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Biochemistry
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Natalie Pemberton-Parris – 00027917 2nd October 2014
CHEM 121 Carbohydrate Metabolism Worksheet
SECTION A: (21 marks)
1. Write an equation which represents energy being used. (1 mark)Ans: ATP -- ADP + P i
2. Write an equation which represents energy being produced. (1 mark)Ans: ADP + Pi -- ATP
3. When glucose undergoes the series of reactions known as glycolysis, what molecule is it converted into? (1 mark)Ans: Two 3-carbon molecules of Pyruvate.
4. What are the 2 respiration pathways a cell can use and what determines which pathway is used? (3 marks)Ans: Aerobic and Anaerobic respiration; the presences or absence of oxygen.
5. Write the overall equation for aerobic cellular respiration. (1 mark)Ans: C6H12O6 + 6O2 ---> 6CO2 + 6H2O + 36 ATP
6. What are the 3 stages of the aerobic cellular respiration process? (3 marks) Ans: Glycolysis, Krebs cycle, and ETC
7. What stage of cellular respiration is common to both aerobic and anaerobic cellular respiration? (1 marks)Ans: Glycolysis
8. Where in the cell does glycolysis occur? (1 marks)Ans: Cytoplasm
9. In what part of which organelle does the Krebs (Citric Acid) cycle occur? (2 marks)Ans: Matrix of the Mitochondria
10. In what part of which organelle does the electron transport chain occur? (2 marks)Ans: In the inner membrane of the mitochondria
11. What is the overall production of ATP molecules made in glycolysis per glucose molecule metabolized? (1 marks)Ans: 2 ATP
12. In which two stages of cellular respiration is carbon dioxide made? (2 marks)Ans: Krebs cycle & where pyruvate is converted to acetyl Coa
13. In which stage of cellular respiration is water made? (1 mark)Ans: Electron transport chain; oxidative phosphorylation
14. In which stage of respiration are the high energy electron carriers (NADH and FADH2) produced? (1 mark) Ans: Krebs cycle
SECTION B (25 marks)
15. If sufficient oxygen is not available within a muscle cell, what is the pyruvate there converted into? (1 mark)Ans: Lactic Acid
16. If sufficient oxygen is available within a muscle cell, what is the pyruvate there converted into? (1 mark)Ans: Acetyl CoA
17. Pyruvate present in certain bacteria is converted into what molecule? (2 marks) Ans: Ethanol and Carbon Dioxide
18. Name the molecule which needs to be regenerated during lactic fermentation in order for glycolysis to continue. (1 mark)Ans: NAD+
19. What are the products of lactate fermentation? (1 mark)Ans: Lactic acid and NAD+
20. What are the products of ethanol fermentation? (2 marks)Ans: Ethanol, Alcohol and Carbon Dioxide
21. Name the enzyme which creates the -1, 4-glycosidic linkages during glycogenesis. (1 mark)Ans: Glycogen synthase
22. Name the enzyme which creates the -1, 6-glycosidic linkages during glycogenesis. (1 mark)Ans: Branching enzyme
23. Name two important molecules which are necessary for glycogenesis to take place. (2 marks)Ans: Glucose and ATP; UDP and UTP
24. State the function of the enzyme glycogen phosphorylase during glycogenolysis. (1 mark)Ans: Glycogen phosphorylase breaks the -1, 4-glycosidic linkages until there are 4 glucose residues remain by the 1, 6 branch
25. State the function of the enzyme glucan transferase during glycogenolysis. (1 mark)Ans: Glucan transferase breaks the last 1, 4 linkage then transfers the last group of 3 to another straight chain forming another 1, 4 linkage .
26. State the function of the de-branching enzyme during glycogenolysis. (1 mark)Ans: The de-branching enzyme breaks the last alpha 1, 6 Glycosidic linkage to release the last glucose.
27. Gluconeogenesis is almost a reversal of which aspect of carbohydrate metabolism? (1 mark)Ans: Glycolysis but there are three irreversible steps.
28. What molecule is present during gluconeogenesis but not during the aspect of carbohydrate metabolism mentioned in question 27. (1 mark)Ans: Oxaloacetate
29. The hormone insulin activates which reaction pathways of carbohydrate metabolism? (2 marks)Ans: Glycogenesis and Glycolysis
30. The hormone glucagon activates which reaction pathways of carbohydrate metabolism? (2 marks)
Ans: Glycogenolysis and Gluconeogenesis
31. Are insulin levels low in type 1 diabetes mellitus? (1 mark)Ans: Yes
32. Explain your answer for question 31. (1 mark)Ans: Type 1 or juvenile onset diabetes generally referred as insulin dependent diabetes. Type I diabetes is characterized by an absolute deficiency of insulin caused by beta-cell destruction of the Islets of Langerhans in the pancreas. It is clinically characterized by hyperglycemia (high blood glucose) and a propensity towards diabetic ketoacidosis.
33. Are insulin levels low in type 2 diabetes mellitus? (1 mark)Ans: No
34. Explain your answer for question 33. (1 mark)Ans: Diabetes is a problem with your body that causes blood glucose (sugar) levels to rise higher than normal. This is also called hyperglycemia. Type 2 diabetes is the most common form of diabetes. With type 2 diabetes your body does not use insulin properly. This is called insulin resistance which is the decreased ability of target tissues (liver, adipose and insulin) to respond properly to normal circulating concentrations of insulin. It is commonly associated with obesity. There is also genetic predisposition and diabetic ketoacidosis is much less than type 1.