Question 1

All are true for α-amylase EXCEPT:

Accepted Answer

A)  catalyzes hydrolysis of α (1→4) linkages in starch. 
B)  is an important component of saliva and pancreatic juice. 
C)  catalyzes hydrolysis of α (1→6) linkages in amylopectin. 
D)  catalyzes hydrolysis of α (1→4) linkages in glycogen. 
E)  activity is reduced in highly branched regions of polysaccharides and stops four residues from any branch point. 
A)  catalyzes hydrolysis of α (1→4) linkages in starch. 
B)  is an important component of saliva and pancreatic juice. 
C)  catalyzes hydrolysis of α (1→6) linkages in amylopectin. 
D)  catalyzes hydrolysis of α (1→4) linkages in glycogen. 
E)  activity is reduced in highly branched regions of polysaccharides and stops four residues from any branch point. C

Question 2

Glucose monitoring devices use the reaction, Glucose + O2 + H2O → gluconate + 2 ____, which is catalyzed by the enzyme ____.

Accepted Answer

A)  H2O; glucose hydrolase 
B)  H2O; glucose oxidase 
C)  H2O2; peroxidase 
D)  H2O2; glucose oxidase 
E)  H2O; gluconate synthase 
A)  H2O; glucose hydrolase 
B)  H2O; glucose oxidase 
C)  H2O2; peroxidase 
D)  H2O2; glucose oxidase 
E)  H2O; gluconate synthase D

Question 3

When a cell with the pentose phosphate pathway has need for more pentose phosphates, but no additional NADPH:

Accepted Answer

A)  glucose-6-phosphate dehydrogenase is activated. 
B)  the oxidative and non-oxidative enzymes of the pentose phosphate pathway are active. 
C)  the non-oxidative enzymes produce pentose phosphates from fructose-6-phosphate and glyceraldehyde-3-phosphate. 
D)  all enzymes of glycolysis and pentose phosphate pathway are active. 
E)  none are true. 
A)  glucose-6-phosphate dehydrogenase is activated. 
B)  the oxidative and non-oxidative enzymes of the pentose phosphate pathway are active. 
C)  the non-oxidative enzymes produce pentose phosphates from fructose-6-phosphate and glyceraldehyde-3-phosphate. 
D)  all enzymes of glycolysis and pentose phosphate pathway are active. 
E)  none are true. C

Question 4

If both NADPH and ribose-5-P are needed which of the following best represents the net reaction of the pentose phosphate pathway?

Accepted Answer

A)  4 Fruc-6-P + 2 glyceraldehyde-3-P → 6 ribose-5-P 
B)  3 Gluc-6-P + 6 NADP+ → 6 NADPH + 3 CO2 + 2 Fruc-6-P + 1 glyceraldehyde-3-P + 6 H+ 
C)  Gluc-6-P + 2 NADP+ + 2 H2O → 2 NADPH + CO2 + ribose-5-P + 2 H+ 
D)  Gluc-6-P + 12 NADP+ + 6 H2O → 1 2 NADPH + 6 CO2 + 12 H+ + Pi 
E)  None of the above 
A)  4 Fruc-6-P + 2 glyceraldehyde-3-P → 6 ribose-5-P 
B)  3 Gluc-6-P + 6 NADP+ → 6 NADPH + 3 CO2 + 2 Fruc-6-P + 1 glyceraldehyde-3-P + 6 H+ 
C)  Gluc-6-P + 2 NADP+ + 2 H2O → 2 NADPH + CO2 + ribose-5-P + 2 H+ 
D)  Gluc-6-P + 12 NADP+ + 6 H2O → 1 2 NADPH + 6 CO2 + 12 H+ + Pi 
E)  None of the above

Question 5

The appropriate sequence for the transketolase catalyzed reaction would be:
A.reactive enamine attack on the aldehyde group of an aldose
B.β-cleavage of Schiff base intermediate to release an aldose
C.formation of Schiff base intermediate of a new ketose
D.active site lysine forms Schiff base with keto-carbonyl group
E.Schiff base hydrated to ketose and enzyme

Accepted Answer

A)  C, A, B, D, E 
B)  D, B, A, C, E, 
C)  D, A, B, E, C 
D)  A, D, B, C, E 
E)  E, D, C, B, A 
A)  C, A, B, D, E 
B)  D, B, A, C, E, 
C)  D, A, B, E, C 
D)  A, D, B, C, E 
E)  E, D, C, B, A

Question 6

Which of the following reactions is catalyzed by a transketolase in the pentose phosphate pathway?
I.
Fructose-6-P + glyceraldehyde-3-P ⇔ xylulose-5-P + erythrose-4-P
II.
Erythrose-4-P + fructose-6-P ⇔ sedoheptulose-7-P + glyceraldehyde-3-P
III.
Sedoheptulose-7-P + glyceraldehyde-3-P ⇔ ribose-5-P + xyulose-5-P

Accepted Answer

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

Question 7

In the gluconeogenic pathway, the three regulated reactions of glycolysis catalyzed by ____, ____ and ____ are replaced by alternative reactions.

