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Biology B2b Speaking & Listening Test
Proteins & Enzymes
1. What are proteins made of?
 Long chains of amino acids
2. State the main functions of proteins in the body
 Hormones
 Antibodies
 Catalysts
 Structural components of tissues such as muscles
3. Enzymes are proteins that are biological catalysts. What are catalysts?
 Catalysts are molecules that increase the rate of chemical reactions
4. Enzymes are specific shapes that can bind to certain molecules. What two factors can
change an enzyme’s shape?
 Temperature
 pH
5. What has happened to an enzyme when it changes shape?
 It is denatured
6. What do digestive enzymes do?
 They breakdown large food molecules into smaller ones
7. Where is the enzyme amylase produced and what does it do?
 Made in the:
i. Salivary glands
ii. Pancreas
iii. Small intestine
 Breaks down starch/carbs into sugars
8. Where are protease enzymes produced and what do they do?
 Made in the:
i. Stomach
ii. Small intestine
iii. Pancreas
 Breaks down protein into amino acids
9. Where are lipases produced and what do they do?
 Made in the:
i. Small intestine
ii. Pancreas
 Break down fats into glycerol & fatty acids
10. What is the chemical name for stomach acid?
 Hydrochloric acid
11. Bile is produced in the liver & stored in the gall bladder. How does bile aide in digestion?
 It neutralises the stomach contents before it enters the small intestine
 It emulsifies fats so that it’s easier for the lipase to break down the fat
Enzymes in industry & in the home
1. Name one use for enzymes in the home?
 In biological detergent
2. What enzymes are added to biological detergents?
 Proteases
 Lipases
3. What is an advantage of using biological detergent?
 They can be used at low temperatures which means it cost less electricity
 Name three industrial uses for enzymes The baby food industry – proteases
pre-digest the protein
 Food industry – carbohydrases are used to convert starch into sugar syrup
 Diet industry – isomerase is used to convert glucose syrup into fructose
syrup which is much sweeter & therefore less is needed.
 What are the pros of using industrial enzymes? They allow reactions to
happen at lower temperatures & pressures
 Less energy required
4. What are the cons of using industrial enzymes?
 They are very expensive to produce
 They denature at high temperatures
Aerobic respiration
1. What is aerobic respiration?
 It is a chemical reaction that uses glucose & oxygen to release energy
2. What is the word equation for aerobic respiration?
 Glucose + oxygen = energy + carbon dioxide + water
3. When & where does aerobic respiration take place in plants & animals?
 It takes place continuously
 In all cells
4. Where in which cell organelle does respiration occur?
 In the mitochondria
5. What are the four main uses an organism has for energy released during respiration?
 To build larger molecules from smaller ones (growth)
 To allow muscles to contract (movement)
 To maintain a constant internal temperature (in mammals & birds)
 Plants use it to build up sugars, nitrates & other nutrients into protein
6. During exercise what two changes occur to the body?
 Heart rate increases
 Breathing rate and depth increases
7. Why are these changes necessary during exercise?
 Increased depth & rate of breathing allows more oxygen to be taken in to the body

Increased heart rate allows the oxygen and glucose to be pumped to the muscle
cells quicker
 Increased blood flow also allows the carbon dioxide to be removed quickly
 This allows for faster rate of respiration and therefore more energy is released
8. How do the muscles store extra glucose?
 They store it as glycogen and convert it back to glucose during exercise
Anaerobic respiration
1. What is anaerobic respiration and when does it happen?
 Happens during periods of exercise when not enough oxygen can reach the muscles
for aerobic respiration to occur.
 It is the incomplete breakdown of glucose and produces lactic acid
2. What is the difference in energy released between aerobic & anaerobic respiration?
 Anaerobic respiration releases a lot less energy
3. What is oxygen debt?
 Occurs when the muscles still need oxygen after exercise so that the lactic acid can
be broken down
 Lactic acid broken down into carbon dioxide and water
4. What is muscle fatigue?
 It is happens when lactic acid builds up during long periods of vigorous exercise
 It stops the muscles from contracting efficiently
Cell division and inheritance
1. Where in the cell are the chromosomes found and what do they contain?
 In the nucleus & they contain the genetic information/DNA
 What is mitosis and can you describe what happens during this process? Mitosis is
the process of cell division
 During mitosis the chromosomes make copies of themselves
 The cell divides once to form 2 genetically identical daughter cells
 When does mitosis occur? During growth or when making replacement cells
2. How many pairs of chromosomes do body cells have?
 23 pairs of chromosomes
 How do gametes differ from body cells? They only have half the number of
chromosomes/a single set/only 23 single chromosomes
3. What type of cell division do cells in the reproductive organs undergo in order to form
gametes?
