York University - KINE 4020

Chapter 7 Metabolism: Transformations and Interactions

MULTIPLE CHOICE

1)Which of the following reactions describes the sum of all chemical reactions that go on in living cells?

1. 1. digestion
   2. metabolism
   3. absorption
   4. catabolism

2. In photosynthesis, the plant uses energy from the sun, plus water and carbon dioxide, to synthesize which of the following molecules?
   1. carbohydrates only
   2. fats and carbohydrates only
   3. protein and carbohydrates only
   4. fats, proteins, and carbohydrates

3. A typical cell contains “powerhouses,” which is another name for which of the following structures?
   1. DNA
   2. ribosomes
   3. mitochondria
   4. rough endoplasmic reticulum

4. Which of these terms is specific to reactions in which simple compounds are combined into more com- plex molecules?
   1. anabolic
   2. catabolic
   3. ergogenic
   4. gluconeogenic

5. The site of lipid synthesis in the cell is which of these bodies?
   1. nucleus
   2. Golgi bodies
   3. mitochondria
   4. smooth endoplasmic reticulum

6. Which of the following reactions is an example of an anabolic reaction?
   1. pyruvate synthesis from glucose
   2. acetyl-coA synthesis from cholesterol
   3. carbon dioxide synthesis from citric acid
   4. cholesterol synthesis from acetyl-coA molecules

7. The formation of glycogen by the liver cell is an example of which of these reactions?
   1. oxidation
   2. glycolysis
   3. anabolism
   4. catabolism

8. Which of the following processes is an example of a catabolic reaction?
   1. glucose formation from glycerol
   2. urea formation from an amino acid
   3. albumin formation from amino acids
   4. palmitic acid formation from acetate

9. Which of the following best characterizes catabolic reactions?
   1. involve release of energy
   2. occur only in mitochondria
   3. involve consumption of energy
   4. occur only when dietary energy is inadequate

10. Which of the following is among the functions of the liver?
    1. excretion of urea
    2. synthesis of the final active form of vitamin D
    3. production of red blood cells
    4. conversion of fructose to glucose

11. What is the approximate percent efficiency of conversion of food energy to ATP energy in the body?
    1. 20 percent
    2. 50 percent
    3. 80 percent
    4. 99 percent

12. In the adult body, most of the food energy NOT stored as fat or glycogen is lost as which of the follow- ing forms of energy?
    1. heat
    2. photons
    3. macronutrients in stool
    4. electromagnetic radiation

13. Which of the following defines a coenzyme?
    1. a unit consisting of an enzyme bound to reactants plus ATP
    2. an organic molecule required for the functioning of an enzyme
    3. the small, active part of an enzyme that binds to the organic reactants
    4. an inactive enzyme that becomes functional upon contact with specific cofactors

14. The hydrolysis of ATP that often occurs simultaneously with the synthesis of many compounds is an example of which of the following processes?
    1. coupled reactions
    2. tandem cleavages
    3. metabolic couplings
    4. high energy processes

15. Which of the following metabolic reactions occurs when a cell uses energy?
    1. ATP gains a phosphate group and becomes ADP.
    2. ADP gains a phosphate group and becomes ATP.
    3. ATP releases a phosphate group and becomes ADP.
    4. ADP releases a phosphate group and becomes ATP.

16. Which is the major energy carrier molecule in most cells?
    1. ATP
    2. glucose
    3. pyruvate
    4. water

17. The basic units derived from food that enter the TCA cycle directly or through pyruvate and acetyl CoA include all of the members of which of the following groups?
    1. glycerol, starches, glucose
    2. starches, peptides, fatty acids
    3. fatty acids, glycerol, amino acids
    4. amino acids, peptides, glucose

18. Approximately what percentage of the body’s energy expenditure is furnished by amino acids?
    1. 1–5 percent
    2. 10–15 percent
    3. 25–35 percent
    4. 50–65 percent

19. Which of the following CANNOT be formed from acetyl-coA molecules?
    1. glucose
    2. cholesterol
    3. stearic acid
    4. carbon dioxide

20. Which of the following conversions is termed glycolysis?
    1. glycogen to fat
    2. glycogen to protein
    3. glucose to pyruvate
    4. glucose to glycogen

21. The series of reactions involving the conversion of glucose to pyruvate is known as which of the fol- lowing?
    1. pyrolysis
    2. glycolysis
    3. beta-oxidation
    4. coupled reaction

22. Which of the following is an aspect of glycolysis?
    1. It is irreversible.
    2. It can occur only in the presence of oxygen.
    3. It can occur only in the absence of oxygen.
    4. It generates 2 molecules of pyruvate for each molecule of glucose.

