Deck 22: Carbohydrate Metabolism

Question 1

The most important goal of glucose metabolism is

A)synthesis of oxidized coenzymes.
B)synthesis of glycogen for later use.
C)production of ATP as an energy source for all cells.
D)production of acetyl-SCoA for synthesis of lipids.
E)synthesis of carbon skeletons for amino acid production.

Answer 1

production of ATP as an energy source for all cells.

Question 2

The conversion of glucose 6-phosphate to fructose 6-phosphate in the second step of glycolysis is a(an)________ reaction.

A)isomerization
B)reduction
C)oxidation
D)phosphorylation
E)dehydration

Answer 2

isomerization

Question 3

All of the following statements concerning digestion are correct except

A)digestion can be considered a catabolic process in which bulk food is broken down into individual small molecules.
B)the major chemical reaction in digestion is enzyme-catalyzed hydrolysis of large molecules.
C)the major physical processes in digestion are mixing,softening and grinding of food.
D)digestion begins in the stomach and is completed in the large intestine.
E)different foods are digested by different enzymes.

Answer 3

digestion begins in the stomach and is completed in the large intestine.

Question 4

When energy is needed and adequate oxygen is available,pyruvate is converted to ________.

A)glucose
B)glycogen
C)lactate
D)ethanol
E)acetyl-SCoA

Question 5

The target molecule(s)for α-amylase is (are)

A)glucose.
B)sucrose.
C)all disaccharides.
D)starch.
E)starch and glycogen.

Question 6

The major function of the pentose phosphate pathway when energy for anabolic reactions is a priority is

A)producing NADPH.
B)producing ribose.
C)meeting the need for large amounts of ATP.
D)providing intermediates for the citric acid cycle.
E)providing intermediates for glycogenesis.

Question 7

The pathway followed by glucose when energy is needed is

A)gluconeogenesis.
B)glycogenesis.
C)glycolysis.
D)lipogenesis.
E)the pentose phosphate pathway.

Question 8

All of the following statements concerning digestion are correct except

A)the major chemical reaction in digestion is enzyme-catalyzed hydrolysis of large molecules.
B)digestion begins in the mouth,continues in the stomach,and is completed in the small intestine.
C)digestion can be considered a catabolic process in which bulk food is broken down into individual small molecules.
D)the same enzymes are used in the digestion of carbohydrates,lipids,and proteins.
E)the major physical processes in digestion are mixing,softening,and grinding of food.

Question 9

In the first step of glycolysis,the conversion of glucose to glucose 6-phosphate is known as

A)isomerization.
B)reduction.
C)oxidation.
D)phosphorylation.
E)dehydration.

Question 10

Which of the following are produced as a net result of glycolysis?
I.NADH
II.NAD⁺
III.ADP
IV.ATP

A)I and II
B)III and IV
C)I and III
D)I and IV
E)II and III

Question 11

Which conversion is accomplished during glycolysis?

A)glucose to glycogen
B)glucose to pyruvate
C)starch to glucose
D)pyruvate to glucose
E)glycogen to glucose

Question 12

The major products of carbohydrate digestion are

A)monosaccharides and disaccharides
B)monosaccharides
C)acetyl CoA
D)pyruvic acid

Question 13

When a cell's need for NADPH or ribose-6-phosphate exceeds its need for ATP,glucose-6-phosphate is metabolized by

A)gluconeogenesis.
B)glycogenesis.
C)glycolysis.
D)glycogenolysis.
E)the pentose phosphate pathway.

Question 14

Which of the following is not a product of digestion?

A)amino acids
B)fatty acids
C)glucose
D)glycerol
E)pyruvate

Question 15

The major function of the pentose phosphate pathway when nucleic acid synthesis is a priority is

A)producing NADPH.
B)producing ribose.
C)meeting the need for large amounts of ATP.
D)providing intermediates for the citric acid cycle.
E)providing intermediates for glycogenesis.

Question 16

The most important monosaccharide for energy production is

A)glucose.
B)galactose.
C)fructose.
D)ribose.
E)mannose.

Question 17

The chemical resulting from steps 3-5 of glycolysis which is oxidized in step 6 is

A)glucose.
B)acetyl-SCoA.
C)glyceraldehyde 3-phosphate.
D)citrate.
E)oxaloacetate.

Question 18

All of the following are reactions in the oxidation of glucose which produce energy except

A)glycolysis.
B)glycogenolysis.
C)oxidation of pyruvate to acetyl-SCoA.
D)the citric acid cycle.
E)reaction of reduced coenzymes in the electron transport chain.

Question 19

All of the chemicals below are associated with the pentose phosphate pathway except

A)glucose 6-phosphate.
B)NADPH.
C)ribose.
D)pyruvate.
E)NADP.

