[Source: Knox, et al., Biology, Mcgraw Hill, Sydney, 1994, page 65]

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Brittany McKenzie
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1 1. A study was carried out to determine the relationship between the diameter of a molecule and its movement through a membrane. The graph below shows the results of the study. High Relative ability to move through a membrane Low Molecular diameter / nm [Source: Knox, et al., Biology, Mcgraw Hill, Sydney, 1994, page 65] (a) From the information in the graph alone, describe the relationship between the diameter of a molecule and its movement through a membrane. 1

2 A second study was carried out to investigate the effect of passive protein channels on the movement of glucose into cells. The graph below shows the rate of uptake of glucose into erythrocytes by simple diffusion and facilitated diffusion. Rate of glucose uptake / 3 1 mmol cm cells hr facilitated diffusion simple diffusion External concentration of glucose / mmol dm 3 Identify the rate of glucose uptake at an external glucose concentration of 4 mmol dm 3 by (i) simple diffusion;... (ii) facilitated diffusion.... (i) Compare the effect of increasing the external glucose concentration on glucose uptake by facilitated diffusion and by simple diffusion. 2

The mitochondrion in A is from a bat pancreas cell and that in B

3 (ii) Predict, with a reason, the effect on glucose uptake by facilitated diffusion of increasing the external concentration of glucose to 30 mmol dm 3. (Total 9 marks) 2. The electron micrographs below show mitochondria in longitudinal section. The mitochondrion in A is from a bat pancreas cell and that in B is from a mouse liver cell. A. B. [Source: Tribe and Whittaker, Chloroplasts and Mitochondria, (1972), 31, pp 28 29] (a) Annotate the micrographs to show two similarities in the structure of the mitochondria. 3

4 The mitochondria differ in size. State two other differences that are visible in the mitochondria Predict, with two reasons, which of the mitochondria would have been able to produce ATP at a greater rate. (Total 7 marks) 3. (a) Distinguish between diffusion and osmosis. Explain how the properties of phospholipids help to maintain the structure of the cell surface membrane. 4

5 State the composition and the function of the plant cell wall. (Total 5 marks) 4. The electron micrograph below shows part of several pancreatic islet cells. Capillary I Storage vesicles II III 5

6 (a) Identify the structures labelled I, II and III in the micrograph above and give a role for each one. A. B. C. D. Structure Role (i) Using the letter A, identify one location on the micrograph where transcription takes place. (ii) Using the letter B, identify one location on the micrograph where chemiosmosis occurs. The large, black vesicles store products of the cells that are released into the capillaries of the pancreas. (i) Suggest what product each cell is likely to be making.... (ii) Explain how the products are transported from the site of production and released from the islet cells (Total 9 marks) 6

7 5. (a) State the typical size of (i) a bacterium;... (ii) an average eukaryotic cell.... Explain the importance of the surface area to volume ratio in limiting cell size. (Total 4 marks) 6. (a) Distinguish between the terms resolution and magnification when applied to electron microscopy. 7

8 The electron micrograph below shows part of a cell. [Source: M Turmaine, UCL] Identify the structures labelled I and II. I.... II.... State one function of the structure labelled II. (d) Deduce, with a reason, whether this cell is eukaryotic or prokaryotic. (Total 6 marks) 8

9 7. According to cell theory all cells arise from pre-existing cells. The following diagram shows the cell cycle of a eukaryotic (body) cell of a diploid organism. A B (a) Define the term diploid. Identify the parts of the cell cycle labelled A and B. A... B... State three activities that occur during part A of the cell cycle. 9

10 (d) Outline the differences in cytokinesis in animal and plant cells. (e) Explain the significance of complementary base pairing in relation to the cell cycle. (Total 10 marks) 8. (a) Define osmosis. 10

11 Outline how transport occurs across membranes by facilitated diffusion. Explain how the properties of phospholipids help to maintain the structure of cell membranes. (Total 6 marks) 9. (a) List two functions of membrane proteins Oxygen (O 2 ) moves across the membrane by diffusion. Define the term diffusion. 11

12 Potassium can move across the membrane by passive or active transport. Distinguish between active transport and facilitated diffusion of ions. (d) The hormone insulin leaves the cell by exocytosis. Describe the process of exocytosis. (Total 6 marks) 10. (a) Explain how the surface area to volume ratio influences cell sizes. 12

13 State one function for each of the following organelles. (i) Ribosomes (ii) Rough endoplasmic reticulum (iii) Golgi apparatus Compare prokaryotic and eukaryotic cells in regards to three different features. Prokaryotic Eukaryotic (Total 9 marks) 11. (a) State two processes which involve mitosis. 13

14 Explain the importance of the surface area to volume ratio as a factor limiting cell size. State one difference between the proteins produced by free ribosomes and those produced by ribosomes attached to the endoplasmic reticulum. (Total 6 marks) 12. The diagram below shows the structure of a cell. (a) State the names of I and II. I: II: 14

15 Calculate the actual length of the cell, showing your working. Answer:... State the function of the structure labelled III. (d) Deduce which type of cell is shown in the diagram, giving reasons for your answer. (Total 7 marks) 15

Include metabolism, response, homeostasis, growth, reproduction and nutrition.

Include metabolism, response, homeostasis, growth, reproduction and nutrition. Topic 2: Cells Topic 2: Cells 2.1 Cell theory Assessment statement IBO Notes Include the following. Living organisms are composed of cells. 2.1.1 Outline the cell theory. Cells are the smallest unit of