 Meiosis
 What happens during meiosis? The chromosomes make copies of themselves
 The cell divides twice more to form four gametes each with a single set of
chromosomes
4. What happens to gametes during fertilisation?
 1 new cell is formed
 The chromosomes from each gamete pair up.
 This cell divides by mitosis to form a baby
 What is cell differentiation? When cells become 1 type of cell designed for one
specific job
5. What are stem cells?
 These are cells that are undifferentiated. They can become any type of human cell
6. Where are stem cells made?
 In human embryo
 In adult bone marrow
7. Name one condition that stem cells can treat?
 Paralysis
Genetic variation
1. What is a gene?
 A small section of DNA
2. What are alleles?
 They are different versions of the same gene. An organism gets one allele from each
parent
3. Can you explain what dominance is?
 When 1 allele controls a characteristic. Only 1 copy of the allele is needed to display
this characteristic
4. What is a recessive allele?
 An allele which only controls a characteristic when the dominant allele is missing. It
is the weaker version of the gene
5. What does it mean to be heterozygous for a condition?
 It means having 2 different alleles for the same gene
6. What does it mean to be homozygous for a condition?
 It means having 2 of the same alleles for a gene.
7. Explain the difference between genotype & phenotype
 Genotype – the combination of alleles that an organism has
 Phenotype – the characteristics an organism has based on the alleles it has (for
example, what the organism looks like)
8. What are the male and female sex chromosomes?
 Female – XX
 Male – XY
9. What do genes do?
 They code for a particular combination of amino acids which then make a specific
protein
10. What is DNA fingerprinting used for?
 It is used to identify a person from their DNA

Apart from identical twins, everyone’s DNA is unique
Genetic Disorders
1. What is polydactyly and what type of allele causes it?
 Disorder resulting in extra fingers & toes
 Caused by a dominant allele therefore only 1 parent needs to have the disorder to
pass it on
2. What is cystic fibrosis and what type of allele causes it?
 A respiratory disorder affecting the cell membranes of the lungs
 Caused by a recessive allele so it must be inherited from both parents
3. What does it mean to be a carrier of a disease?
 It means that a person can carry the disease without being affected by it
 Carriers can only happen if the disease is caused by a recessive allele.
4. What technique allows doctors to test embryos for genetic disorders?
 Embryo screening
Old & new species
1. What evidence exists showing Earth’s early life forms?
 Fossils
2. What are fossils?
 The remains of organisms from thousands of years ago, which are found in rocks
3. Describe the various ways fossils can be formed
 Formed from the hard parts of animals that don’t decay easily (shells, bones, etc.)
 Formed from parts of organisms that have not decayed because one or more of the
conditions needed for decay were absent
 Formed when parts of the organism are replaces by other materials as they decay
 Formed from preserved traces of organisms, e.g. footprints, burrows & roots
4. Why are there no fossils showing Earth’s very first life forms?
 There were most likely soft-bodied and decayed quickly.
5. What do fossils tell us about life on Earth?
 They tell us how little or how much different organisms have changed over time
6. What does extinction mean?
 It means that all members of a species are dead
7. What can cause extinction?
 Changes to the environment
 New predators arrive
 New diseases
 New, more successful competitors arrive
 Natural disasters (volcanic eruptions, asteroids, tsunamis etc.)
 The natural process of speciation
8. What is a species?
 A group of similar organisms that can reproduce to produce fertile offspring
9. What is speciation and how does it occur?
 Speciation is the development of a new species
 It occurs as a result of:
i. Geographical isolation – two populations of a species become separated
ii. Genetic variation – each population will have different combination of
alleles that make them all slightly different
iii. Natural selection – those organisms with the right alleles that help them to
survive in their environment will survive and pass these alleles onto their
offspring
iv. Speciation – the two original populations are now so different that they can
no longer interbreed. A new species has been formed