WJEC. Respiration. Questions

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1 WJEC Respiration Questions

30 6. Answer one of the following questions. Any diagrams included in your answer must be fully annotated. 13 Examiner only Arholwr yn unig Either, (a) Describe (i) the Krebs cycle; (ii) the formation of ATP in the electron transport chain. [Details of glycolysis and the link reaction are not required.] [12] Or (b) Write an account to include the causative organism, symptoms, mode of transmission, treatment and prevention of the disease for (i) cholera; (ii) salmonellosis. [12] (314-01) Turn over.

31 14 Examiner only Arholwr yn unig (314-01)

32 15 Examiner only Arholwr yn unig (314-01) (Total 12 marks)

33 16 Examiner only Arholwr yn unig (314-01)

34 8 Examiner only Arholwr yn unig 4. The molecule shown in the diagram is a nucleotide known in biochemistry as intracellular energy currency. H 2 N O O O P O P O O P O O N N N N O O O OH OH (a) The structure of this molecule consists of a purine base (adenine) and three phosphate groups attached to a pentose (ribose). (i) Name the molecule. [1] \... (ii) Circle the purine base on the diagram. [1] (iii) Name two products that are formed when the molecule in the diagram above has released energy in a cell. [1]... (iv) Why might this energy currency molecule be described as universal? [1] (b) The diagram shows components of a mitochondrion involved in generating the molecule shown in part (a). H + H + H + H + H + H + H + H + H + H + H + Outer Membrane A HH NAD P 1 P 2 P 3 C H + 1 H + C 2 H + Inner Membrane E B (314-01)

35 9 Examiner only Arholwr yn unig (i) Name the areas labelled A and B. [2] A... B... (ii) NAD is used to transport hydrogen atoms. Name two stages of cellular respiration from which NAD may pick up hydrogen atoms. [2] (iii) Hydrogen atoms consist of one proton and one electron. Explain how the components labelled P and C operate to generate an electrochemical gradient. [2] P C (iv) What is the role of the electrons in this system? [1]... (v) Name enzyme E. [1]... (vi) Explain how the enzyme generates ATP. [2] (Total 14 marks) Turn over.

36 3 Examiner only 2. Respiration is carried out as a number of stages. Complete the table by stating the main products of each of the stages in respiration and where, precisely in the cell, each process takes place. [10] Stage of respiration Main products Where it takes place Glycolysis Krebs cycle Electron transport chain [Total 10 marks] (W ) Turn over.

37 2 Examiner only 1. The diagram below shows a molecule of ATP. NH 2 B N HC C N C C N N CH O O O O P O P O P OCH 2 O O O O A H H OH OH C (a) Identify parts A, B and C. [3] A... B... C... (b) To what group of molecules does ATP belong? [1]... (c) Explain why ATP is important in cells. [2] (d) State three sites of ATP synthesis within a cell. [3] (314-01) (Total 9 marks)

38 8 Examiner only 5. The diagram below shows an outline of the stages involved in aerobic respiration. Glycolysis Glucose Triose phosphate NAD Reduced NAD Pyruvate NAD A Reduced NAD B 4-carbon acid 6-carbon acid Reduced electron acceptors C Krebs cycle 5-carbon acid A Oxidised electron acceptors Electron Transport Chain ATP D A (314-01)

39 9 Examiner only (a) Name A, B, C and D. [4] A... B... C... D... (b) (c) Identify all the steps involved in glycolysis by drawing a box around them on the diagram. [1] Precisely where do the Krebs cycle and the electron transport chain occur in a mammalian cell? [2] Krebs cycle... Electron transport chain... (d) (i) Indicate, by writing a letter E on the diagram, where ATP is used in respiration. [1] (ii) Indicate, by writing ATP on the diagram, the two stages, not including the electron transport chain, where ATP is produced during respiration. [1] (e) State the type of enzyme involved in the formation of reduced NAD. [1]... (f) Describe what happens to pyruvate in anaerobic conditions in mammalian cells. [2] (g) Indicate on the diagram, using the correct names, where other respiratory substrates from the breakdown products of lipids enter the aerobic respiration pathway. [2] (Total 14 marks) (314-01) Turn over.