Accepted Answer

A)  glucokinase; PFK-1; pyruvate kinase 
B)  phosphoglucoisomerase; PFK-1; pyruvate kinase 
C)  PFK-1; triose phosphate isomerase; pyruvate kinase 
D)  glucokinase; PFK-1; glyceraldehyde-3-phosphate dehydrogenase 
E)  glucokinase; PFK-1; pyruvate carboxylase 
A)  glucokinase; PFK-1; pyruvate kinase 
B)  phosphoglucoisomerase; PFK-1; pyruvate kinase 
C)  PFK-1; triose phosphate isomerase; pyruvate kinase 
D)  glucokinase; PFK-1; glyceraldehyde-3-phosphate dehydrogenase 
E)  glucokinase; PFK-1; pyruvate carboxylase

Question 8

Which of the following can be used as a substrate for gluconeogenesis in the liver?

Accepted Answer

A)  alanine 
B)  glutamic acid 
C)  glycerol 
D)  succinate 
E)  all of the above 
A)  alanine 
B)  glutamic acid 
C)  glycerol 
D)  succinate 
E)  all of the above

Question 9

The polyol pathway is a suspected pathway for diabetic induced cataract formation and involves the enzyme:

Accepted Answer

A)  aldose reductase. 
B)  glucose-6-phosphate dehydrogenase. 
C)  phosphopentose isomerase. 
D)  phosphopentose epimerase. 
E)  transaldolase. 
A)  aldose reductase. 
B)  glucose-6-phosphate dehydrogenase. 
C)  phosphopentose isomerase. 
D)  phosphopentose epimerase. 
E)  transaldolase.

Question 10

Characteristics of glucose-6-phosphate dehydrogenase include all EXCEPT:

Accepted Answer

A)  located in the mitochondria. 
B)  strongly inhibited by [NADPH]. 
C)  inhibited by fatty acid-CoA. 
D)  uses NADP+ as a coenzyme. 
E)  forms a cyclic ester (lactone) of 6-phosphogluconate. 
A)  located in the mitochondria. 
B)  strongly inhibited by [NADPH]. 
C)  inhibited by fatty acid-CoA. 
D)  uses NADP+ as a coenzyme. 
E)  forms a cyclic ester (lactone) of 6-phosphogluconate.

Question 11

An individual with von Gierke's disease lacks the enzyme ____ which is a liver enzyme used to maintain ____. As a result, the patient is ____.

Accepted Answer

A)  glycogen synthase; liver glycogen; fat 
B)  glycogen synthase; ATP levels; weak 
C)  phosphoprotein phosphatase-1; blood glucose; hypoglycemic 
D)  glucose-6-phosphatase; blood glucose; hypoglycemic 
E)  glucose-6-phosphatase; muscle glycogen; weak 
A)  glycogen synthase; liver glycogen; fat 
B)  glycogen synthase; ATP levels; weak 
C)  phosphoprotein phosphatase-1; blood glucose; hypoglycemic 
D)  glucose-6-phosphatase; blood glucose; hypoglycemic 
E)  glucose-6-phosphatase; muscle glycogen; weak

Question 12

Which of the following occurs as a result of cortisol release from the adrenal gland?

Accepted Answer

A)  activation of gluconeogenesis 
B)  increased glycogen synthesis 
C)  activation of the urea cycle 
D)  increased degradation of muscle protein 
E)  all of the above 
A)  activation of gluconeogenesis 
B)  increased glycogen synthesis 
C)  activation of the urea cycle 
D)  increased degradation of muscle protein 
E)  all of the above

Question 13

All are substrates for gluconeogenesis EXCEPT:

Accepted Answer

A)  glycerol. 
B)  lactate. 
C)  acetate. 
D)  pyruvate. 
E)  most amino acids. 
A)  glycerol. 
B)  lactate. 
C)  acetate. 
D)  pyruvate. 
E)  most amino acids.

