 2004 to 2008. (2) answer =. . . . . . . . . . . . . . . . . . . (ii) Describe the changes in the percentage of farmland used to grow GM maize between 1996 to 2008. (2) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. *(c) Discuss the advantages and disadvantages of the use of GM organisms. (6) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. (Total for Question = 12 marks) Mark Scheme Q1. QWC * Indicative Content A discussion including some of the following points in a logical sequence Advantages reference to GM crops named GM characteristic e.g. herbicide resistance/longer shelf life/faster growth increased yield less use of chemical pesticides less harm to living things ref to beta carotene/golden rice reduction in vitamin A deficiency/improvem ent in healthreference to GM bacteria rapid population growth increased yield (of product) named GM characteristic e.g. insulin production no animals Mark (6) Level 1 0 1-2 harmed/used in production less side effects (than bovine insulin) suitable for use by vegans (no animal products) reference to GM animals production of hormones / named GM productDisadvantag es reference to crosspollination/gene transfer production of superweeds/plants with GM characteristics greater competition between plant species reduction in biodiversity/nontarget organisms harmed/ negative impact on food chains long term effects on human health unknown/side effects/allergies expensive to produce/buy reliance on GM companies (for GM seeds) farmers cannot afford to buy them risks in culturing microorganisms No rewardable content a limited discussion including one advantage OR one disadvantage e.g bacteria can produce insulin or genes can transfer to other plants the answer communicates ideas using simple language and uses limited scientific terminology spelling, punctuation and grammar are used with limited accuracy 2 3-4 a simple discussion including at least one advantage and one disadvantage OR two advantages OR two disadvantages the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately spelling, punctuation and grammar are used with some accuracy 3 5-6 a detailed discussion including at least two advantages and two disadvantages the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately spelling, punctuation and grammar are used with few errors Q2. Question Number (i) Answer Acceptable answers Mark Indicative Content (2) Mark A description including any two from the following points • change in a base from C to T (1) • (causes) change in one codon/triplet of bases (1) • results in a different amino acid (1) Question Number QWC (ii) Level 1 0 1-2 2 3-4 An explanation linking some of the following points • enzymes are proteins • mutation in DNA will result in different mRNA stran • during transcription • mRNA leaves the nucleus through the nuclear pore • the attachment of mRNA at the ribosomes • involvement of tRNA and amino acids • at the ribosome • which is translation • amino acid chain/peptide sequence altered • different protein formed/protein not (6) folded correctly No rewardable material • an attempt is made to link the change in the base sequence to the generation of a different amino acid • the answer communicates ideas using simple language and uses limited scientific terminology • spelling, punctuation and grammar are used with limited accuracy • there is evidence that the mutation is linked to a change in the protein • there may be an attempt to explain transcription of the incorrect code and translation of this although this explanation is likey to be unclear and may have missing steps • the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately 3 5-6 • spelling, punctuation and grammar are used with some accuracy • the response is likely to indicate the type of mutation and link this to a change of codon/protein • the response will show good evidence of understanding that an incorrect mRNA molecule is formed and translation by tRNA will result in an incorrect amino acid being incorporated into the protein chain • the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately • spelling, punctuation and grammar are used with few errors Q3. Answer Acceptable answers (165) × 2 (1) 330 (cm) (1) a range from 1.8 to 2.2 Accept a height value between 297 – 363 (cm) with no working shown (2) Mark (a)(i) (2) (a)(ii) (b) QWC mitosis/cell division/cell differentiation An explanation linking any three of the following points many fossils found are only part of an animal or plant (1) soft tissue has decayed(1) fossils are often broken (into pieces)(1) many fossils are yet to be found / fossil record incomplete (1) fossils do not always form (1) * (c) (1) (3) Indicative Content Mark An description including some of the following points leaves have a large surface area contain (many) chloroplasts/chloroph yll for maximum absorption of light waxy cuticle to reduce water loss stomata/pores gas exchange/to take in carbon dioxide and release oxygen guard cells that control size of stoma xylem vessels throughout the leaf deliver water and (6) mineral ions Level 1 0 1-2 No rewardable content a limited description of the structure of a leaf that gives either one adaptation or one function not linked e.g. large surface area or takes in carbon dioxide the answer communicates ideas using simple language and uses limited scientific terminology spelling, punctuation and grammar are used with limited accuracy 