WJEC. Kidney. Question

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1 WJEC Kidney Question

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10 7 Examiner Arholwr yn unig (d) Humans can be affected by a condition known as multiple sclerosis (MS). In this condition T cells of the immune system attack and destroy the myelin sheath. Explain how this will affect the rate of transmission of the nerve impulse. [4] (Total 10 marks) 5. Answer one of the following questions. Any diagrams included in your answer must be fully annotated. Either, (a) Describe the mechanisms by which populations can evolve into new species. [10] Or (b) Describe and explain the changes which occur to the glomerular filtrate as it passes from the Bowman s capsule to the ureter. [10] Turn over.

11 8 Examiner Arholwr yn unig (315-01)

12 9 Examiner Arholwr yn unig (315-01) (Total 10 marks) Turn over.

13 3. (a) The drawing below shows a section through part of a kidney. 7 Examiner A... B... C... (i) Label A, B and C. [2] (ii) From which region of the kidney is this section taken? [1]... (iii) Draw an arrow to show where you would expect to find podocytes. [1] (iv) Explain how cells of the proximal convoluted tubule are adapted to carry out their function. [2] (b) The table below shows typical values for some important substances found in plasma, glomerular filtrate and urine and how much of each is reabsorbed by the kidney tubules per day. Substance Plasma Filtrate Reabsorbed Urine Water (dm 3 ) Protein (mg) Chloride (mg) Sodium (mg) Bicarbonate (mg) Glucose (mg) Urea (mg) Potassium (mg) Turn over.

14 8 Examiner (i) Name two substances that are 100 % reabsorbed. [1] (ii) Calculate the percentage of water reabsorbed. [1] (iii) Calculate the percentage of urea filtered out of plasma which is excreted in urine. [1] (c) Diagrams of the nephrons of three different mammals are shown below. X Y E E D D Z E D (315-01)

15 9 Examiner (i) Name the parts labelled D and E. [1] D... E... (ii) Describe how part D uses active transport and diffusion to create an osmotic gradient within the kidney tissues. [2] (iii) Name the process by which part E absorbs water from the surrounding tissues. [1]... (iv) Which hormone changes the water permeability of the wall of part E? [1] (v) The table shows urine concentrations in mammals from different habitats; Mammal Habitat Urine concentration (mosmol l -1 ) Domestic cat mesic 3100 Kangaroo Rat xeric* 5500 Beaver freshwater 520 * xeric habitats have limited availability of water. Use the information in the table to identify the mammals to which the nephrons in the diagram belong. [1] X... Y... Z... (vi) Describe the relationship between the mammals habitat and the length of part D in their nephrons. [1] (Total 16 marks) (315-01) Turn over.

16 6 Examiner 3. The outline diagram below shows the urinary system. A... B... C... D... E... F... (a) On the diagram of the urinary system: (i) label the structures A-F; [3] (ii) draw a nephron to show its position. [1] (315-01)

17 7 Examiner (b) X Blood flow (i) Using the diagram of a glomerulus and Bowman s capsule above state how the process of ultrafiltration takes place. [3] (ii) State three ways in which the cells labelled X on the diagram are adapted for their function. [3] Turn over.

18 8 Examiner (c) (i) Why is it necessary to excrete nitrogenous materials from the body? [1] (ii) Suggest why it is necessary to control the level of sodium chloride in the blood. [1] (Total 12 marks) 4. (a) Mendel did experiments crossing peas with different characteristics. He summarised his findings in two laws. State Mendel s first law. [2] (b) The following diagrams show the family trees of two families, A and B, representing the occurrence of colour blindness in parents and their children. The allele for full colour vision is dominant to the allele for colour blindness. A B Key: = male, colour blind = male, full colour vision = female, colour blind = female, full colour vision (i) What is meant by the term dominant allele? [1] (ii) What is the name given to the type of inheritance shown in these family trees? [1] (315-01)

19 10 Examiner 5. The diagram below shows a kidney nephron. A Branch of renal artery X C Branch of renal vein B to pelvis (a) Name the parts labelled A, B and C in the diagram. [3] A... B... C... ( )

20 11 Examiner (b) The arrows indicate three types of fluid that flow through the kidney. (i) Use the table to list four differences between blood entering the kidney and that leaving. [4] Blood entering kidney Blood leaving kidney (ii) Name the fluid leaving the kidney through X and describe its composition. [2] (c) To function efficiently the kidney must maintain a high blood pressure in the glomerulus. (i) Explain how high blood pressure is maintained in the glomerulus. [2] (ii) Suggest one situation that could cause the blood pressure in the glomeruli to fall low enough to prevent the kidneys working normally. [1] (d) Describe three ethical issues involved in the use of kidney transplants to treat kidney failure. [3] (Total 15 marks) ( ) Turn over.