Question 1

What types of reactions are involved in the two-step conversion of glucose to fructose?

Accepted Answer

A) Reduction followed by oxidation. 
B) Two sequential hydrolysis reactions. 
C) Hydrolysis followed by isomerization (rearrangement). 
D) Phosphorylation followed by dephosphorylation. 
A) Reduction followed by oxidation. 
B) Two sequential hydrolysis reactions. 
C) Hydrolysis followed by isomerization (rearrangement). 
D) Phosphorylation followed by dephosphorylation.

Question 2

The sequence of glucose conversion to lactate in peripheral tissues,delivery of lactate to the liver,formation of glucose from lactate in the liver,and delivery of glucose back to peripheral tissues is known as the ________.

Accepted Answer

A) glyoxylate cycle 
B) Kreb's cycle 
C) Cori cycle 
D) gluconeogenesis cycle 
A) glyoxylate cycle 
B) Kreb's cycle 
C) Cori cycle 
D) gluconeogenesis cycle

Question 3

Like most metabolic diseases,glycogen storage diseases are results from genetic defects in essential genes.

Accepted Answer

A) True 
 B)False

Question 4

Glucagon is excreted when blood glucose is ________ (high,low),while insulin is secreted when blood glucose is ________ (high,low).

Accepted Answer

A) high;high 
B) high;low 
C) low;low 
D) low;high 
A) high;high 
B) high;low 
C) low;low 
D) low;high

Question 5

The ________ is the site of most gluconeogenesis in mammals.

Accepted Answer

A) liver 
B) pancreas 
C) cytosol of all cells 
D) small intestine 
A) liver 
B) pancreas 
C) cytosol of all cells 
D) small intestine

Question 6

Glycerol is converted to ________ when it is used for gluconeogenesis.

Accepted Answer

A) dihydroxyacetone phosphate 
B) phosphoenolpyruvate 
C) oxaloacetate 
D) 3-phosphoglycerate 
A) dihydroxyacetone phosphate 
B) phosphoenolpyruvate 
C) oxaloacetate 
D) 3-phosphoglycerate

Question 7

Glycogenin is

Accepted Answer

A) a protein for attachment of primer glucose chains. 
B) an enzyme that attaches glucose residues to a growing chain. 
C) a pre-existing primer in glycogen synthesis. 
D) A and B. 
A) a protein for attachment of primer glucose chains. 
B) an enzyme that attaches glucose residues to a growing chain. 
C) a pre-existing primer in glycogen synthesis. 
D) A and B.

Question 8

Gluconeogenesis is the ________.

Accepted Answer

A) result of amylase activity 
B) formation of glycogen 
C) formation of starches 
D) formation of glucose from simple two and three-carbon precursors 
E) formation of glucose from other carbohydrates 
A) result of amylase activity 
B) formation of glycogen 
C) formation of starches 
D) formation of glucose from simple two and three-carbon precursors 
E) formation of glucose from other carbohydrates

Question 9

The reaction catalyzed by polyol dehydrogenase involves the reduction of sorbitol.

Accepted Answer

A) True 
 B)False

Question 10

The non-oxidative stage of the pentose phosphate pathway ________.

Accepted Answer

A) produces NADPH and releases CO² 
B) consists entirely of near-equilibrium reactions 
C) contains two reactions whose enzymes are allosterically inhibited by NADPH 
D) consumes four ATP molecules 
A) produces NADPH and releases CO² 
B) consists entirely of near-equilibrium reactions 
C) contains two reactions whose enzymes are allosterically inhibited by NADPH 
D) consumes four ATP molecules

Question 11

When ATP levels are high,glycolysis is (stimulated,reduced)________,and when AMP levels are high gluconeogenesis is (stimulated,reduced)________.

Accepted Answer

A) stimulated;reduced 
B) stimulated;stimulated 
C) reduced;reduced 
D) reduced;stimulated 
A) stimulated;reduced 
B) stimulated;stimulated 
C) reduced;reduced 
D) reduced;stimulated

Question 12

The pentose phosphate pathway can alternatively be called the pentose phosphate cycle because ________ is a net product of the pathway that can be recycled.

Accepted Answer

A) glucose 6-phosphate 
B) NADP+ 
C) carbon dioxide 
D) phosphate 
E) UDP 
A) glucose 6-phosphate 
B) NADP+ 
C) carbon dioxide 
D) phosphate 
E) UDP

Question 13

UDP-glucose is a precursor of glycogen in all cells.

Accepted Answer

A) True 
 B)False

Question 14

Gluconeogenesis shares some,but not all,enzymes with the glycolytic pathway.It would appear to be more efficient if both pathways used all of the same enzymes since the pathways are essentially the reverses of each other.Why don't both pathways use all of the same enzymes?

Accepted Answer

A) The reactions where enzymes differ occur in different parts of the cell for glycolysis versus gluconeogenesis. 
B) Enzymes can catalyze a reaction only in one direction,so naturally the two pathways have some enzymes that differ. 
C) In tissues where gluconeogenesis occurs,the glycolytic enzymes are present at extremely low concentrations. 
D) Three of the reaction steps in gluconeogenesis would have prohibitively large,positive free energies if they used glycolytic enzymes for their catalysis. 
A) The reactions where enzymes differ occur in different parts of the cell for glycolysis versus gluconeogenesis. 
B) Enzymes can catalyze a reaction only in one direction,so naturally the two pathways have some enzymes that differ. 
C) In tissues where gluconeogenesis occurs,the glycolytic enzymes are present at extremely low concentrations. 
D) Three of the reaction steps in gluconeogenesis would have prohibitively large,positive free energies if they used glycolytic enzymes for their catalysis.

