Chapter 7 – Energy Metabolism
MULTIPLE CHOICE
1. Which process describes the sum of all chemical reactions that go on in living cells?
a.
Digestion
b.
Metabolism
c.
Absorption
d.
Catabolism
e.
Anabolism
2. In photosynthesis, the plant uses energy from the sun, plus water and carbon dioxide, to synthesize
____.
a.
carbohydrates only
b.
fats and carbohydrates only
c.
protein and carbohydrates only
d.
fats, proteins, and carbohydrates
e.
protein only
3. A typical cell contains “powerhouses,” which is another name for ____.
a.
DNA
b.
ribosomes
c.
mitochondria
d.
electron transport chains
e.
RNA
4. A feature of catabolic reactions is that they ____.
a.
involve the release of energy
b.
occur only in mitochondria
c.
involve consumption of energy
d.
occur only during loss of body weight
e.
require carbon dioxide
5. What term is specific to reactions in which simple compounds are combined into more complex
molecules?
a.
Anabolic
b.
Catabolic
c.
Ergogenic
d.
Gluconeogenic
e.
Anaerobic
6. The site of lipid synthesis in the cell is the ____.
a.
nucleus
b.
Golgi bodies
c.
mitochondria
d.
smooth endoplasmic reticulum
e.
exoplasm
7. Which reaction is characterized as anabolic?
a.
Pyruvate synthesis from glucose
b.
Acetyl CoA synthesis from cholesterol
c.
Carbon dioxide synthesis from citric acid
d.
Cholesterol synthesis from acetyl CoA molecules
e.
Hydrolysis of glycogen to glucose
8. Which reaction is characterized as catabolic?
a.
Glucose formation from glycerol
b.
Pyruvate formation from glucose
c.
Albumin formation from amino acids
d.
Palmitic acid formation from acetate
e.
Formation of triglycerides from glycerol and fatty acids
9. What is the approximate percent efficiency of conversion of food energy to ATP energy in the body?
a.
30%
b.
50%
c.
70%
d.
90%
e.
99%
10. In the adult body, food energy not stored as fat or glycogen is lost as ____.
a.
heat
b.
photons
c.
carbon dioxide
d.
electromagnetic radiation
e.
methane
11. Which statement defines a coenzyme?
a.
A unit consisting of an enzyme bound to reactants plus ATP
b.
An organic molecule required for the functioning of an enzyme
c.
The small, active part of an enzyme that binds to the organic reactants
d.
An inactive enzyme that becomes functional upon contact with specific cofactors
e.
An enzyme precursor
12. Which metabolic reaction occurs when a cell uses energy?
a.
ATP gains a phosphate group and becomes ADP.
b.
ADP gains a phosphate group and becomes ATP.
c.
ATP releases a phosphate group and becomes ADP.
d.
ADP releases a phosphate group and becomes ATP.
e.
ADP and ATP cycle back and forth repeatedly.
13. What is the major energy carrier molecule in most cells?
a.
ATP
b.
Glucose
c.
Pyruvate
d.
A kcalorie
e.
Acetyl CoA
14. Which statement describes a correct energy-yielding endpoint?
a.
Carbohydrates yield glucose only when proteins are not available.
b.
Proteins cannot yield fat stores.
c.
Fatty acids yield amino acids.
d.
Glycerol yields nonessential amino acids when nitrogen is present.
e.
Fatty acids yield glucose.
15. Glycolysis is the conversion of ____.
a.
glycogen to fat
b.
glycogen to protein
c.
glucose to pyruvate
d.
glucose to glycogen
e.
glycogen to glucose
16. The series of reactions involving the conversion of glucose to pyruvate is known as ____.
a.
pyrolysis
b.
glycolysis
c.
beta-oxidation
d.
coupled reaction
e.
gluconeogenesis
17. Which of the following is a feature of aerobic metabolism?
a.
Little or no oxygen is consumed.
b.
Lactic acid is a major byproduct.
c.
Energy is produced more slowly than in anaerobic metabolism.
d.