Question 20

Classify each pathway of carbohydrate metabolism as anabolic or catabolic.Justify your choice in each case.

Question 21

Which of the following carbohydrates can also be used as fuel in glycolysis?

A)glucose
B)glucose and fructose
C)fructose and galactose
D)galactose,fructose,and mannose
E)fructose

Question 22

Which chemical is produced from pyruvate when it is metabolized in muscle cells under anaerobic conditions?

A)lactate
B)ethanol
C)acetyl-SCoA
D)phosphoenol pyruvate
E)glucose

Question 23

The products of glycolysis important in metabolism are

A)acetyl-SCoA and ATP.
B)pyruvate,ATP,and NADH.
C)CO₂,ATP,and NADH.
D)pyruvate,ADP,and NAD⁺.
E)CO₂ and H₂O.

Question 24

The action of yeast on pyruvate is a process referred to as

A)alcoholic fermentation.
B)aerobic oxidation.
C)glycolysis.
D)anaerobic reduction.
E)substrate-level phosphorylation.

Question 25

Insulin increases the rate at which

A)glucose is converted to glycogen.
B)glucose is converted to fat.
C)glucose enters the cell.
D)glucose is converted from glycogen.
E)More than one response is correct.

Question 26

Entry of monosaccharides other than glucose into the glycolysis pathway initially involves

A)breakdown into pyruvate.
B)oxidation into acetyl groups.
C)conversion into phosphates.
D)reduction of carbonyl groups.
E)hydrolysis of 2-carbon units.

Question 27

The first step of glycolysis involves ________ to form ________.

A)esterification; glucose-6-phosphate
B)oxidation; glucose -6-phosphate
C)addition; fructose-1,6-diphosphate
D)esterification; glucose-1-phosphate
E)isomerization; fructose-6-phosphate

Question 28

The enzyme that catalyzes cleavage of fructose 1,6-bisphosphate to dihydroxyacetone phosphate and D-glyceraldehyde-3-phosphate is ________.

A)aldolase
B)D-glyceraldehyde-3-phosphatase
C)phosphofructokinase
D)hexokinase
E)none of the above

Question 29

The overall yield of ATP molecules from the complete catabolism of one molecule of glucose in humans and other mammals is ________.

A)18
B)24
C)32
D)42
E)56

Question 30

When ATP is produced by direct transfer of a phosphate group instead of from reactions coupled to electron transport,the process is referred to as ________ phosphorylation.

A)oxidative
B)substrate-level
C)reductive
D)anabolic
E)catabolic

Question 31

Conversion of dihydroxyacetone phosphate to D-glyceraldehyde 3-phosphate is a(an)________.

A)isomerization
B)oxidation
C)reduction
D)esterification
E)condensation

Question 32

Overproduction of insulin causes ________,a state in which the concentration of blood sugar is ________ than normal.

A)hypoglycemia; lower
B)hypoglycemia; higher
C)hyperglycemia; lower
D)hyperglycemia; higher
E)none of the above

Question 33

The pain and cramps that occur during physical exhaustion are associated with the formation of excess

A)lactate.
B)pyruvate.
C)acetyl-CoA.
D)acetaldehyde.
E)glucose.

Question 34

Glycolysis occurs mainly in the

A)cytosol of all cells.
B)mitochondria of all cells.
C)muscle.
D)liver.
E)brain.

Question 35

Hormones which regulate glucose metabolism are ________,________,and ________.

A)insulin; cortisone; thyroxine
B)insulin; glucagon; epinephrine
C)estrogen; progesterone; testosterone
D)growth hormone; cortisone; thyroxine
E)estrogen; glucagon; epinephrine

Question 36

Which chemical is produced from pyruvate when it is metabolized by yeast cells?

A)lactate
B)ethanol
C)acetyl-SCoA
D)phosphoenol pyruvate
E)glucose

Question 37

Steps 1-5 of glycolysis are referred to as the "energy investment" portion of the process because these steps

A)consume ATP instead of producing it.
B)generate waste products which cost ATP for disposal.
C)produce NADH which is less energy-rich than ATP.
D)involve several endergonic isomerizations.
E)none of the above

Question 38

Pyruvate is converted to lactate under anaerobic conditions because ________.

A)reduction of pyruvate provides NAD⁺ which is needed for glycolysis
B)lactate releases oxygen upon conversion to acetyl-CoA
C)reduction of pyruvate provides NADH which is needed for gluconeogenesis
D)lactate is storage for of pyruvate for use later when more ATP is needed
E)none of the above

Question 39

If a glucose tolerance test shows an abnormally high level of glucose in the blood after several hours,the person is possibly

A)hypoglycemic.
B)diabetic.
C)anemic.
D)overweight.

Question 40

Which chemical is produced from pyruvate when it is metabolized in muscle cells under aerobic conditions?