Question 14

If NADPH is needed for biosynthetic reactions but ribose-5-P is not needed, which of the following best represents the net reaction of the pentose phosphate pathway?

Accepted Answer

A)  4 Fruc-6-P + 2 glyceraldehyde-3-P → 6 ribose-5-P 
B)  3 Gluc-6-P + 6 NADP+ → 6 NADPH + 3 CO2 + 2 Fruc-6-P + 1 glyceraldehyde-3-P 
C)  Gluc-6-P + 2 NADP+ → 2 NADPH + CO2 + ribose-5-P 
D)  both b and c will occur 
E)  None of the above 
A)  4 Fruc-6-P + 2 glyceraldehyde-3-P → 6 ribose-5-P 
B)  3 Gluc-6-P + 6 NADP+ → 6 NADPH + 3 CO2 + 2 Fruc-6-P + 1 glyceraldehyde-3-P 
C)  Gluc-6-P + 2 NADP+ → 2 NADPH + CO2 + ribose-5-P 
D)  both b and c will occur 
E)  None of the above

Question 15

A blood test for "Glycated hemoglobin" can determine the:

Accepted Answer

A)  present blood glucose concentration. 
B)  average glucose concentration in the blood over the past several months. 
C)  level of AGEs in the blood stream. 
D)  blood glucose concentration over this last month. 
E)  none are true. 
A)  present blood glucose concentration. 
B)  average glucose concentration in the blood over the past several months. 
C)  level of AGEs in the blood stream. 
D)  blood glucose concentration over this last month. 
E)  none are true.

Question 16

Pyruvate carboxylase consumes a(n) ____ to drive a carboxylation so that ____ could use the energy from decarboxylation to facilitate formation of PEP.

Accepted Answer

A)  NADH; pyruvate dehydrogenase 
B)  NADH; lactate dehydrogenase 
C)  ATP; pyruvate kinase 
D)  ATP; PEP carboxykinase 
E)  GTP; nucleotide diphosphate kinase 
A)  NADH; pyruvate dehydrogenase 
B)  NADH; lactate dehydrogenase 
C)  ATP; pyruvate kinase 
D)  ATP; PEP carboxykinase 
E)  GTP; nucleotide diphosphate kinase

Question 17

In the pyruvate carboxylase catalyzed reaction, bicarbonate is "activated" by attachment to the ____ of ATP to form ____.

Accepted Answer

A)  β-phosphate; carbonyl ADP 
B)  α-phosphate; carbonyl AMP 
C)  α-phosphate; carbonylphosphate 
D)  γ-phosphate; carbonylphosphate 
E)  γ-phosphate; carbonyl AMP 
A)  β-phosphate; carbonyl ADP 
B)  α-phosphate; carbonyl AMP 
C)  α-phosphate; carbonylphosphate 
D)  γ-phosphate; carbonylphosphate 
E)  γ-phosphate; carbonyl AMP

Question 18

AMP is often used in the cytosol as an indicator of low cellular energy. Which of the following enzymes would be inhibited by AMP?

Accepted Answer

A)  glucose-6-phosphate dehydrogenase 
B)  phosphofructokinase-1 
C)  glycogen synthase 
D)  glyceraldehyde-3-phosphate dehydrogenase 
E)  none of the above 
A)  glucose-6-phosphate dehydrogenase 
B)  phosphofructokinase-1 
C)  glycogen synthase 
D)  glyceraldehyde-3-phosphate dehydrogenase 
E)  none of the above

Question 19

Among the many physiological changes elicited by epinephrine, the initiation of the adenylyl cyclase cascade includes all EXCEPT:

Accepted Answer

A)  activation of glycogenolysis in liver. 
B)  inhibition of glycogen synthase. 
C)  stimulation of glycolysis by 2000 fold. 
D)  activation of glycogenolysis in muscles. 
E)  all are true 
A)  activation of glycogenolysis in liver. 
B)  inhibition of glycogen synthase. 
C)  stimulation of glycolysis by 2000 fold. 
D)  activation of glycogenolysis in muscles. 
E)  all are true

Question 20

Glucose-6-phosphatase is located in the ____ and produces ____ in vesicles that diffuse to the ____ releasing their contents into the blood stream.

