General, Organic & Biological Chemistry, 5e (Timberlake)
Chapter 22 Metabolic Pathways for Carbohydrates
22.1 Multiple-Choice Questions
1) Which of the following is true for prokaryotic cells?
A) They are more complex than eukaryotic cells.
B) They are larger than eukaryotic cells.
C) They contain mitochondria.
D) They are found in animals.
E) They do not contain a nucleus.
2) A compound that is formed in a metabolic oxidation is called a(n)
A) product.
B) enzyme.
C) metabolite.
D) food.
E) cofactor.
3) Which of the following does not require energy from ATP hydrolysis?
A) digestion
B) muscle contraction
C) transport across cell membranes
D) sending nerve signals
E) synthesis of an enzyme
4) The process by which complex molecules are broken down into simpler ones for the body’s use is
called
A) metabolism.
B) catabolism.
C) anabolism.
D) glucogenesis.
E) gluconeogenesis.
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5) The process of building up new molecules in the cell is called
A) metabolism.
B) catabolism.
C) anabolism.
D) glycolysis.
E) transamination.
6) Overall, catabolic reactions
A) release energy.
B) take in energy.
C) occur mainly in the liver.
D) occur outside the cell membrane.
E) take place in the nucleus of the cell.
7) Anabolic reactions are reactions that
A) use oxidation but not reduction.
B) break down large molecules into smaller ones.
C) take place in the mitochondria.
D) use energy.
E) give off energy.
8) How many main stages of catabolism are there?
A) one
B) two
C) three
D) four
E) five
9) The first stage of catabolism is
A) the citric acid cycle.
B) production of pyruvate.
C) production of acetyl CoA.
D) buildup of macromolecules from monomers.
E) digestion of large molecules.
10) The middle stage of catabolism is the point at which
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A) acetyl CoA is produced.
B) monomers are produced from macromolecules.
C) macromolecules are made from monomers.
D) glycogen is converted to glucose.
E) excess nutrients are stored as fats.
11) Protein synthesis takes place
A) in the mitochondria.
B) on the endoplasmic reticulum.
C) in the nucleus.
D) on the ribosomes.
E) in the cytosol.
12) The synthesis of glycogen can be classified as a(n)
A) catabolic reaction.
B) anabolic reaction.
C) digestion reaction.
D) phosphorylation reaction.
E) β-oxidation reaction.
13) The final products of catabolic reactions are
A) carbon dioxide, water, and ammonia.
B) glucose, lipids, and glycogen.
C) lipids, oxygen, and water.
D) RNA and DNA.
E) lipids and carbohydrates.
14) The main compound used to release energy for metabolism is
A) sucrose.
B) glucose phosphate.
C) adenosine triphosphate.
D) ribonucleic acid.
E) NAD+.
15) The components of ATP are
4
A) adenosine, ribose, and triphosphate.
B) aniline and triphosphate.
C) alanine, ribose, and triphosphate.
D) adenine, ribose, and triphosphate.
E) adenosine, deoxyribose, and triphosphate.
16) The hydrolysis of ATP to ADP is
A) endothermic.
B) exothermic.
C) isothermic.
D) an oxidation.
E) a reduction.
17) The energy from the hydrolysis of ATP to ADP is
A) 31 kcal/mole.
B) 7.3 kcal/mole.
C) 73 kcal/mole.
D) 10. kcal/mole.
E) 4.0 kcal/mole.
18) The symbol Pi stands for
A) inorganic phosphate.
B) inert pyrophosphate.
C) insoluble phosphate.
D) isomers of phosphate.
E) irreversible phosphorylation.
19) The hydrolysis of ADP to give AMP and Pi, releases approximately the same amount of energy as
A) sucrose breakdown.
B) protein digestion.
C) glucose oxidation.
D) glycogen production.
E) ATP → ADP + Pi.
20) Muscle contraction requires
A) copper ion and ATP.
B) iron.
C) calcium ion and ATP.
D) lipid hydrolysis.
E) carbon dioxide.
21) Muscle contraction is an example of a(n)
A) anabolic process.
B) catabolic process.
C) glucose storage process.
D) protein degradation process.
E) lipid hydrolysis process.
22) Which coenzyme is the electron acceptor in the following reaction?
H H
| |
– C – C – → – C = C –
| | | |
A) FAD
B) NAD+
C) FMN
D) NADH
E) FADH2
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23) Which coenzyme is the electron acceptor in the following reaction?
OH O
|
– C – → – C –
|
H
A) FAD
B) NAD+
C) FMN
D) NADH
E) FADH2
24) In biochemical systems, the term reduction often refers to
A) a loss of hydrogen or electrons by a compound.
