Test 4 Flashcards by Aamna Qandil

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

True

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

Oxidative

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

All of the above

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

Liver

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

Glucagon

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

Pyruvate carboxylase

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

Acetyl-CoA

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Gluconeogenesis occurs mainly in the ________.

Liver

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

Pyruvate carboxylase

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Gluconeogenesis is an energy ________ process.

Energy-consuming

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Gluconeogenesis is the reverse pathway of ________.

Glycolysis

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

Fructose-6-phosphate

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Gluconeogenesis primarily occurs in the mitochondria. True or false?

False

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Gluconeogenesis is an anabolic process. True or false?

True

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

True

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

True

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

True

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

Fermentation

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

Pyruvate

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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

Glucose-6-phosphatase

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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

Enhancing gluconeogenesis

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

Glycogenesis

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

Hexokinase

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

Mitochondria

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Glycogen is primarily stored in the ________ and ________ tissues.

Liver and muscle

The rate-limiting enzyme in glycolysis is ________.

Phosphofructokinase

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

Glycogen phosphorylase

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

Jejunum

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

All of the above

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

Facilitated diffusion

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

SGLT1

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

GLUT5

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

SGLT1

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

GLUT2

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

Sodium (Na+)

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

Hepatic portal vein

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

True

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

False

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

False

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

True

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

Synthesizing glycogen from glucose

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

Muscles

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

Glycogen synthase

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

Glucose-1-phosphate

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

Insulin

Glycogenesis occurs in response to ________ blood glucose levels.

high/elevated

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

glycogen synthase

Glycogenin serves as the ________ for glycogen synthesis.

primer

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

cytoplasm

Glycogenesis is regulated by the ________ enzyme.

glycogen synthase

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

False

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

True

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

True

Glycogenolysis and glycogenesis are opposing processes. True or false?

True

Glycogen synthesis requires ATP. True or false?

True

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

Cytoplasm

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

Pyruvate

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

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

Hexokinase

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

Substrate-level phosphorylation

Glycolysis begins with the phosphorylation of glucose to form ________.

glucose-6-phosphate

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

glyceraldehyde-3-phosphate dehydrogenase

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

Glycolysis requires oxygen as a substrate. True or false?

False

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

False

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

True

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

True

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

True

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

False

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

True

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

Glycolysis

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

Generate reducing equivalents (NADPH)

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

Cytoplasm

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

Oxidative phase

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

Glucose-6-phosphate dehydrogenase

The oxidative phase of the pentose phosphate pathway generates ________.

NADPH

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

pentose, hexose

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

phosphopentose isomerase

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

ribose-5-phosphate

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

transketolase

The pentose phosphate pathway produces ATP. True or false?

False

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

False

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

True

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

True

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

True

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

True

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

True

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

True

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

False

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

False

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

Intermediates that carry reducing equivalents

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

Malate-aspartate, citrate

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

Mitochondria

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

Mitochondrial matrix

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

FADH2

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

NADH

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

malate

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

citrate

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

citrate

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

oxaloacetate