A)lactate
B)ethanol
C)acetyl-SCoA
D)phosphoenol pyruvate
E)glucose

Question 41

The diseases identified as diabetes are primarily associated with a malfunction of the hormone

A)glucagon.
B)insulin.
C)epinephrine.
D)cortisone.
E)sorbitol.

Question 42

In an individual who is starving or fasting,the body meets its need for glucose first by the process of ________,and then by the process of ________.

A)glycolysis; gluconeogenesis
B)glycogenolysis; gluconeogenesis
C)gluconeogenesis; glycogenesis
D)glycogenesis; lipogenesis
E)lipogenesis; glycogenolysis

Question 43

The process of making glucose from noncarbohydrates is known as

A)glycolysis.
B)glycogenolysis.
C)gluconeogenesis.
D)glycogenesis.
E)lipogenesis.

Question 44

During gluconeogenesis pyruvate is formed from glycerol,certain amino acids and _________.

A)acetyl CoA
B)glucose
C)lactate
D)glycogen

Question 45

When a person is deprived of food,in which order does the body use the following sources to produce glucose?
I.protein breakdown to amino acids used for gluconeogenesis
II.conversion of glycogen to glucose
III.catabolism of lipids

A)I,II,III
B)III,II,I
C)II,I,III
D)II,III,I
E)III,I,II

Question 46

Match the following.
pentose phosphate pathway

A)the conversion of glucose into glycogen
B)the conversion of glucose into carbohydrate molecules containing phosphate
groups and five carbon atoms
C)the production of glucose from noncarbohydrate sources
D)the conversion of glycogen into glucose
E)the conversion of glucose into pyruvate

Question 47

Match the following.
gluconeogenesis

A)the conversion of glucose into glycogen
B)the conversion of glucose into carbohydrate molecules containing phosphate
groups and five carbon atoms
C)the production of glucose from noncarbohydrate sources
D)the conversion of glycogen into glucose
E)the conversion of glucose into pyruvate

Question 48

When blood sugar levels are lower than normal,this condition is called

A)hypoglycemia.
B)hyperglycemia.
C)glucosuria.
D)diabetes mellitus.

Question 49

A lack of insulin causes ________,a state in which the concentration of blood sugar is ________ than normal.

A)hypoglycemia; lower
B)hypoglycemia; higher
C)hyperglycemia; lower
D)hyperglycemia; higher
E)none of the above

Question 50

Match the following.
glycolysis

A)the conversion of glucose into glycogen
B)the conversion of glucose into carbohydrate molecules containing phosphate
groups and five carbon atoms
C)the production of glucose from noncarbohydrate sources
D)the conversion of glycogen into glucose
E)the conversion of glucose into pyruvate

Question 51

Glycogenolysis does not occur in muscle tissue because it lacks which of the following enzymes?

A)glucose-6-phosphatase
B)glycogen phosphorylase
C)phosphoglucomutase
D)pyruvate kinase

Question 52

Glycogen is most commonly found in ________ cells and ________ cells.

A)red blood; white blood
B)red blood; liver
C)muscle; white blood
D)muscle; liver
E)bone; white blood

Question 53

Gluconeogenesis occurs mainly in the

A)cytosol of all cells.
B)mitochondria of all cells.
C)muscle.
D)liver.
E)brain.

Question 54

A high energy phosphate molecule involved in gluconeogenesis is ________.

A)UDP
B)UTP
C)GDP
D)GTP
E)ADP

Question 55

Glycogenolysis can be correctly represented by which of the following pathways?

A)glucose → glycogen
B)glycogen → glucose
C)pyruvate → glycogen
D)glycogen → pyruvate
E)glucose → pyruvate

Question 56

Match the following.
glycogenesis

A)the conversion of glucose into glycogen
B)the conversion of glucose into carbohydrate molecules containing phosphate
groups and five carbon atoms
C)the production of glucose from noncarbohydrate sources
D)the conversion of glycogen into glucose
E)the conversion of glucose into pyruvate

Question 57

Match the following.
glycogenolysis

A)the conversion of glucose into glycogen
B)the conversion of glucose into carbohydrate molecules containing phosphate
groups and five carbon atoms
C)the production of glucose from noncarbohydrate sources
D)the conversion of glycogen into glucose
E)the conversion of glucose into pyruvate

Question 58

Which of the following is not used as an energy source in metabolism?

A)ATP
B)UTP
C)UTC
D)GTP
E)More than one choice is correct.

Question 59

Which pathway converts glucose to its storage form in animals?

A)glycolysis
B)glycogenolysis
C)gluconeogenesis
D)glycogenesis
E)lipogenesis

Question 60

Which pathway produces glucose from its storage form in animals?

A)glycolysis
B)glycogenolysis
C)gluconeogenesis
D)glycogenesis
E)lipogenesis