Question 15

Since caffeine inhibits cAMP phosphodiesterase,too much coffee can result in the synthesis of too much glycogen.

Accepted Answer

A) True 
 B)False

Question 16

Fragments containing three carbons can be transferred from a ketose phosphate to an aldose phosphate by the enzyme ________.

Accepted Answer

A) pyruvate carboxylase 
B) transaldolase 
C) debranching enzyme 
D) ribose-5-phosphate isomerase 
A) pyruvate carboxylase 
B) transaldolase 
C) debranching enzyme 
D) ribose-5-phosphate isomerase

Question 17

Fructose 2,6-bisphosphate ________ glycolysis while it ________ gluconeogenesis.

Accepted Answer

A) stimulates;stimulates 
B) stimulates;inhibits 
C) inhibits;stimulates 
D) inhibits;inhibits 
A) stimulates;stimulates 
B) stimulates;inhibits 
C) inhibits;stimulates 
D) inhibits;inhibits

Question 18

Glycogen synthesis in vertebrates requires ________ to activate glucose 1-phosphate.

Accepted Answer

A) ATP 
B) ADP 
C) UTP 
D) UDP 
E) All of the above 
A) ATP 
B) ADP 
C) UTP 
D) UDP 
E) All of the above

Question 19

The enzymes transketolase and transaldolase of the pentose phosphate pathway are each very specific for only one substrate.

Accepted Answer

A) True 
 B)False

Question 20

What is a cause of cataracts in the eye lens of individuals with diabetes?

Accepted Answer

A) Accumulation of sorbitol and protein precipitation in the lens. 
B) Precipitation of glucose not oxidized by glycolysis in the lens. 
C) The absence of membrane transport proteins for pyruvate in the lens cells. 
D) Lack of regulation of gluconeogenesis in the lens and the accumulation of fructose. 
A) Accumulation of sorbitol and protein precipitation in the lens. 
B) Precipitation of glucose not oxidized by glycolysis in the lens. 
C) The absence of membrane transport proteins for pyruvate in the lens cells. 
D) Lack of regulation of gluconeogenesis in the lens and the accumulation of fructose.

Exam 12: Gluconeogenesis, the Pentose Phosphate Pathway, and Glycogen Metabolism

What types of reactions are involved in the two-step conversion of glucose to fructose?

The sequence of glucose conversion to lactate in peripheral tissues,delivery of lactate to the liver,formation of glucose from lactate in the liver,and delivery of glucose back to peripheral tissues is known as the ________.

Like most metabolic diseases,glycogen storage diseases are results from genetic defects in essential genes.

Glucagon is excreted when blood glucose is ________ (high,low),while insulin is secreted when blood glucose is ________ (high,low).

The ________ is the site of most gluconeogenesis in mammals.

Glycerol is converted to ________ when it is used for gluconeogenesis.

Glycogenin is

Gluconeogenesis is the ________.

The reaction catalyzed by polyol dehydrogenase involves the reduction of sorbitol.

The non-oxidative stage of the pentose phosphate pathway ________.

When ATP levels are high,glycolysis is (stimulated,reduced)________,and when AMP levels are high gluconeogenesis is (stimulated,reduced)________.

The pentose phosphate pathway can alternatively be called the pentose phosphate cycle because ________ is a net product of the pathway that can be recycled.

UDP-glucose is a precursor of glycogen in all cells.

Gluconeogenesis shares some,but not all,enzymes with the glycolytic pathway.It would appear to be more efficient if both pathways used all of the same enzymes since the pathways are essentially the reverses of each other.Why don't both pathways use all of the same enzymes?

Since caffeine inhibits cAMP phosphodiesterase,too much coffee can result in the synthesis of too much glycogen.

Fragments containing three carbons can be transferred from a ketose phosphate to an aldose phosphate by the enzyme ________.

Fructose 2,6-bisphosphate ________ glycolysis while it ________ gluconeogenesis.

Glycogen synthesis in vertebrates requires ________ to activate glucose 1-phosphate.

The enzymes transketolase and transaldolase of the pentose phosphate pathway are each very specific for only one substrate.

What is a cause of cataracts in the eye lens of individuals with diabetes?

Introduction to Biochemistry

Water

Amino Acids and the Primary Structures of Proteins

Proteins: Three-Dimensional Structure and Function

Properties of Enzymes

Mechanisms of Enzymes

Coenzymes and Vitamins

Carbohydrates

Lipids and Membranes

Introduction to Metabolism

Glycolysis

The Citric Acid Cycle

Electron Transport and Atp Synthesis

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Nucleotide Metabolism

Nucleic Acids

DNA Replication, repair, and Recombination

Transcription and RNA Processing

Protein Synthesis

Filters

Glucagon is excreted when blood glucose is (high,low),while insulin is secreted when blood glucose is (high,low).

When ATP levels are high,glycolysis is (stimulated,reduced),and when AMP levels are high gluconeogenesis is (stimulated,reduced).

Fructose 2,6-bisphosphate glycolysis while it gluconeogenesis.