23. Which of the following distinguishes aerobic metabolism from anaerobic metabolism?
    1. Little or no oxygen is consumed.
    2. Lactic acid is a major byproduct.
    3. Energy is produced more slowly.
    4. It yields energy for only short periods.

24. Which of the following series outlines the overall sequence of events in the complete oxidation of glucose?
    1. Cori cycle, TCA cycle, glycolysis
    2. glycolysis, TCA cycle, electron transport chain
    3. electron transport chain, TCA cycle, Cori cycle
    4. TCA cycle, electron transport chain, glycolysis

25. An aerobic reaction is one that requires which of the following components?
    1. alcohol
    2. oxygen
    3. nitrogen
    4. ammonia

26. The Cori cycle involves the interconversion of which of the following pairs?
    1. lactate and glucose
    2. glucose and amino acids
    3. pyruvate and citric acids
    4. fatty acids and acetyl-coA

27. Your roommate Demetrius is participating in a weightlifting course and complains of a burning pain during workouts. You explain to Demetrius that this is due to his muscles converting excess pyruvate to which of the following compounds?
    1. lactate
    2. glycerol
    3. acetyl-coA
    4. amino acids

28. When a person is performing intense physical exercise and begins to feel fatigue and a burning pain in the muscles, the response of the muscles is to synthesize more of which of the following compounds?
    1. lactate
    2. glucose
    3. citric acid
    4. fatty acids

29. Which of the following pathways from pyruvate is irreversible?
    1. to glucose
    2. to glucogenic amino acids
    3. lactate
    4. acetyl CoA

30. Which of the following groups contains only compounds that can be formed from metabolized gluc- ose?
    1. acetyl CoA, muscle glycogen, urea
    2. acetyl-CoA, muscle glycogen, amino acids
    3. acetyl CoA, amino acids, ammonia

1. 4. acetyl CoA, muscle glycogen, ammonia

31. Which of the following nutrients can be made from compounds composed of 2-carbon skeletons?
    1. glucose
    2. fructose
    3. glycogen
    4. fatty acids

32. Which of the following is a possible fate of acetyl-coA?
    1. degradation to urea
    2. synthesis to glycerol
    3. synthesis to fatty acids
    4. degradation to ammonia

33. What is the first product of fatty acid catabolism?
    1. glycerol
    2. pyruvate
    3. acetyl-coA
    4. triglycerides

34. Fatty acid oxidation results in the direct production of which of these compounds?
    1. ketones
    2. fructose
    3. pyruvate
    4. acetyl-coA

35. Production of excessive amounts of acetyl-coA molecules leads to the synthesis of which of the fol- lowing compounds?
    1. fatty acids only
    2. fatty acids and glucose only
    3. fatty acids and fructose only
    4. fatty acids, glucose, and amino acids

36. In a triglyceride that contains 54 carbon atoms, how many can become part of glucose?
    1. 3
    2. 9
    3. 54

d. 108

37. Approximately what percentage of the weight of triglycerides can be converted to glucose?
    1. 5 percent
    2. 10 percent
    3. 20 percent
    4. 30 percent

38. What percentage (by weight) of a triglyceride molecule can be converted to glucose?
    1. 0 percent
    2. 5 percent
    3. 50 percent
    4. 100 percent

39. How many acetyl-coA molecules may be obtained from oxidation of an 18-carbon fatty acid?
    1. 3
    2. 6
    3. 9
    4. 18

40. In which of the following groups can all of the dietary components be used to synthesize and store gly- cogen?
    1. lactose, animal fats, wheat starch
    2. animal fats, wheat starch, plant proteins
    3. wheat starch, plant proteins, lactose
    4. plant proteins, lactose, vegetable oils

