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StudyPacks STUDY. KS4 SCIENCE Cells, tissues & Organs Cell Organisation This Study Pack aims to cover: 1. Diffusion in cells 2. Cell organisation. SB21 Study Packs are prepared by Qualified Teachers and Specialists and are a complete range of comprehensive compiled resources based on the UK National Curriculum covering the Primary and Secondary Frameworks including SATs and GCSE examinations. Student Name Contents Diffusion and Cell organisation Notes 2-7 Practice questions 8-15 Exam questions 16-18 Mark scheme 19-22 1 2 Diffusion in Organisms Dissolved substances have to pass through the cell membrane to get into or out of a cell. Diffusion is one of the processes that allows this to happen. Diffusion occurs when particles spread. They move from a region where they are in high concentration to a region where they are in low concentration. Diffusion happens when the particles are free to move. This is true in gases and for particles dissolved in solutions. Particles diffuse down a concentration gradient, from an area of high concentration to an area of low concentration. This is how the smell of cooking travels around the house from the kitchen, for example. Examples of diffusion Two examples of diffusion down concentration gradients location particles move from to gut digested food products gut cavity blood in capillary of villus lungs oxygen alveolar air space blood circulating around the lungs Remember, particles continue to move from a high to a low concentration while there is a concentration gradient. In the lungs, the blood will continue to take in oxygen from the alveolar air spaces provided the concentration of oxygen there is greater than in the blood. Oxygen diffuses across the alveolar walls into the blood, and the circulation takes the oxygen-rich blood away. 3 4 Cells, 5 6 Cells and tissue and organs Multicellular organisms usually contain differentiated cells, adapted for specific functions. Tissues consist of groups of similar cells. Organs contain different tissues, working together to carry out particular functions. Organ systems contain different organs. The different organ systems work together in an organism. Tissues During the development of a multicellular organism, cells differentiate so that they can carry out different functions. Differentiation is the process by which a cell becomes a specialised type of cell. A tissue is a group of specialised cells that have a similar structure and function. The table shows some examples of tissues and their functions. Types of tissues and their functions Tissue Function Muscular tissue Contracts, bringing about movement Glandular tissue Produces substances such as enzymes and hormones Epithelial tissue Covers some parts of the body Organs Organs are made of tissues. A particular organ may contain several different tissues. For example, the stomach is an organ that contains: Muscular tissue - to churn the food and other contents of the stomach Glandular tissue - to produce digestive juices including acid and enzymes Epithelial tissue - to cover the inner and outer surfaces of the stomach The stomach is one of the organs that form the digestive system. The stomach contains various tissues, and each tissue is made of a particular type of cell. In order of increasing size and complexity: cells → tissues → organ (the stomach) → organ system (the digestive system) 7 Worksheet 1 Diffusion 8 Tissue and organs worksheet 2 9 Organ systems worksheet 3 10 Cells tissues and organs 1 The diagram shows a plant cell. a Identify the structures listed. Choose the correct letter A, B, C, D or E for each structure. i nucleus ................................................................................................................................... ii (1) chloroplast ................................................................................................................................... (1) iii cell wall ................................................................................................................................... b (1) Animal cells are different from plant cells. Give the letters of the two parts that are also found in animal cells. ................................................................................................................................... c (2) What is a tissue? ................................................................................................................................... ................................................................................................................................... 2 (2) The parts of plant cells have important functions. List A contains names of cell parts. List B lists some functions of cell parts. Match each cell part to its correct function. List A List B nucleus controls entry of materials into cell (4) 11 mitochondria produce protein chloroplasts release energy ribosomes controls cell activities absorb light for photosynthesis 3 Plant and animal organs contain tissues. a Name one example of a plant tissue and describe its function. ................................................................................................................................... ................................................................................................................................... b i Name one example of an animal tissue. ................................................................................................................................... ii (2) (1) Give an example of an organ where this tissue would be found. ................................................................................................................................... (1) iii What is the function of the tissue you have named? ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... 4 (1) The diagram shows four ways in which molecules may move into and out of a cell. The dots show the concentration of molecules. a Name the cell structure that controls the movement of materials into or out of cells. ................................................................................................................................... (1) 12 b i Name the process illustrated by A and B. ................................................................................................................................... ii (1) Explain the direction of the arrows in A and B. ................................................................................................................................... ................................................................................................................................... 5 (2) The diagram shows a yeast cell. a Identify the parts labelled A and B. ................................................................................................................................... ................................................................................................................................... b (2) The cytoplasm also contains mitochondria and ribosomes. What is the function of these structures? ................................................................................................................................... ................................................................................................................................... c (2) Suggest what is found in the vacuole. ................................................................................................................................... (1) 13 6 In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate. The digestive system is a group of organs which changes food from insoluble into soluble molecules. Soluble molecules can be absorbed into the blood stream. Some food cannot be digested. Describe the functions (jobs) of the organs in the digestive system. ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... (6) Diffusion in organisms 1. Explain how oxygen and carbon dioxide diffuse into the blood in the lungs. ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... ...................................................................................................................... 4 marks 14 2. Explain how nutrients are absorbed in the blood in the small intestine? ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... ...................................................................................................................... 4 marks 15 Exam Questions Q1. (a) The diagrams show cells containing and surrounded by oxygen molecules. Oxygen can move into cells or out of cells. Into which cell, A, B, C or D, will oxygen move the fastest? Write your answer, A, B, C or D, in the box. (1) (b) Draw a ring around the correct word to complete each sentence. diffusion (i) Oxygen is taken into cells by the process of osmosis . respiration (1) breathing (ii) Cells need oxygen for photosynthesis . respiration 1) membranes (iii) The parts of cells that use up the most oxygen are the mitochondria . nuclei (1) diffusion (iv) Some cells produce oxygen in the process of photosynthesis respiration . (1) (Total 5 marks) 16 Q2. The diagram shows a cell from the lining of the lung. This cell is specialised to allow gases to pass through quickly. (a) Use words from the box to label structures A, B and C. cell membrane chloroplast cytoplasm mitochondria nucleus (3) (b) (i) Which feature of this cell allows oxygen to pass through quickly? Put a tick ( ) in the box next to your choice. It is thin. It has a large nucleus. It has many mitochondria. (1) (ii) Complete the sentence by drawing a ring around the correct answer in the box. diffusion Oxygen passes through this cell by osmosis respiration (1(Total 5 marks) Q3. The drawing shows part of a root hair cell. (a) Use words from the list to label the parts of the root hair cell. cell membrane cell wall cytoplasm nucleus vacuole (4) 17 Q4. (a) The diagram shows four ways in which molecules may move into and out of a cell. The dots show the concentration of molecules. The cell is respiring aerobically. Which arrow, A, B, C or D, represents: (i) (ii) molecules? movement of oxygen molecules; .................... movement of carbon dioxide .................... (2) (b) Name the process by which these gases move into and out of the cell. ..................................................................................................................................... (1) (c) Which arrow, A, B, C or D, represents the active uptake of sugar molecules by the cell? ..................................................................................................................................... Explain the reason for your answer. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (2) (Total 5 marks) Q5. The diagram shows a group of muscle cells from the wall of the intestine. (a) On the diagram, use words from the box to name the structures labelled A, B and C. cell membrane cell wall chloroplast cytoplasm nucleus (3) (b) How are these muscle cells adapted to release a lot of energy? ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (2) (Total 5 marks) 18 Mark scheme M1. (a) A 1 (b) (i) diffusion 1 (ii) respiration 1 (iii) mitochondria 1 (iv) photosynthesis 1 [5] M2. (a) A nucleus 1 B (cell) membrane 1 C cytoplasm 1 (b) (i) it is thin 1 (ii) diffusion 1 [5] M3. (a) (cell) wall (cell) membrane cytoplasm vacuole for 1 mark each (b) (i) 4 A (ii) B for 1 mark each 2 (c) diffusion (reject osmosis) for 1 mark 1 [7] M4. (a) (ii) (i) A B for 1 mark each 2 19 b) diffusion (reject osmosis) for one mark 1 (c) C because uptake against a concentration / diffusion gradient (reject osmosis) (if C not given, then idea of movement essential) for 1 mark each 2 [5] M5. (a) A nucleus 1 B (cell) membrane 1 C cytoplasm 1 (b) any two from: • (contain mitochondria • many (mitochondria) • respiration (occurs in mitochondria) 2 [5] Worksheet 1 Answers 1 diffusion, gas/solute, solute/gas, high, lower, random 2 a The oxygen moves along a concentration gradient from a region of high to low oxygen concentration. b Folded membranes provide an increased surface area so diffusion can take place more quickly. Worksheet 2 Answers 1 Multicellular, differentiated, specialised, function, tissue 2 a sperm – specialised cell – found individually. b kidney – organ – several tissues working together. c stomach – organ – several tissues working together. 3 Small intestine – villi and microvilli to increase SA (surface area) for the diffusion of dissolved food molecules from small intestine into the blood. Any other valid points. Lungs – many alveoli to give large surface area for exchange of oxygen and carbon dioxide. 20 Worksheet 3 Answers 1 A iii, B iv, C i, D ii. 2 An organ is a collection of several different tissues that work together to carry out a particular function in the body, e.g. heart pumps blood around the body, the stomach collects the food you eat and continues the digestive process (any two examples). An organ system is a number of organs which work together to carry out a major function in the body, e.g. the digestive system which gradually breaks down insoluble food molecules into soluble molecules which can be taken into the blood stream, and then gets rid of the waste material (any two examples). 3 Each part of the digestive system relies on the parts before it, e.g. the stomach relies on the mouth, teeth and salivary glands to deliver chunks of chewed food, the small intestine depends on the stomach to continue the process of digestion and then on the enzymes made by the pancreas to help with the digestive process. The large intestine can only deal with the remains of the food which has already been digested in the small intestine and the soluble molecules absorbed into the blood. This leaves the waste material and lots of water, so the large intestine can absorb the water and remove faeces from the body. 21 Cells and Tissue and organs Mark scheme 1 a i D ii C iii A b B and D c Group of cells – with similar function. 3 2 Nucleus – controls cell activities. Mitochondria – release energy. Chloroplasts – absorb light for photosynthesis. Ribosomes – produce protein. 4 3 a Named plant tissue, e.g. epidermal/mesophyll/xylem/phloem. Function correctly linked to chosen tissue, covers surface/photosynthesis/ transport. b i Correctly named animal tissue, e.g. muscular/glandular/epithelial. (Allow other relevant answer). ii Correct organ named, which contains named tissue, e.g. stomach. iii Correct function for named tissue, e.g. contracts to cause movement/produces enzymes/lines organ. 2 a (Cell) membrane. b i diffusion ii Molecules move from a region of higher concentration to a region of lower concentration. 1 1 a A nucleus, B cell wall. b Mitochondria – release energy/respiration. Ribosomes – produce protein. c Solution/liquid/(cell) sap or description e.g. water and sugar. 2 2 4 5 2 2 1 1 1 2 1 6 Marks awarded for this answer will be determined by the standard of the scientific response as well as the Quality of Written Communication (QWC). There are no discrete marks for the assessment of written communication but QWC will be one of the criteria used to assign the answer to an appropriate level. 5-6 There is a clear and detailed description referring to most of the key organs in the digestive system and their functions, including 5–6 points from the examples below. The answer shows almost faultless spelling, punctuation and grammar. It is coherent and in an organised, logical sequence. It contains a range of appropriate or relevant specialist terms used accurately. There is a description of at least three organs and their functions with 3–4 points from the examples below. There are some errors in spelling, punctuation and grammar. The answer has some structure and organisation. The use of specialist terms has been attempted, but not always accurately. There is a brief description of the functions of at least two organs, which has little clarity and detail, with 1– 2 points from the examples below. The spelling, punctuation and grammar are very weak. The answer is poorly organised with almost no specialist terms and/or their use demonstrating a general lack of understanding of their meaning. No relevant content. (0 marks) Examples of biology points made in response: • Glands produce digestive juices • Salivary glands • Pancreas • Digestion occurs in the stomach and small intestine • The liver produces bile • The soluble food is absorbed in the small intestine • Water is absorbed from the undigested food • In the large intestine. 3-4 1-2 0 22