Pyruvate is converted to glucose by reverse glycolysis to yield a net of 2 ATPs.
e.
The process can only be sustained for relatively brief periods of time.
18. Which statement describes lactate production by muscle cells?
a.
It occurs only during intense exercise.
b.
When rapid, it causes muscle fatigue.
c.
It produces lactate that may eventually be used by the liver for glucose production.
d.
It lowers the pH of the muscle cell, thereby lowering muscle performance.
e.
It is an aerobic process.
19. An aerobic reaction is one that requires ____.
a.
alcohol
b.
oxygen
c.
nitrogen
d.
ammonia
e.
glucose
20. The Cori cycle involves the interconversion of ____.
a.
lactate and glucose
b.
glucose and amino acids
c.
pyruvate and citric acids
d.
fatty acids and acetyl CoA
e.
glycerol and glucose
21. 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 ____.
a.
lactate
b.
glucose
c.
citric acid
d.
fatty acids
e.
galactate
22. What is a possible metabolic reaction in the cell?
a.
Pyruvate to urea
b.
Lactate to pyruvate
c.
Acetyl CoA to pyruvate
d.
Carbon dioxide to glycerol
e.
Fatty acids to glucose
23. Which nutrient can be made from compounds composed of 2-carbon skeletons?
a.
Glucose
b.
Fructose
c.
Glycogen
d.
Fatty acids
e.
Pyruvate
24. What is a possible fate of acetyl CoA?
a.
Degradation to urea
b.
Synthesis to glycerol
c.
Synthesis to fatty acids
d.
Degradation to ammonia
e.
Storage in lipids
25. Fatty acid oxidation results in the direct production of ____.
a.
ketones
b.
fructose
c.
pyruvate
d.
acetyl CoA
e.
lactate
26. Production of excessive amounts of acetyl CoA molecules leads to the synthesis of ____.
a.
fatty acids only
b.
fatty acids and glucose only
c.
fatty acids and fructose only
d.
fatty acids, glucose, and amino acids
e.
amino acids only
27. What percentage (by weight) of a triglyceride molecule can be converted to glucose?
a.
0%
b.
5%
c.
25%
d.
50%
e.
75%
28. How many acetyl CoA molecules may be obtained from oxidation of a 16-carbon fatty acid?
a.
2
b.
4
c.
6
d.
8
e.
16
29. An immediate consequence of a cellular deficiency of oxaloacetate is a slowing of ____.
a.
glycolysis
b.
the TCA cycle
c.
lactate synthesis
d.
ketone formation
e.
protein excretion
30. Where do the TCA cycle reactions take place?
a.
Golgi bodies
b.
Endoplasmic reticulum
c.
Nucleus of the mitochondria
d.
Inner compartment of the mitochondria
e.
Outer membrane of the Golgi bodies
31. After digestion and absorption, an amino acid not used to build protein will first be subjected to ____.
a.
removal of its amino group
b.
removal of its carboxyl group
c.
hydrolysis of its peptide bond
d.
condensation of its peptide bond
e.
removal of its acetyl group
32. Which process leads to the production of urea?
a.
Oxidation of glucose
b.
Oxidation of amino acids
c.
Incomplete oxidation of fatty acids
d.
Synthesis of protein from amino acids
e.
Incomplete oxidation of glycerol
33. When energy-yielding nutrients are consumed in excess, which one(s) can lead to storage of fat?
a.
Fat only
b.
Carbohydrate only
c.
Fat and carbohydrate only
d.
Fat, carbohydrate, and protein
e.
Protein and fat only
34. If the carbohydrate content of the diet is insufficient to meet the body’s needs for glucose, what can be
converted to glucose?
a.
Fatty acids
b.
Acetyl CoA
c.
Amino acids
d.
Carbon dioxide
e.
Urea
35. When protein consumption is in excess of body needs and energy needs are met, the excess amino
acids are metabolized and the energy in the molecules is ____.
a.
stored as fat only
b.
excreted in the feces
c.
stored as amino acids only
d.
stored as glycogen and fat
e.
excreted in the urine
36. What are the products of the complete oxidation of fatty acids?
a.