B) a gain of hydrogen or electrons by a compound.
C) a gain in oxygen.
D) a loss of electrons.
E) an energy-releasing reaction.
25) NAD+ stands for the coenzyme
A) niacin adenine dinucleotide.
B) nicotinic acid diphosphate.
C) nicotinamide diphosphate.
D) nicotine adenosine dinucleotide.
E) nicotinamide adenine dinucleotide.
26) NAD+ participates in reactions that produce
A) a CH2 group.
B) a C=O bond.
C) phosphorylation.
D) ADP from ATP.
E) a C-C bond.
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27) FAD stands for
A) flavin adenosine dinucleotide.
B) folic acid diphosphate.
C) fumarate alcohol dehydrogenase.
D) folate adenosine diphosphate.
E) flavin adenine dinucleotide.
28) FAD is a coenzyme which usually participates in
A) oxidation of alcohols to aldehydes.
B) formation of carbon-carbon double bonds.
C) decarboxylation reactions.
D) phosphorylation reactions.
E) β-oxidation reactions.
29) Coenzyme A is a molecule whose function is to
A) activate enzyme A.
B) undergo phosphorylation.
C) provide energy for the citric acid cycle.
D) produce acyl groups for reaction.
E) help break down macromolecules.
30) An acyl group contains at least ________ carbon atom(s).
A) one
B) two
C) three
D) four
E) five
31) The portion of Coenzyme A that reacts with potential substrates is
A) an acid group.
B) an amino group.
C) a C=O group.
D) an alcohol group.
E) a thiol group.
32) Digestion of carbohydrates begins in the
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A) mouth.
B) stomach.
C) pancreas.
D) small intestine.
E) large intestine.
33) An enzyme that can facilitate the breakdown of starch into smaller units is
A) glucose phosphatase.
B) alcohol dehydrogenase.
C) amylase.
D) lactase.
E) maltase.
34) The digestion of carbohydrates goes from
A) glucose to dextrins to maltose.
B) maltose to polysaccharides.
C) polysaccharides to dextrins to glucose.
D) polysaccharides to glucose to dextrins.
E) glucose to polysaccharides.
35) Glycolysis is a(n) ________ process.
A) aerobic
B) anaerobic
C) anabolic
D) one-step
E) five-step
36) In the process of glycolysis, glucose is converted to
A) pyruvate.
B) citrate.
C) sucrose.
D) oxaloacetate.
E) ribose.
37) The overall process of glycolysis
A) requires oxygen.
B) uses up 4 ATP molecules.
C) requires acetyl CoA.
D) is an anabolic pathway.
E) produces 2 ATP molecules.
38) The process of glycolysis is regulated by
A) cell requirements for pyruvate.
B) allosteric control.
C) ATP needs.
D) feedback inhibition.
E) All of the above.
39) Under aerobic conditions, pyruvate produced in glycolysis can be converted to
A) glyceraldehyde-3-phosphate.
B) lactic acid.
C) glucose-6-phosphate.
D) fructose-6-phosphate.
E) acetyl CoA.
40) Which of the following metabolic pathways can occur in the absence of oxygen?
A) electron transport
B) oxidative phosphorylation
C) citric acid cycle
D) glycolysis
E) β-oxidation
41) In step 7 of glycolysis, ATP is generated when a phosphate group is transferred directly from 1,3–
diphosphoglycerate to ADP in a process known as
A) oxidation.
B) direct substrate phosphorylation.
C) reduction.
D) transamination.
E) oxidative phosphorylation.
42) The compounds formed when fructose-1, 6-diphosphate is split are
A) pyruvic acid and lactic acid.
B) ethanol and acetyl CoA.
C) dihydroxyacetone phosphate and pyruvic acid.
D) dihydroxyacetone phosphate and glyceraldehyde 3-phosphate.
E) glyceraldehyde 3-phosphate and pyruvic acid.
43) When one glucose molecule undergoes glycolysis it generates
A) 6 ATP.
B) 6 ATP and 2 NADH.
C) 2 ATP and 2 NADH.
D) 2 ATP and 4 NADH.
E) 12 ATP.
44) Under anaerobic conditions, lactate is produced from
A) acetyl CoA.
B) pyruvate.
C) ATP.
D) carbon dioxide.
E) NAD+.
45) Glycogen is normally stored in
A) heart and lung.
B) liver and muscle.
C) spleen and bone.
D) pancreas and muscle.
E) fat cells and muscle.