2 3-4 a simple description of how leaf is adapted for photosynthesis that gives one structure linked to its function in photosynthesis/or two or more adaptations/structures not linked the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately spelling, punctuation and grammar are used with some accuracy 3 5-6 a detailed description of how leaf is adapted for photosynthesis with two or more structures related to functions of photosynthesis e.g. the role of stomata in gas exchange and the presence of xylem/vessels that deliver water the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately spelling, punctuation and grammar are used with few errors Q4. Question number *(i)QWC Indicative content Level 1 0 1-2 2 3-4 Mark (6) an explanation to include some of the following: • carbohydrates/pro teins/fats in food • carbohydrases/am ylase/enzymes digest/break down carbohydrates/starch • to glucose/maltose/sug ar • proteases/pepsin/ enzymes digest/break down proteins • to amino acids • lipases/enzymes digest/break down fats • to fatty acids and glycerol • carbohydrates/pro teins/fats are insoluble • glucose/maltose/s ugar/amino acids are soluble • (therefore) get washed away/dissolved by the water • enzymes are specific to their substrates • enzymes will work best at 40°C No rewardable material • a simple explanation of enzyme activity, linking enzymes to the breaking down of food • no linkage between types of enzymes and the food groups they act on • the name of the products of enzyme breakdown are likely to be omitted, with some reference to smaller or simpler substances • communicates ideas using simple language and little scientific terminology. Spelling, punctuation and grammar are used with little accuracy • a partial explanation of enzyme activity, linking enzymes to the breaking down of particular food groups • some linkage between at least one type of enzyme and the food group it acts on • some explanation that some products will be soluble and therefore will wash out of clothes • communicates ideas showing 3 5-6 Question number (ii) Answer an explanation linking the following: (enzymes have) an optimum temperature/60°C is too hot (1) (therefore) decrease in activity/rate of reaction decreases (1) some evidence of clarity and organisation and uses some scientific terminology appropriately. Spelling, punctuation and grammar are used with some accuracy • a clear explanation of the key processes involved in enzyme activity leading to the breakdown of particular food groups. This explanation may include a simple description of the lock and key hypothesis • linkage between at least two types of enzymes and the food groups they act on • there is mention of at least two of the products of enzyme breakdown of food groups • communicates ideas clearly and uses scientific terminology appropriately. Spelling, punctuation and grammar are used with few errors Acceptable answers Mark work best at 37/37.4°C denaturing occurs (2) Q5. Answer (a) (b) (c) QWC Acceptable answers A differentiate into any type of cell Any two structures from the list with at least one matched adaptation: Structures (maximum of 2) biconcave shape (1) no nucleus (1) thin membrane (1) flexible / small (1) contains haemoglobin (1)(matched) adaptation (maximum of 2) large surface area / increase oxygen uptake (1) to increase amount of haemoglobin / oxygen-carrying capacity (1) so short distance for diffusion (1) to get through capillaries (1) to bind oxygen (1) A description including two of the following points clotting / to seal a wound / scab formed (1) stop bleeding (1) prevent infection / entry of microbes (1) fibrin (1) * (d) Mark (1) (3) (2) Indicative Content A comparison between mitosis and meiosis including Mitosis (genetically) identical cells Mark (6) Level 1 0 1-2 produced two daughter cells one division diploid daughter cells identical set of chromosomes occurs in the formation of body cells for growth and repair (of body tissues)Meiosis (genetically) nonidentical cells four daughter cells 2 divisions haploid daughter cells half the number of chromosomes occurs in the formation of gametes for sexual reproduction results in genetic variation No rewardable content a limited description including two points on either meiosis or mitosis there maybe confusion between the two but this does not negate the level the answer communicates ideas using simple language and uses limited scientific terminology spelling, punctuation and grammar are used with limited accuracy 2 3-4 a simple description including one comparison of meiosis and mitosis or a detailed description of either mitosis or meiosis the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately spelling, punctuation and grammar are used with some accuracy 3 5-6 a detailed comparison of both meiosis and mitosis – at least two correct comparisons made the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately spelling, punctuation and grammar are used with few errors Q6. Question number *QWC Indicative content Level 1 0 1-2 2 3-4 Mark (6) an explanation to include some of the following: • exercise/named exercise increases pulse rate • the more intense the exercise the greater the increase • by x beats per min (must be read off the graph for correct exercise), eg (for jogging) by 40 beats per min • whereas (named exercise, eg walking) increases pulse rate by 25 beats per min • this is an increase of 15 beats