Test 4 Flashcards

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1
Q

The pentose phosphate pathway occurs exclusively in the cytoplasm of cells. True or false?

A

True

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2
Q

The first phase of the pentose phosphate pathway is called the __________ phase.
a) Oxidative
b) Non-oxidative
c) Glycolytic
d) Reductive

A

Oxidative

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3
Q

Gluconeogenesis is the process of synthesizing glucose from:
a) Amino acids
b) Fatty acids
c) Glycogen
d) All of the above

A

All of the above

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4
Q

Which of the following organs primarily carries out gluconeogenesis?
a) Liver
b) Kidneys
c) Pancreas
d) Stomach

A

Liver

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5
Q

Gluconeogenesis is stimulated by the hormone:
a) Insulin
b) Glucagon
c) Estrogen
d) Testosterone

A

Glucagon

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6
Q

The rate-limiting enzyme in gluconeogenesis is:
a) Hexokinase
b) Phosphofructokinase
c) Glucose-6-phosphatase
d) Pyruvate carboxylase

A

Pyruvate carboxylase

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7
Q

Which of the following is NOT a precursor for gluconeogenesis?
a) Pyruvate
b) Lactate
c) Acetyl-CoA
d) Oxaloacetate

A

Acetyl-CoA

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8
Q

Gluconeogenesis occurs mainly in the ________.

A

Liver

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9
Q

The conversion of pyruvate to oxaloacetate is catalyzed by the enzyme ________.

A

Pyruvate carboxylase

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10
Q

Gluconeogenesis is an energy ________ process.

A

Energy-consuming

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11
Q

Gluconeogenesis is the reverse pathway of ________.

A

Glycolysis

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12
Q

In gluconeogenesis, fructose-1,6-bisphosphate is converted to ________.

A

Fructose-6-phosphate

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13
Q

Gluconeogenesis primarily occurs in the mitochondria. True or false?

A

False

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14
Q

Gluconeogenesis is an anabolic process. True or false?

A

True

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15
Q

Gluconeogenesis is the main pathway for glucose synthesis during fasting. True or false?

A

True

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16
Q

Gluconeogenesis can be inhibited by high levels of insulin. True or false?

A

True

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17
Q

Gluconeogenesis produces glucose from non-carbohydrate sources. True or false?

A

True

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18
Q

The process by which glucose is converted to pyruvate in the absence of oxygen is called:
a) Glycolysis
b) Gluconeogenesis
c) Glycogenolysis
d) Fermentation

A

Fermentation

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19
Q

The end product of glycolysis is:
a) Pyruvate
b) Acetyl-CoA
c) Oxaloacetate
d) Lactate

A

Pyruvate

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20
Q

Which enzyme is responsible for converting glucose-6-phosphate to glucose in the liver during glycogenolysis?
a) Glucose-6-phosphatase
b) Hexokinase
c) Phosphofructokinase
d) Pyruvate carboxylase

A

Glucose-6-phosphatase

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21
Q

Which of the following is NOT a function of insulin in carbohydrate metabolism?
a) Promoting glucose uptake in cells
b) Inhibiting glycogenolysis
c) Stimulating glycolysis
d) Enhancing gluconeogenesis

A

Enhancing gluconeogenesis

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22
Q

The process of converting excess glucose into glycogen for storage is known as:
a) Glycogenolysis
b) Gluconeogenesis
c) Glycogenesis
d) Fermentation

A

Glycogenesis

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23
Q

The first step of glycolysis is the phosphorylation of glucose by the enzyme ________.

A

Hexokinase

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24
Q

In the presence of oxygen, pyruvate enters the ________ where it is converted to acetyl-CoA.

A

Mitochondria

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25
Q

Glycogen is primarily stored in the ________ and ________ tissues.

A

Liver and muscle

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26
Q

The rate-limiting enzyme in glycolysis is ________.

A

Phosphofructokinase

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27
Q

The breakdown of glycogen into glucose-1-phosphate is catalyzed by the enzyme ________.

A

Glycogen phosphorylase

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28
Q

The majority of monosaccharide absorption in the small intestine occurs in the:
a) Duodenum
b) Jejunum
c) Ileum
d) Colon

A

Jejunum

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29
Q

Which of the following monosaccharides is primarily absorbed in the small intestine?
a) Glucose
b) Fructose
c) Galactose
d) All of the above

A

All of the above

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30
Q

Monosaccharides are transported across the apical membrane of enterocytes by:
a) Active transport
b) Passive diffusion
c) Facilitated diffusion
d) Endocytosis

A

Facilitated diffusion

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31
Q

The transport protein responsible for glucose and galactose absorption is called:
a) SGLT1
b) GLUT2
c) GLUT5
d) SGLT2

A

SGLT1

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32
Q

Fructose absorption in the small intestine is facilitated by the transporter:
a) SGLT1
b) GLUT2
c) GLUT5
d) SGLT2

A

GLUT5

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33
Q

Glucose and galactose are absorbed in the small intestine by the ________ transporter.