40 4. The diagram outlines the stages involved in respiration. 8 Examiner only 2ATP 6C Sugar Hexose Phosphate Triose Phosphate Triose Phosphate Glycolysis 2H X 2ATP A Pyruvate (3C) CO 2 Cytoplasm Mitochondrion Z 2H (3ATP) X B 4C Compound 6C Compound B X 2H (3ATP) 2H (3ATP) X 4C Compound Krebs cycle 2H (2ATP) CO 2 Y 4C Compound 5C Compound A 1 ATP X 2H (3ATP) CO 2 (a) ATP is produced by phosphorylation during both anaerobic and aerobic respiration. Name the types of phosphorylation which take place at the points labelled A and B. [2] A... phosphorylation (W ) B... phosphorylation

41 9 Examiner only (b) State the type of enzyme responsible for the removal of: (i) carbon dioxide, [1]... (ii) hydrogen. [1]... (c) There are four places where hydrogen acceptors remove hydrogen in the Krebs cycle. (i) Name the hydrogen acceptors at: [2] X... Y... (ii) Explain why these two hydrogen acceptors lead to the production of different numbers of ATP molecules. [1] (d) Complete the table to show the number of ATP molecules formed from one molecule of glucose. [4] Stage Number of ATP molecules formed from reduced hydrogen acceptor Number of ATP molecules formed directly Total number of ATP molecules formed from each Link reaction Krebs cycle (e) (i) Identify the molecule labelled Z. [1]... (ii) State the number of carbon atoms contained in this molecule. [1]... (iii) Describe the formation of molecule Z. [2] (Total 15 marks) (W ) Turn over.

42 6 Examiner only 4. To investigate the relationship between photosynthesis and respiration, unicellular algae were encapsulated in alginate balls. These were then suspended in hydrogen carbonate indicator which can be used to indicate the concentration of dissolved CO 2. A number of small glass tubes were prepared each containing 30 algal balls and the same volume of indicator was added to each. The tubes were each exposed to light of a different intensity. All other conditions were kept constant. After 1 hour a sample of the indicator was taken and placed in a colorimeter. The results are shown in the table below. The colorimeter was set at zero with ph 7.0. In acid conditions the solution turned lighter giving lower (negative) figures and in alkaline conditions the solution turned darker giving higher (positive) figures. Light intensity (arbitrary units) Colorimeter reading (arbitrary units) (a) Plot a graph on the paper opposite. [4] (b) Describe the results from the graph. [2] (c) What name is given to the point where your line crosses the X axis? [1]... (d) What precisely is happening at this point? [1] (e) Explain the results using your knowledge of photosynthesis and respiration. [4] (314-01) (Total 12 marks)

43 7 Examiner only (314-01) Turn over.

44 9 Examiner only (d) Describe and explain the shape of the curve when the bacteria are grown in lactose and glucose together. [4] (Total 11 marks) 6. Complete the table below comparing ATP synthesis in mitochondria and chloroplasts. Oxidative phosphorylation Cyclic photophosphorylation Non cyclic photophosphorylation Requires light Requires oxygen Produces oxygen Number of proton pumps involved Source of electrons Final electron acceptor (Total 6 marks) (314-01) Turn over.

45 12 Examiner only 8. Answer one of the following questions. Any diagrams included in your answer must be fully annotated. Either, (a) Describe the process of glycolysis (diagrams alone will not be sufficient). State the products of glycolysis and explain what happens to each product in animal and yeast cells under anaerobic conditions. [10] Or (b) Explain what is meant by an antibiotic. What processes have led to antibiotic resistance and describe how this resistance has arisen. [10] (314-01)

46 13 Examiner only (314-01) Turn over.

47 14 Examiner only (314-01) (Total 10 marks)

1 Respiration is a vital process in living organisms. All organisms carry out glycolysis. The Krebs cycle also occurs in some organisms.

1 Respiration is a vital process in living organisms. All organisms carry out glycolysis. The Krebs cycle also occurs in some organisms. (a) The diagram below shows some of the stages in glycolysis, using