46) When as much glycogen is stored as possible in the body, excess glucose is converted to
A) triacylglycerols.
B) fructose.
C) sucrose.
D) Coenzyme A.
E) ATP.
47) The synthesis of glycogen from glucose is called
A) glyceration.
B) gluconeogenesis.
C) glucogenesis.
D) glycogenesis.
E) glycolysis.
48) Glycogenesis obtains energy from
A) ADP.
B) UTP.
C) Pi.
D) pyrophosphate.
E) pyruvate.
49) When glycogen is broken down into glucose, the process is called
A) glycogenesis.
B) glycogenolysis.
C) gluconeogenesis.
D) lactate production.
E) glucagon production.
50) The primary energy source for the brain is
A) lactate.
B) triacylglycerols.
C) amino acids.
D) fructose.
E) glucose.
51) When glucose is made from noncarbohydrate sources, the process is called
A) glycogenesis.
B) glycogenolysis.
C) gluconeogenesis.
D) lactate production.
E) glucagon production.
22.2 Bimodal Questions
1) The term that refers to all of the chemical reactions in living cells is ________.
A) glycolysis
B) β-oxidation
C) metabolism
D) anabolism
E) catabolism
2) Most of the energy in the typical animal cell is produced in the ________.
A) cytosol
B) nucleus
C) mitochondria
D) lysosomes
E) endoplasmic reticulum
3) The energy for most energy-requiring reactions in the cells of the body is obtained by the hydrolysis of
________.
A) ATP
B) ADP
C) AMP
D) cyclic AMP
E) GTP
4) Hydrolysis of sucrose takes place primarily in the ________.
A) mouth
B) stomach
C) pancreas
D) small intestine
E) large intestine
5) The net energy production in anaerobic glycolysis is ________.
A) 2 ATP
B) 4 ATP
C) 6 ATP
D) 8 ATP
E) 12 ATP
6) The production of ethanol from glucose is termed ________.
A) fermentation
B) glycolysis
C) gluconeogenesis
D) β-oxidation
E) dehydrogenation
22.3 True/False Questions
1) Energy production in the cell occurs primarily in the nucleus.
2) The cytosol is an aqueous solution of salts and enzymes.
3) Reactions in the mitochondria produce most of the cell’s energy.
4) Lysosomes digest and recycle old cell structures.
5) Digestion of a polysaccharide is an anabolic process.
6) The production of carbon dioxide and water in the body is an anabolic process.
7) Catabolic reactions provide energy to generate ATP in the cell.
8) ATP is the primary energy source for the cell.
9) The conversion of ATP to ADP and inorganic phosphate produces 7.3 kcal/mole of energy.
10) ATP contains a ribose sugar.
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11) Oxidation involves the gain of electrons for a substance.
12) NAD+ acts as a hydrogen acceptor in metabolic reactions.
13) FADH2 is the oxidized form of FAD.
14) Pantothenic acid is a part of NADH.
15) Digestion of carbohydrates begins in the mouth.
16) Most of the digestion of carbohydrates occurs in the stomach.
17) In glycolysis, two ATPs are invested and six ATPs are synthesized.
18) The product of glycolysis is glucose.
19) Under aerobic conditions, pyruvate is converted to ethanol.
20) In glycogenesis, excess glucose is used to form glycogen.
21) Glycogen storage disease occurs when an enzyme is deficient and impedes the storage or degradation
of glycogen.
22) In gluconeogenesis, glucose is synthesized from noncarbohydrate material.
23) Gluconeogenesis is an anabolic process.
22.4 Matching Questions
Identify each of the following metabolic pathways.
A) the conversion of pyruviate to ethanol and CO2
B) breaking down of macromolecules
C) the synthesis of glycogen from glucose for storage purposes
D) the conversion of glucose to lactic acid
E) the production of glucose from noncarbohydrate molecules
F) lipid metabolism
G) the flow of lactate and glucose between muscle and liver
1) anaerobic glycolysis
Objective: 22.4, 22.5
Global Outcomes: GO2
2) fermentation
Objective: 22.4, 22.5
Global Outcomes: GO2
3) glycogenesis
Objective: 22.4, 22.5
Global Outcomes: GO2
4) gluconeogenesis
Objective: 22.4, 22.5
Global Outcomes: GO2
5) the Cori cycle
Objective: 22.4, 22.5
Global Outcomes: GO2
6) digestion
Objective: 22.4, 22.5
Global Outcomes: GO2
7) triacylglycerol hydrolysis
Objective: 22.4, 22.5
Global Outcomes: GO2