per min (eg when comparing jogging to walking) • more strenuous exercise/named strenuous exercise requires more energy • more oxygen • more glucose • to muscles • to carry out (aerobic) respiration • heart beats faster • blood flow increases (to muscles)/gets faster Do not accept references to anaerobic respiration No rewardable material • a limited explanation of the effects of exercise on heart rate • some attempt to use information from the bar chart to compare pulse rates before and after exercise • little or no attempt to explain the physiological effects of increased pulse rate in terms of either oxygen or glucose supply to the muscles • communicates ideas using simple language and little scientific terminology. Spelling, punctuation and grammar are used with little accuracy • an incomplete explanation of how exercise affects pulse rate • an understanding that increased exercise leads to increased pulse rates • a correct reference to pulse rate increasing for at least 3 5-6 one of the exercises but unlikely to be a comparison between this and another exercise • some attempt to explain the physiological effects of increased pulse rate in terms of either oxygen or glucose supply to the muscles • communicates ideas showing some evidence of clarity and organisation and uses some scientific terminology appropriately. Spelling, punctuation and grammar are used with some accuracy • a clear explanation of the effect of exercise on pulse rate • correctly states by how much pulse rate changes for at least two exercises and there is a clear comparison of correct data for at least two of the exercises • a clear explanation of the physiological reasons why pulse rate changes with exercise, referring to oxygen and glucose supply to the muscles • communicates ideas clearly and uses scientific terminology appropriately. Spelling, punctuation and grammar are used with few errors Q7. Indicative Content QWC Level 1 * 0 1-2 Mark A description including some of the following points in a logical sequence heart / ventricle pumps blood through blood vessels/arteries/vein s/capillaries to lungs and to the rest of the body arteries/named arteries transport blood away from heart veins / named veins transport blood to the heart valves prevent backflow capillaries exchange materials/named material with tissues/cells red blood cells carry oxygen plasma transports nutrients/waste/horm (6) ones No rewardable content A limited description of one structure OR one function of the circulatory system e.g. the heart pumps blood or the blood carries oxygen the answer communicates ideas using simple language and uses limited scientific terminology spelling, punctuation and grammar are used with limited accuracy 2 3-4 A simple description of two structures and their functions of the circulatory system e.g. arteries carry blood away from the heart and red blood cells transport oxygen. the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately spelling, punctuation and grammar are used with some accuracy 3 5-6 A detailed description of at least three structures and their functions of the circulatory system which MUST include relevant information on red blood cells OR plasma OR the exchange of material at capillaries. the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately spelling, punctuation and grammar are used with few errors Q8. Q9. Answer (a)(i) A description including three the following points: (cloned animals) tend to be larger at birth / body organs /named organ enlarged (1) embryo rejected/fails to develop normally/many cloned mammals failed to develop (1) (cloned animals) early death /speeds up aging (1) narrowing of the gene pool / less (genetic) variation (1) genetic disorders / defects (1) susceptible to same diseases / pathogen (1) QWC Level 1 * (a)(ii) 0 1-2 Acceptable answers Mark Ignore answers related to the meat/food product /ethics (3) Indicative Content Mark A description including use of body cell nucleus removed from body / parent cell use of egg cell nucleus removed from egg cell/enucleated egg nucleus (from body cell) transferred to enucleated egg electric shock; to stimulate cell division mitosis formation of embryo; embryo implanted (6) into surrogate No rewardable content Limited description of 2 of the stages involved in cloning and the sequence of events is confused the answer communicates ideas using simple language and uses limited scientific terminology spelling, punctuation and grammar are used with limited accuracy 2 3-4 a simple description of 3 or more of the stages involved in cloning but some of the steps may be missing or out of sequence the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately spelling, punctuation and grammar are used with some accuracy 3 5-6 a detailed description of 5 or more of the stages involved in cloning but the sequence is largely in order and complete the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately spelling, punctuation and grammar are used with few errors Answer (b)(i) (b)(ii) C haploid gametes combine to produce a diploid zygote A description including two of the following transcription (1) DNA unzips (1) (formation of ) mRNA (1) complementary to / copy of DNA / DNA acts as a template (1) Acceptable answers Mark (1) (2) Q10. QWC Level 1 * 0 1-2 Indicative Content Mark A comparison between mitosis and meiosis including Mitosis (genetically) identical cells produced two