Urea and acetone
b.
Fatty acids and glycerol
c.
Carbon, hydrogen, and oxygen
d.
Water, carbon dioxide, and energy
e.
Pyruvate and acetyl CoA
37. In addition to energy, what are the principal end products of cellular oxidation of carbohydrates?
a.
Water and carbon dioxide
b.
Carbon, hydrogen, and urea
c.
Indigestible fiber and nitrogen
d.
Monosaccharides and amino acids
e.
Oxygen and carbolic acid
38. Which of the following is a feature of the electron transport chain?
a.
It captures energy in the high-energy bonds of ATP.
b.
It pumps carbon dioxide across the mitochondrial membrane.
c.
It is composed of a series of coenzymes that transfer electrons up a concentration gradient.
d.
It combines oxygen from carbon dioxide with hydrogen generated from the splitting of
water.
e.
It facilitates the transport of sodium and calcium.
39. What accounts for the higher energy density of a fatty acid compared with the other energy-yielding
nutrients?
a.
Fatty acids have a lower percentage of hydrogen-oxygen bonds.
b.
Fatty acids have a greater percentage of hydrogen-carbon bonds.
c.
Other energy-yielding nutrients have a lower percentage of oxygen-carbon bonds.
d.
Other energy-yielding nutrients undergo fewer metabolic reactions, thereby lowering the
energy yield.
e.
Other energy-yielding nutrients have a lower percentage of oxygen-hydrogen bonds.
40. 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 ____.
a.
carbon
b.
oxygen
c.
nitrogen
d.
hydrogen
e.
potassium
41. Which of the following can be synthesized from all three energy-yielding nutrients?
a.
Lactate
b.
Glycogen
c.
Acetyl CoA
d.
Oxaloacetate
e.
Glucose
42. What is the most likely explanation for the body’s higher metabolic efficiency of converting a
molecule of corn oil into stored fat compared with a molecule of sucrose?
a.
The enzymes specific for metabolizing absorbed fat have been found to have higher
activities than those metabolizing sucrose.
b.
The absorbed corn oil is transported to fat cells at a faster rate than the absorbed sucrose,
thereby favoring the uptake of corn oil fat.
c.
There are fewer metabolic reactions for disassembling the corn oil and re-assembling the
parts into a triglyceride for uptake by the fat cells.
d.
Because corn oil has a greater energy content than sucrose, conversion of these nutrients
into stored fat requires a smaller percentage of the energy from the corn oil.
e.
The metabolic reactions for disassembling the corn oil and re-assembling the parts into a
triglyceride for uptake by the fat cells require less energy themselves.
43. Storing excess energy from dietary carbohydrate as body fat requires ____ percent of the ingested
energy intake.
a.
5
b.
15
c.
25
d.
35
e.
45
44. If a person consumes 100 kcalories in excess of energy needs from olive oil, approximately what
percentage of the kcalories are stored in the body?
a.
55%
b.
65%
c.
75%
d.
85%
e.
95%
45. Which of the following is a characteristic of the metabolism of specific macronutrients?
a.
The rate of fat oxidation does not change when fat is eaten in excess.
b.
The rate of protein oxidation does not change when protein is eaten in excess.
c.
The rate of glucose oxidation does not change when carbohydrate is eaten in excess.
d.
The conversion of dietary glucose to fat is the major pathway of carbohydrate utilization.
e.
The conversion of protein to muscle is hastened when protein intake exceeds protein
requirements.
46. How does excess carbohydrate intake contribute to obesity?
a.
It is efficiently converted to storage fat.
b.
It spares oxidation of body fat and dietary fat.
c.
It stimulates glucagon release, resulting in inhibition of fatty acid oxidation.
d.
It stimulates pancreatic lipase secretion, which results in higher dietary fat absorption.
e.