41. Which of the following compounds can be formed from fatty acids?
    1. ketones
    2. glucose
    3. amino acids
    4. urea

42. In which of the following groups can all of the dietary components be used to make body proteins?
    1. glucose, glycerol, fatty acids
    2. glycerol, fatty acids, amino acids
    3. fatty acids, amino acids, glucose
    4. amino acids, glucose, glycerol

43. Which of these is the immediate fate of excess dietary protein in the body?
    1. storage
    2. reduction
    3. oxidation
    4. deamination

44. Which of the following processes leads to the production of urea?
    1. oxidation of glucose
    2. oxidation of amino acids
    3. incomplete oxidation of fatty acids
    4. synthesis of protein from amino acids

45. After digestion and absorption, an amino acid NOT used to build protein will first be subjected to which of the following processes?
    1. removal of its amino group
    2. removal of its carboxyl group
    3. hydrolysis of its peptide bond
    4. condensation of its peptide bond

46. When protein consumption is in excess of body needs and energy needs are met, what is the fate of the energy in the excess amino acid molecules?
    1. stored as fat only
    2. stored as glycogen only
    3. stored as amino acids only
    4. stored as glycogen and fat

47. When energy-yielding nutrients are consumed in excess, which one(s) can lead to storage of fat?
    1. fat only
    2. carbohydrate only
    3. fat and carbohydrate only
    4. fat, carbohydrate, and protein

48. If the carbohydrate content of the diet is insufficient to meet the body’s needs for glucose, which of the following compounds can be converted to glucose?
    1. fatty acids
    2. acetyl-coA
    3. amino acids

1. 4. carbon dioxide

49. An immediate consequence of a cellular deficiency of oxaloacetate is a slowing of which of these reac- tions?
    1. glycolysis
    2. the TCA cycle
    3. lactate synthesis
    4. ketone formation

50. In which of the following groups can all of the compounds serve as a precursor for oxaloacetate syn- thesis?
    1. fat, starch, glucose
    2. starch, glucose, protein
    3. glucose, protein, fat
    4. protein, fat, starch

51. What are the products from the complete oxidation of fatty acids?
    1. urea and acetone
    2. gatty acids and glycerol
    3. carbon, hydrogen, and oxygen
    4. water, carbon dioxide, and energy

52. In addition to energy, which of these components are the principal end products of cellular oxidation of carbohydrates?
    1. water and carbon dioxide
    2. carbon, hydrogen, and urea
    3. indigestible fibre and nitrogen
    4. monosaccharides and amino acids

53. In which of the following groups are the products all generated via the TCA cycle or electron transport chain?
    1. water, energy, ammonia
    2. energy, ammonia, carbon dioxide
    3. ammonia, carbon dioxide, water
    4. carbon dioxide, water, energy

54. At what point is oxygen used in the electron transport chain?
    1. at the end

1. 2. at every step
   3. at the beginning
   4. when ATP is synthesized

55. In which of the following groups are the products all generated from the electron transport chain path- way?
    1. CO2, urea, water
    2. urea, water, energy
    3. water, energy, CO₂
    4. energy, CO2, urea

56. Which of the following accounts for the higher energy density of a fatty acid compared with the other energy-yielding nutrients?
    1. Fatty acids have a lower percentage of hydrogen-carbon bonds.
    2. Fatty acids have a greater percentage of hydrogen-carbon bonds.
    3. Other energy-yielding nutrients have a lower percentage of oxygen-carbon bonds.
    4. Other energy-yielding nutrients undergo fewer metabolic reactions, thereby lowering the energy yield.

57. The number of ATP molecules that can be produced from a molecule of protein, fat, or carbohydrate is generally related to the number of atoms of which element?
    1. carbon
    2. oxygen
    3. nitrogen
    4. hydrogen

58. Approximately how many molecules of ATP are generated from the complete oxidation of 1 molecule of glucose?
    1. 4
    2. 9
    3. 32

d. 130

59. Approximately how many ATP molecules are synthesized from the complete oxidation of 1 molecule of palmitic acid?
    1. 9
    2. 27
    3. 98

d. 129