daughter cells one division diploid daughter cells identical set of chromosomes occurs in the formation of body cells for growth and repair (of body tissues)Meiosis (genetically) nonidentical cells four daughter cells 2 divisions haploid daughter cells half the number of chromosomes occurs in the formation of gametes for sexual reproduction results in genetic (6) variation No rewardable content a limited description including two points on either meiosis or mitosis there maybe confusion between the two but this does not negate the level the answer communicates ideas using simple language and uses limited scientific terminology spelling, punctuation and grammar are used with limited accuracy 2 3-4 a simple description including one comparison of meiosis and mitosis or a detailed description of either mitosis or meiosis the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately spelling, punctuation and grammar are used with some accuracy 3 5-6 a detailed comparison of both meiosis and mitosis – at least two correct comparisons made the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately spelling, punctuation and grammar are used with few errors Q11. Q12. Q13. Indicative Content * Level 1 0 1-2 A description including some of the following points in a logical sequence mouth teeth chew food/break food down into smaller pieces increasing its surface area (and) mixes food with saliva so it can be swallowed more easily enzyme action in mouth / references to named enzymes? tongue helps to roll food into a ball/bolus (so it can be swallowed more easily) oesophagus swallowing muscular contractions/peristals is in oesophagus pushes/moves food towards the stomachstomach contraction of muscle tissue in the stomach mixes food with acid and digestive juices enzyme action in stomach / references to named enzymes? hydrochloric acid contributes to the breakdown of food No rewardable content Mark (6) a limited description which is likely to be restricted to one or two processes in one area only e.g. teeth chew food or saliva helps food to be swallowed. the answer communicates ideas using simple language and uses limited scientific terminology spelling, punctuation and grammar are used with limited accuracy 2 3-4 a simple description that describes one process in at least two areas e.g. food is chewed in the mouth and pushed down the oesophagus to the stomach. the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately spelling, punctuation and grammar are used with some accuracy 3 5-6 a detailed description that describes most of the processes in at least two areas and includes the action of enzymes in the mouth or stomach the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately spelling, punctuation and grammar are used with few errors Q14. Answer (a)(i) (a)(ii) (b) (Label) B A description including any two from the following points movement of food/ peristalsis(1) release of enzymes (1) breakdown/diges tion of food (1) absorption/diffusi on of small/soluble molecules (1) into the blood (1) An explanation including three of the following points amylase is an enzyme (1) (amylase) breaks down/digests starch (1) to maltose/sugar (1) maltose/sugar is a small/ soluble molecule (1) (and can) diffuse through the wall of the visking tubing (1) Acceptable answers (1) named digestive enzymes named nutrients absorption/diffusion of food/nutrients (2) (3) glucose for maltose/ sugar allow 'pass through' for diffusion Indicative Content *(c) Mark A description including some of the following points in a logical sequence mouth teeth chew food/break food down into smaller pieces increasing its surface area (and) mixes food with saliva so it can be swallowed more easily enzyme action in mouth / references to Mark (6) Level 1 0 1-2 named enzymes? tongue helps to roll food into a ball/bolus (so it can be swallowed more easily) oesophagus swallowing muscular contractions/peristals is in oesophagus pushes/moves food towards the stomachstomach contraction of muscle tissue in the stomach mixes food with acid and digestive juices enzyme action in stomach / references to named enzymes? hydrochloric acid contributes to the breakdown of food No rewardable content a limited description which is likely to be restricted to one or two processes in one area only e.g. teeth chew food or saliva helps food to be swallowed. the answer communicates ideas using simple language and uses limited scientific terminology spelling, punctuation and grammar are used with limited accuracy 2 3-4 a simple description that describes one process in at least two areas e.g. food is chewed in the mouth and pushed down the oesophagus to the stomach. the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately spelling, punctuation and grammar are used with some accuracy 3 5-6 a detailed description that describes most of the processes in at least two areas and includes the action of enzymes in the mouth or stomach the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately spelling, punctuation and grammar are used with few errors Q15. Answer (a) (b) C peristalsis neutralisation (of stomach acid) / raise pH (1) emulsification / break down of fats (1) QWC Acceptable answers *(c) Mark (1) Accept makes stomach / intestine contents more alkaline Accept breaks down large droplets /globules / increases surface area of fats Reject molecules broken down (2) Indicative Content Mark A description