A

SGLT1

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34
Q

After absorption, monosaccharides are transported across the basolateral membrane of enterocytes by the transporter ________.

A

GLUT2

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35
Q

Monosaccharide absorption is driven by the ________ gradient established by Na+/K+ ATPase.

A

Sodium (Na+)

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36
Q

Once absorbed, monosaccharides enter the ________ and are transported to the liver.

A

Hepatic portal vein

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37
Q

Monosaccharides are absorbed in their monomeric form in the small intestine. True or false?

A

True

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38
Q

The absorption of monosaccharides requires the presence of digestive enzymes. True or false?

A

False

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39
Q

Fructose is primarily absorbed by active transport in the small intestine. True or false?

A

False

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40
Q

Monosaccharide absorption occurs through the epithelial cells of the intestinal villi. True or false?

A

True

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41
Q

Glycogenesis is the process of:
a) Breaking down glycogen into glucose
b) Synthesizing glycogen from glucose
c) Converting glucose into pyruvate
d) Transforming fatty acids into glucose

A

Synthesizing glycogen from glucose

42
Q

The primary site of glycogen storage in the body is the:
a) Liver
b) Muscles
c) Adipose tissue
d) Pancreas

A

Muscles

43
Q

The rate-limiting enzyme in glycogenesis is:
a) Glycogen phosphorylase
b) Glycogen synthase
c) Glucose-6-phosphatase
d) Phosphofructokinase

A

Glycogen synthase

44
Q

The activated form of glucose used in glycogenesis is:
a) Glucose-1-phosphate
b) Glucose-6-phosphate
c) Fructose-6-phosphate
d) Glucose-1,6-bisphosphate

A

Glucose-1-phosphate

45
Q

Which of the following hormones stimulates glycogen synthesis?
a) Insulin
b) Glucagon
c) Epinephrine
d) Cortisol

A

Insulin

46
Q

Glycogenesis occurs in response to ________ blood glucose levels.

A

high/elevated

47
Q

The enzyme ________ is responsible for adding glucose units to the growing glycogen chain during glycogenesis.

A

glycogen synthase

48
Q

Glycogenin serves as the ________ for glycogen synthesis.

A

primer

49
Q

Glycogen is stored in the form of granules in the ________.

A

cytoplasm

50
Q

Glycogenesis is regulated by the ________ enzyme.

A

glycogen synthase

51
Q

Glycogen is primarily stored in the form of glycogenin. True or false?

A

False

52
Q

Glycogen synthase adds glucose units to the non-reducing ends of the glycogen molecule. True or false?

A

True

53
Q

The enzyme glycogen phosphorylase breaks down glycogen into glucose-6-phosphate. True or false?

A

True

54
Q

Glycogenolysis and glycogenesis are opposing processes. True or false?

A

True

55
Q

Glycogen synthesis requires ATP. True or false?

A

True

56
Q

Glycolysis is a metabolic pathway that occurs in the:
a) Mitochondria
b) Nucleus
c) Cytoplasm
d) Endoplasmic reticulum

A

Cytoplasm

57
Q

The end product of glycolysis is:
a) Pyruvate
b) Acetyl-CoA
c) Oxaloacetate
d) Lactate

A

Pyruvate

58
Q

How many ATP molecules are produced directly during glycolysis?
a) 1
b) 2
c) 3
d) 4

A

2

59
Q

The enzyme responsible for the phosphorylation of glucose to glucose-6-phosphate is:
a) Phosphofructokinase
b) Hexokinase
c) Pyruvate kinase
d) Aldolase

A

Hexokinase

60
Q

In the energy payoff phase of glycolysis, ATP is generated by:
a) Substrate-level phosphorylation
b) Oxidative phosphorylation
c) Glycolytic phosphorylation
d) Photophosphorylation

A

Substrate-level phosphorylation

61
Q

Glycolysis begins with the phosphorylation of glucose to form ________.

A

glucose-6-phosphate

62
Q

The enzyme ________ catalyzes the conversion of glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate.

A

glyceraldehyde-3-phosphate dehydrogenase

63
Q

In the energy payoff phase, ________ molecules of ATP are generated.

A

4

64
Q

Glycolysis requires oxygen as a substrate. True or false?

A

False

65
Q

NADH is produced during the conversion of 3-phosphoglycerate to 2-phosphoglycerate. True or false?

A

False

66
Q

Glycolysis is the initial step in both aerobic and anaerobic respiration. True or false?

A

True

67
Q

The enzyme enolase catalyzes the conversion of 2-phosphoglycerate to phosphoenolpyruvate. True or false?

A

True

68
Q

The conversion of 1,3-bisphosphoglycerate to 3-phosphoglycerate is coupled with the production of ATP. True or false?

A

True

69
Q

ATP is consumed during the conversion of fructose-1,6-bisphosphate to fructose-6-phosphate. True or false?