It results in large amounts of glycogen storage that is increased as carbohydrate
consumption increases.
47. What is a feature of the metabolism of surplus dietary fat?
a.
Excess fat is almost all stored.
b.
Excess fat promotes increased fat oxidation.
c.
Excess fat spares breakdown of body proteins.
d.
Conversion of excess fat to storage fat is inefficient.
e.
Excess dietary fat facilitates conversion of other macronutrients to fat.
48. Of the total amount of glucose energy consumed by the body, approximately what percentage is used
by the brain and nerve cells?
a.
10%
b.
30%
c.
50%
d.
70%
e.
90%
49. During the first few days of a fast, what energy source provides about 90% of the glucose needed to
fuel the body?
a.
Protein
b.
Ketones
c.
Glycogen
d.
Triglycerides
e.
Glycerol
50. Which dietary nutrient would most rapidly reverse a state of ketosis in a starving person?
a.
Nonessential fatty acids
b.
Protein
c.
Amino acids
d.
Carbohydrate
e.
Essential fatty acids
51. How soon would death occur from starvation if the body was unable to shift to a state of ketosis?
a.
3 to 5 days
b.
7 to 10 days
c.
within 3 weeks
d.
4 to 6 weeks
e.
6 to 12 weeks
52. Which item is used to supply some of the fuel needed by the brain only after the body has been fasting
for a while?
a.
Ketones
b.
Glycerol
c.
Fatty acids
d.
Amino acids
e.
Protein
53. Which of the following is classified as a ketone body?
a.
Sorbitol
b.
Pyruvate
c.
Acetyl CoA
d.
Acetoacetate
e.
Oxaloacetate
54. What organ is the major site for gluconeogenesis?
a.
Liver
b.
Brain
c.
Muscle
d.
Small intestine
e.
Pancreas
55. Nationally, what percentage of college students are frequent binge drinkers?
a.
5%
b.
10%
c.
20%
d.
30%
e.
50%
56. What percentage of U.S. adult men are classified as drinking excessively? What percentage of women
are doing the same?
a.
2%; 5%
b.
5%; 2%
c.
8%; 3%
d.
10%; 4%
e.
11%; 8%
57. The amount of ethanol in a typical “drink” is ____.
a.
0.5 ounce
b.
1 ounce
c.
1.5 ounces
d.
2 ounces
e.
4 ounces
58. Approximately how many kcal are contained in 3 ounces of 80-proof rum?
a.
50 kcal
b.
100 kcal
c.
150 kcal
d.
200 kcal
e.
400 kcal
59. What is one explanation for the generally lower tolerance for alcohol in women in comparison to men?
a.
Women fast more often.
b.
Women do not eat as much food with the alcohol.
c.
Women consume more of their alcohol in sweetened drinks.
d.
Women have lower amounts of stomach alcohol dehydrogenase.
e.
Women are more likely to gulp their drinks.
60. What is the primary organ that oxidizes alcohol?
a.
Brain
b.
Liver
c.
Pancreas
d.
Stomach
e.
Small intestine
61. What would be the best method of slowing alcohol absorption?
a.
Not eating
b.
Eating protein snacks
c.
Drinking caffeinated drinks
d.
Eating carbohydrate snacks
e.
Fasting 6 to 8 hours before drinking
62. The metabolism of alcohol begins in the ____.
a.
liver
b.
brain
c.
stomach
d.
intestines
e.
mouth
63. What is acetaldehyde?
a.
An intermediate in fatty acid synthesis
b.
An intermediate in alcohol metabolism
c.
The first product of fatty acid catabolism
d.
The TCA compound that combines with acetyl CoA
e.
The final product of alcohol metabolism.
64. In the average healthy person, about how much time is required by the liver to process the alcohol in a
typical drink?
a.
15 minutes
b.
30 minutes
c.
1 hour
d.
2 hours
e.
4 hours
65. Excess alcohol intake leads to a reduction in the synthesis rate of ____.
a.
liver fat
b.
liver glucose
c.
ketone bodies