including some of the following points in a logical sequence Names of enzymes: carbohydrases named carbohydrase eg amylase proteases named protease eg pepsin lipases named lipaseGeneral points about enzyme action: breakdown of large / insoluble / named molecules into small / soluble / named molecules for absorption catalysts speeds up reactions active sites that bind to substrate idea of specificitySpecific points: carbohydrates/ starch are broken down into sugars / glucose proteins /named protein are broken down into amino acids (6) Level 1 0 1-2 fats / oils / lipids / named lipid are broken down into fatty acids /glycerol No rewardable content a limited description of enzyme action that includes at least three points the answer communicates ideas using simple language and uses limited scientific terminology spelling, punctuation and grammar are used with limited accuracy 2 3-4 a simple description of enzyme action that includes at least six points the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately spelling, punctuation and grammar are used with some accuracy 3 5-6 a detailed description of at least nine points the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately spelling, punctuation and grammar are used with few errors Answer (d) An explanation linking three of the following points (E) more /fast / maximises diffusion / absorption (1) (S) microvilli (1) (E) large surface area (1) (S) single layer of cells / one cell thick / thin walls (1) (E) small diffusion distance (1) (S) capillary network / good blood supply / capillaries inside villus (1) (E) maintains diffusion gradient (1) Acceptable answers To award all three marks at least one structure (S) and explanation (E) must be linked together. Award once, linked to any structure Ignore efficient (in stem) / easier Reject ref to cell wall Mark (3) Q16. Answer (a) QWC A description including the following linked points ref to a gene (coding for protein)(1) sequence of bases determines sequence of amino acids (1) idea of one code / triplet / codon / 3 bases (for one amino acid) (1) several amino acids make up a protein / (poly)peptide (1) transcription / detail of transcription (1) translation / detail of translation (1) *(b) Acceptable answers Mark Accept on either DNA or RNA base pairs Accept a chain of amino acids eg mRNA made eg mRNA attached to ribosome (4) Indicative Content Mark A description including some of the following points in a logical sequence Points relating to DNA structural features: two strands double helix (contains) bases A, T, C, G adenine / A paired with thymine / T guanine / G paired with cytosine / C hydrogen / H bonds joining basesContributions from Scientists: X-ray (crystallography) being used to show helical structure (6) Level 1 0 1-2 to show diameter of molecule how base pairs are arranged was shown how strands are arranged was shown modelling reference to using other people's ideas No rewardable content a limited description that includes either: at least three DNA features OR one contribution the answer communicates ideas using simple language and uses limited scientific terminology spelling, punctuation and grammar are used with limited accuracy 2 3-4 a simple description that includes at least three features of DNA and at least one contribution OR two features of DNA and two contributions. the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately spelling, punctuation and grammar are used with some accuracy 3 5-6 a detailed description of the structure of DNA that includes at least three features and two contributions. the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately spelling, punctuation and grammar are used with few errors Answer (c) An explanation to include two of the following points linked together genes / base sequence (on human chromosome) identified (1) identification of faulty / mutated genes (1) people can be Acceptable answers Accept base pair sequence gene map Accept idea that genes can be linked to disease Accept diagnosis of cancer Accept a description of gene therapy Mark (2) tested for a genetic disorder (1) ref to development of gene therapy (1) idea that appropriate /early /personalised / genomic medication / counselling can be given (1) Q17. Answer (i) Acceptable answers D – ventricle every minute (1) Indicative Content *(ii) Level 1 0 1-2 Mark Mark A description including there will less blood flow (to the muscles) because less blood leaving the heart less oxygen (reaching muscle) less glucose (reaching muscle) reduced rate of aerobic respiration less energy released less carbon dioxide removed greater rate of anaerobic respiration glucose broken down without oxygen reduced muscle contraction build up of lactic acid (in muscle cells) causing cramp / (6) fatigue No rewardable content a limited description of 2 effects of reduced cardiac output on muscle the answer communicates ideas using simple language and uses limited scientific terminology spelling, punctuation and grammar are used with limited accuracy 2 3-4 a simple description of 4 or more effects of reduced cardiac output on muscle, but some steps maybe missing or out of sequence the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately spelling, punctuation and grammar are used with some accuracy 3 5-6 a detailed description of 6 or more effects of a reduced cardiac output on muscle, with the sequence largely in order and complete