A

False

70
Q

The glycolytic pathway consists of 10 enzymatic reactions. True or false?

A

True

71
Q

The pentose phosphate pathway is an alternative metabolic pathway that occurs alongside:
a) Glycolysis
b) Glycogenesis
c) Gluconeogenesis
d) Krebs cycle

A

Glycolysis

72
Q

The primary function of the pentose phosphate pathway is to:
a) Generate ATP
b) Produce NADH
c) Generate reducing equivalents (NADPH)
d) Convert glucose into pyruvate

A

Generate reducing equivalents (NADPH)

73
Q

The pentose phosphate pathway occurs predominantly in which cellular compartment?
a) Cytoplasm
b) Nucleus
c) Mitochondria
d) Endoplasmic reticulum

A

Cytoplasm

74
Q

The first phase of the pentose phosphate pathway is called the:
a) Oxidative phase
b) Non-oxidative phase
c) Reductive phase
d) Glycolytic phase

A

Oxidative phase

75
Q

The key enzyme that initiates the oxidative phase of the pentose phosphate pathway is:
a) Glucose-6-phosphate dehydrogenase
b) Ribulose-5-phosphate epimerase
c) Transketolase
d) Transaldolase

A

Glucose-6-phosphate dehydrogenase

76
Q

The oxidative phase of the pentose phosphate pathway generates ________.

A

NADPH

77
Q

The non-oxidative phase of the pentose phosphate pathway involves the interconversion of ________ and ________.

A

pentose, hexose

78
Q

The enzyme ________ is responsible for the interconversion of ribose-5-phosphate and ribulose-5-phosphate.

A

phosphopentose isomerase

79
Q

The pentose phosphate pathway is important for providing ________ for nucleotide synthesis.

A

ribose-5-phosphate

80
Q

The enzyme ________ is involved in both the oxidative and non-oxidative phases of the pentose phosphate pathway.

A

transketolase

81
Q

The pentose phosphate pathway produces ATP. True or false?

A

False

82
Q

NADH is generated during the oxidative phase of the pentose phosphate pathway. True or false?

A

False

83
Q

Glucose-6-phosphate dehydrogenase is the rate-limiting enzyme of the pentose phosphate pathway. True or false?

A

True

84
Q

The pentose phosphate pathway produces NADPH through the reduction of NADP+. True or false?

A

True

85
Q

The non-oxidative phase of the pentose phosphate pathway involves the conversion of pentose sugars into hexose sugars. True or false?

A

True

86
Q

Ribose-5-phosphate is a precursor for the synthesis of nucleotides. True or false?

A

True

87
Q

The pentose phosphate pathway is regulated by the availability of glucose-6-phosphate. True or false?

A

True

88
Q

The pentose phosphate pathway is important for the detoxification of reactive oxygen species (ROS). True or false?

A

True

89
Q

The pentose phosphate pathway is the primary pathway for glucose metabolism in all tissues. True or false?

A

False

90
Q

The pentose phosphate pathway is an anaerobic pathway. True or false?

A

False

91
Q

Shuttles in glycolysis refer to:
a) Transport proteins
b) Enzymes that catalyze reactions
c) Intermediates that carry reducing equivalents
d) Cellular compartments involved in glycolysis

A

Intermediates that carry reducing equivalents

92
Q

The two main shuttles involved in glycolysis are the ________ and ________ shuttles.
a) Malate-aspartate, citrate
b) NADH, FADH2
c) Glyceraldehyde-3-phosphate, pyruvate
d) Acetyl-CoA, oxaloacetate

A

Malate-aspartate, citrate

93
Q

The malate-aspartate shuttle operates primarily in the:
a) Cytoplasm
b) Mitochondria
c) Nucleus
d) Endoplasmic reticulum

A

Mitochondria

94
Q

In the malate-aspartate shuttle, NADH is oxidized to NAD+ in the ________ compartment.
a) Cytoplasm
b) Mitochondrial matrix
c) Intermembrane space
d) Nucleus

A

Mitochondrial matrix

95
Q

The citrate shuttle involves the transport of reducing equivalents in the form of ________ between the cytoplasm and mitochondria.
a) NADH
b) FADH2
c) ATP
d) GTP

A

FADH2

96
Q

The malate-aspartate shuttle transfers reducing equivalents in the form of ________.

A

NADH

97
Q

In the malate-aspartate shuttle, oxaloacetate is reduced to ________ in the cytoplasm.

A

malate

98
Q

The ________ shuttle transfers reducing equivalents from cytoplasmic NADH to FADH2 in the mitochondria.

A

citrate

99
Q

In the citrate shuttle, cytoplasmic acetyl-CoA is transported into the mitochondria in the form of ________.

A

citrate

100
Q

The final step of the citrate shuttle involves the conversion of citrate back to ________ and acetyl-CoA in the mitochondria.

A

oxaloacetate