Accepted Answer

A)  mitochondria; lactate; cytosol 
B)  cytosol; glucose; plasma membrane 
C)  endoplasmic reticulum; glucose-6-phosphate; cytosol 
D)  endoplasmic reticulum; glucose; plasma membrane 
E)  cytosol; glucose-6-phosphate; endoplasmic reticulum 
A)  mitochondria; lactate; cytosol 
B)  cytosol; glucose; plasma membrane 
C)  endoplasmic reticulum; glucose-6-phosphate; cytosol 
D)  endoplasmic reticulum; glucose; plasma membrane 
E)  cytosol; glucose-6-phosphate; endoplasmic reticulum

Exam 22: Gluconeogenesis, Glycogen Metabolism, and the Pentose Phosphate Pathway

All are true for α-amylase EXCEPT:

Glucose monitoring devices use the reaction, Glucose + O2 + H2O → gluconate + 2 ____, which is catalyzed by the enzyme ____.

When a cell with the pentose phosphate pathway has need for more pentose phosphates, but no additional NADPH:

If both NADPH and ribose-5-P are needed which of the following best represents the net reaction of the pentose phosphate pathway?

In the gluconeogenic pathway, the three regulated reactions of glycolysis catalyzed by ____, ____ and ____ are replaced by alternative reactions.

Which of the following can be used as a substrate for gluconeogenesis in the liver?

The polyol pathway is a suspected pathway for diabetic induced cataract formation and involves the enzyme:

Characteristics of glucose-6-phosphate dehydrogenase include all EXCEPT:

An individual with von Gierke's disease lacks the enzyme ____ which is a liver enzyme used to maintain ____. As a result, the patient is ____.

Which of the following occurs as a result of cortisol release from the adrenal gland?

All are substrates for gluconeogenesis EXCEPT:

If NADPH is needed for biosynthetic reactions but ribose-5-P is not needed, which of the following best represents the net reaction of the pentose phosphate pathway?

A blood test for "Glycated hemoglobin" can determine the:

Pyruvate carboxylase consumes a(n) ____ to drive a carboxylation so that ____ could use the energy from decarboxylation to facilitate formation of PEP.

In the pyruvate carboxylase catalyzed reaction, bicarbonate is "activated" by attachment to the ____ of ATP to form ____.

AMP is often used in the cytosol as an indicator of low cellular energy. Which of the following enzymes would be inhibited by AMP?

Among the many physiological changes elicited by epinephrine, the initiation of the adenylyl cyclase cascade includes all EXCEPT:

Glucose-6-phosphatase is located in the ____ and produces ____ in vesicles that diffuse to the ____ releasing their contents into the blood stream.

The Facts of Life: Chemistry Is the Logic of Biological Phenomena

Water: the Medium of Life

Thermodynamics of Biological Systems

Amino Acids and the Peptide Bond

Proteins: Their Primary Structure and Biological Functions

Proteins: Secondary, Tertiary, and Quaternary Structure

Carbohydrates and the Glycoconjugates of Cell Surfaces

Lipids

Membranes and Membrane Transport

Nucleotides and Nucleic Acids

Structure of Nucleic Acids

Recombinant Dna, Cloning, Chimeric Genes, and Synthetic Biology

Enzymeskinetics and Specificity

Mechanisms of Enzyme Action

Enzyme Regulation

Molecular Motors

Metabolism: an Overview

Glycolysis

The Tricarboxylic Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Fatty Acid Catabolism

Lipid Biosynthesis

Nitrogen Acquisition and Amino Acid Metabolism

Synthesis and Degradation of Nucleotides

Metabolic Integration and Organ Specialization

Dna Metabolism: Replication, Recombination, and Repair

Transcription and the Regulation of Gene Expression

Protein Synthesis

Completing the Protein Life Cycle: Folding, Processing, and Degradation

The Reception and Transmission of Extracellular Information

Filters

Glucose monitoring devices use the reaction, Glucose + O₂ + H₂O → gluconate + 2 , which is catalyzed by the enzyme .

In the gluconeogenic pathway, the three regulated reactions of glycolysis catalyzed by , and are replaced by alternative reactions.

An individual with von Gierke's disease lacks the enzyme which is a liver enzyme used to maintain . As a result, the patient is .

Pyruvate carboxylase consumes a(n) to drive a carboxylation so that could use the energy from decarboxylation to facilitate formation of PEP.

In the pyruvate carboxylase catalyzed reaction, bicarbonate is "activated" by attachment to the of ATP to form .

Glucose-6-phosphatase is located in the and produces in vesicles that diffuse to the releasing their contents into the blood stream.