the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately spelling, punctuation and grammar are used with few errors Q18. Q19. Q20. Question number (a) Answer Question number (b) Answer Acceptable answers a biological catalyst A protein that changes the rate of a reaction Mark Question number (c) Question number *(d)(i)QWC Acceptable answers Mark Only one line to be drawn from enzyme Answer a description including a pair of the following: pH (1) needs to be similar to pH inside the body (1) substrate concentration (1) as substrate concentration increases then rate increasing up to a maximum (1) temperature (1) enzyme action increases to a maximum then starts to (2) decrease (1) Indicative content an explanation to include some of the following: • carbohydrates/pro teins/fats in food • carbohydrases/am ylase/enzymes digest/break down carbohydrates/starch • to glucose/maltose/sug ar • proteases/pepsin/ enzymes digest/break down proteins • to amino acids • lipases/enzymes digest/break down fats • to fatty acids and glycerol • carbohydrates/pro teins/fats are insoluble • glucose/maltose/s ugar/amino acids are soluble • (therefore) get washed away/dissolved by (1) Mark (1) Mark (6) Level 1 0 1-2 2 3-4 3 5-6 Question number (d)(ii) Answer an explanation linking the following: (enzymes have) an optimum temperature/60°C is too hot (1) (therefore) decrease in activity/rate of reaction decreases (1) the water • enzymes are specific to their substrates • enzymes will work best at 40°C No rewardable material • a simple explanation of enzyme activity, linking enzymes to the breaking down of food • no linkage between types of enzymes and the food groups they act on • the name of the products of enzyme breakdown are likely to be omitted, with some reference to smaller or simpler substances • communicates ideas using simple language and little scientific terminology. Spelling, punctuation and grammar are used with little accuracy • a partial explanation of enzyme activity, linking enzymes to the breaking down of particular food groups • some linkage between at least one type of enzyme and the food group it acts on • some explanation that some products will be soluble and therefore will wash out of clothes • communicates ideas showing some evidence of clarity and organisation and uses some scientific terminology appropriately. Spelling, punctuation and grammar are used with some accuracy • a clear explanation of the key processes involved in enzyme activity leading to the breakdown of particular food groups. This explanation may include a simple description of the lock and key hypothesis • linkage between at least two types of enzymes and the food groups they act on • there is mention of at least two of the products of enzyme breakdown of food groups • communicates ideas clearly and uses scientific terminology appropriately. Spelling, punctuation and grammar are used with few errors Acceptable answers Mark work best at 37/37.4°C denaturing occurs (2) Q21. Answer (a)(i) (a)(ii) (b)(i) (b)(ii) C proteins B speeds up a chemical reaction Any two from the following points contain different amino acids (1) different sequence/order (of amino acids) (1) Any two from the following points different shape (enzyme/protein) work with different substrates ref to active sites/lock and key (1) QWC Level Acceptable answers * (c) 0 Mark (1) (1) State a difference in an amino acid e.g. black circle in amylase (2) named substrates enzymes are specific (2) Indicative Content Mark An explanation including some of the following points more oxygen given off at pH 7 pH 7 is the optimum pH for this enzyme reaction is faster/enzyme more active in neutral solution very little oxygen given off at pH 5 and pH 9 enzyme / catalase less active no oxygen given off at pH 1 and pH 14 no enzyme activity enzyme denatured shape of active site is changed due to strong acid / low pH/strong alkali / high pH no longer binds to hydrogen peroxide (6) / substrate No rewardable content 1 1-2 a limited description is given on the results of the investigation that covers one aspect of the results e.g. identifies best pH or recognises when a reaction has or has not taken place. the answer communicates ideas using simple language and uses limited scientific terminology spelling, punctuation and grammar are used with limited accuracy 2 3-4 a simple explanation is given on at least one aspects of the results of the investigation and links this to enzyme activity e.g. enzymes work better at pH7 as more bubbles are released or inactive at pH1 as no bubbles are released. the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately spelling, punctuation and grammar are used with some accuracy 3 5-6 a detailed explanation of how pH affects enzyme activity (linking this to number of bubbles/oxygen production) including reference to denaturation and/or shape change of enzyme/active site the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately spelling, punctuation and grammar are used with few errors Q22. Q23. Q24. Answer (a)(i) (a)(ii) (a)(iii) B 80 cm3 A description that includes two of the following: it increases from rest to low intensity (1) low to moderate intensity stays the same (1) increases from moderate (1) reference to compared figures/correct manipulation of figures (1) A explanation that includes three of the following (more) oxygen needed (1) (more) glucose needed (1) for (aerobic) respiration (1) Acceptable answers Mark (1) Accept: increases as exercise intensity increases (1) Accept: reduce muscle fatigue/cramp Accept: to reduce build up of lactic acid (1) remove carbon dioxide/waste from cells (1) (2) (3) which releases (more) energy (1) so that muscles can work for longer/harder (1) maintain body temperature (1) Indicative Content QWC Level 1 *(b) 0 1-2 Mark An explanation including some of the following points in a logical sequence two sides to prevent mixing of blood left side deals with oxygenated blood thicker wall of left ventricles pump blood to body right side deals with deoxygenated blood pumps blood to lungs muscular wall of ventricles which contract atria receive blood valves to prevent backflow correct reference to (named) exp arteries/veins No rewardable content (6) a limited explanation that links one structure to its function e.g. the right side pumps blood (to the lungs) OR the pulmonary vein takes blood into the heart. the answer communicates ideas using simple language and uses limited scientific terminology spelling, punctuation and grammar are used with limited accuracy 2 3-4 a simple explanation that links two different structures in the heart to their function e.g. right ventricle pumps blood to the lungs AND atria receive blood the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately spelling, punctuation and grammar are used with some accuracy 3 5-6 a detailed explanation that covers most of the indicative content and that includes at least three different structures linked to their function the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately spelling, punctuation and grammar are used with few errors Question number (a)(i) Question number (a)(ii) Question number (b) Question number *(c)QWC Answer Mark C Answer (1) Mark an explanation linking a pair of the following: biconcave disc shape (1) (so) bigger surface area for maximum carriage of oxygen (1) no nucleus (1) (so) contains more haemoglobin for maximum carriage of oxygen (1) Answer (2) Mark an explanation linking the following: (idea that) the higher the impact of the exercise the higher the pulse rate (1) (idea that) higher pulse rate means the heart is beating faster (1) (idea that) because there is an increased energy demand (from aerobic respiration) for (3) the high impact sport (1) Indicative content an explanation to include some of the following: • volume of oxygen consumed during exercise increases • because of increased aerobic respiration • an oxygen deficit is built up during exercise • as a result of anaerobic respiration Mark (6) 1 1-2 2 3-4 3 5-6 • during exercise breathing rate increases • oxygen absorbed more quickly/more oxygen transported in the bloodstream • aerobic respiration increases until oxygen cannot reach cells any faster • anaerobic respiration starts/increases as well as aerobic respiration • lactic acid is produced • which may cause cramp • continue to breathe heavily after race until return to resting rate • EPOC is used to process lactic acid • in liver • EPOC = the oxygen deficit whilst exercising • a limited explanation of the effect of exercise on oxygen consumption • there is some attempt to explain the physiological effects of exercise on oxygen consumption in terms of more oxygen is needed • communicates ideas using simple language and some scientific terminology. Spelling, punctuation and grammar are used with limited accuracy • a clear but incomplete explanation of the main effects of exercise on oxygen consumption • the response is likely to explain the physiological effects in terms of increased oxygen/aerobic respiration and production of lactic acid, but fails to explain the change in oxygen consumption • communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately. Spelling, punctuation and grammar are used with some accuracy • a clear explanation of the effect of exercise on oxygen consumption, oxygen deficit and EPOC • the response explains the physiological effects in terms of increased oxygen consumption, aerobic and anaerobic respiration and the removal of lactic acid • communicates ideas clearly and uses a range of scientific terminology appropriately. Spelling, punctuation and grammar are used with few errors Q26. Question number (a)(i) Question number (a)(ii) Question number (a)(iii) Question number (b) Question number *(c)QWC Answer Acceptable answers Mark oxygen/O2 Answer reject O2/O2 (1) A Answer an explanation linking the following: higher concentration of oxygen in the blood/red blood cells than in muscle cells (1) (so) moves down a concentration gradient/diffuses (1) Answer Mark (1) Acceptable answers Mark Acceptable answers (2) Mark Indicative content (2) Mark an explanation linking the following: need to take in extra oxygen (EPOC) (1) (in order) to break down lactic acid (1) an explanation to include some of the following: • exercise/named exercise increases pulse rate • the more intense the exercise the greater the increase • by x beats per min (must be read off the graph for correct exercise), eg (for jogging) by 40 beats per min • whereas (named exercise, eg walking) increases pulse rate by 25 beats per min • this is an increase of 15 beats per min (eg when comparing jogging to walking) • more strenuous exercise/named strenuous exercise requires more energy • more oxygen • more glucose • to (6) Level 1 0 1-2 2 3-4 3 5-6 muscles • to carry out (aerobic) respiration • heart beats faster • blood flow increases (to muscles)/gets faster Do not accept references to anaerobic respiration No rewardable material • a limited explanation of the effects of exercise on heart rate • some attempt to use information from the bar chart to compare pulse rates before and after exercise • little or no attempt to explain the physiological effects of increased pulse rate in terms of either oxygen or glucose supply to the muscles • communicates ideas using simple language and little scientific terminology. Spelling, punctuation and grammar are used with little accuracy • an incomplete explanation of how exercise affects pulse rate • an understanding that increased exercise leads to increased pulse rates • a correct reference to pulse rate increasing for at least one of the exercises but unlikely to be a comparison between this and another exercise • some attempt to explain the physiological effects of increased pulse rate in terms of either oxygen or glucose supply to the muscles • communicates ideas showing some evidence of clarity and organisation and uses some scientific terminology appropriately. Spelling, punctuation and grammar are used with some accuracy • a clear explanation of the effect of exercise on pulse rate • correctly states by how much pulse rate changes for at least two exercises and there is a clear comparison of correct data for at least two of the exercises • a clear explanation of the physiological reasons why pulse rate changes with exercise, referring to oxygen and glucose supply to the muscles • communicates ideas clearly and uses scientific terminology appropriately. Spelling, punctuation and grammar are used with few errors Q27. Indicative Content * Level 1 0 1-2 A description including fertilisation of egg by sperm ref to fusion of nuclei forming diploid cell ref to zygote (zygote) divides by mitosis to form identical cells several mitotic divisions growth of foetus examples of how fetus grows eg in height, mass stem cells in embryo specialisation / differentiation of (stem) cells into different cell types examples of different cell types eg neurones, skin cells development of fetus No rewardable content Mark (6) a limited description including 2 or more comments about one process the answer communicates ideas using simple language and uses limited scientific terminology spelling, punctuation and grammar are used with limited accuracy 2 3-4 a simple description including 2 or more comments on 2 processes the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately spelling, punctuation and grammar are used with some accuracy 3 5-6 a detailed description including 2 or more comments on all 3 processes the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately spelling, punctuation and grammar are used with few errors Q28. Q29. Answer (a) A suggestion including any two from: new gene / DNA located(1) inserted (into plant DNA) (1) (by) genetic engineering (1) (b)(i) (b)(ii) QWC 62 and 15 (1) 47 (%) A description including two of the following points overall increase(1) by 62 (%) (+/2)(1) relevant point mentioned from graph between 1996 and 2000(1) increases between 2000 and 2008(1) *(c) Acceptable answers any named GM characteristic e.g. pest resistant accept reference to correct GM procedure e.g. restriction enzymes / use of plasmid (1) accept DNA has been changed / modified (1) award two marks for correct bald answer Mark (2) (2) Accept relevant point mentioned from graph between 2000 and 2008 (2) Indicative Content Mark A discussion including some of the following points in a logical sequence Advantages reference to GM crops named GM characteristic e.g. herbicide resistance/longer shelf life/faster growth increased yield less use of chemical pesticides less harm to living things ref to beta carotene/golden rice reduction in vitamin A deficiency/improvem ent in (6) Level 1 0 1-2 healthreference to GM bacteria rapid population growth increased yield (of product) named GM characteristic e.g. insulin production no animals harmed/used in production less side effects (than bovine insulin) suitable for use by vegans (no animal products) reference to GM animals production of hormones / named GM productDisadvantag es reference to crosspollination/gene transfer production of superweeds/plants with GM characteristics greater competition between plant species reduction in biodiversity/nontarget organisms harmed/ negative impact on food chains long term effects on human health unknown/side effects/allergies expensive to produce/buy reliance on GM companies (for GM seeds) farmers cannot afford to buy them risks in culturing microorganisms No rewardable content a limited discussion including one advantage OR one disadvantage e.g bacteria can produce insulin or genes can transfer to other plants the answer communicates ideas using simple language and uses limited scientific terminology spelling, punctuation and grammar are used with limited accuracy 2 3-4 a simple discussion including at least one advantage and one disadvantage OR two advantages OR two disadvantages the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately spelling, punctuation and grammar are used with some accuracy 3 5-6 a detailed discussion including at least two advantages and two disadvantages the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately spelling, punctuation and grammar are used with few errors
