Question 1

Describe how the glycolytic pathway provides aerobic energy to the citrate cycle and oxidative phosphorylation.

Accepted Answer

The glycolytic pathway generates ATP and pyruvate, which are required for the other pathways.

Question 2

Name the following disaccharide using descriptive nomenclature.

Accepted Answer

A)  Glc($\alpha$1$\rightarrow$$\beta$2)Fru 
B)  Glc($\alpha$1$\rightarrow$$\alpha$2)Glc 
C)  Gal($\beta$1$\rightarrow$4)Glc 
D)  Glc($\alpha$1$\rightarrow$$\alpha$4)Glc 
A)  Glc($\alpha$1$\rightarrow$$\beta$2)Fru 
B)  Glc($\alpha$1$\rightarrow$$\alpha$2)Glc 
C)  Gal($\beta$1$\rightarrow$4)Glc 
D)  Glc($\alpha$1$\rightarrow$$\alpha$4)Glc C

Question 3

Explain why people who have the genetic disease lactate dehydrogenase deficiency cannot maintain intense exercise.

Accepted Answer

These people cannot maintain sustained periods of intense exercise because of an
inability to use glycolysis to produce ATP needed for muscle concentration under anaerobic conditions. If the lactate dehydrogenase reaction is not fully functional, NADH oxidation to regenerate NAD⁺does not occur at a rate high enough to sustain glycolysis. This causes the muscle cells to run out of ATP quickly, leading to fatigue and even muscle damage.

Question 4

What effect do elevated levels of ATP have on glycolysis?

Accepted Answer

A)  decrease the affinity of PFK-1 for fructose-6-P and slow rate of the pathway 
B)  increase the affinity of PFK-1 for fructose-6-P and increase the rate of the pathway 
C)  increase the concentration of PFK-1 in the R-state 
D)  increase the concentration of glucose entering glycolysis 
A)  decrease the affinity of PFK-1 for fructose-6-P and slow rate of the pathway 
B)  increase the affinity of PFK-1 for fructose-6-P and increase the rate of the pathway 
C)  increase the concentration of PFK-1 in the R-state 
D)  increase the concentration of glucose entering glycolysis

Question 5

NAD+ is required for the oxidative step of glycolysis. Briefly discuss how NAD+ is regenerated from NADH under aerobic and anaerobic conditions.

Accepted Answer

Under aerobic conditions, electrons pass

Question 6

What is the potential metabolic fate of pyruvate during strenuous exercise?

Accepted Answer

A)  produce lactate 
B)  produce ethanol 
C)  produce carbon dioxide and water 
D)  produce glucose 
A)  produce lactate 
B)  produce ethanol 
C)  produce carbon dioxide and water 
D)  produce glucose

Question 7

Why do individuals with defects in glycolytic enzymes have altered oxygen transport capabilities?

Accepted Answer

It is due to increased or decreased leve

Question 8

Glucose and fructose are both C6H1 2O6. What is the structural difference between them?

Accepted Answer

A)  Glucose is a five-membered ring and fructose is a six-membered ring. 
B)  Fructose is a five-membered ring and glucose is a six-membered ring. 
C)  Glucose is a linear molecule and fructose is a ring. 
D)  Glucose is found in the boat conformation and fructose is a chair conformation. 
A)  Glucose is a five-membered ring and fructose is a six-membered ring. 
B)  Fructose is a five-membered ring and glucose is a six-membered ring. 
C)  Glucose is a linear molecule and fructose is a ring. 
D)  Glucose is found in the boat conformation and fructose is a chair conformation.

Question 9

A carbohydrate that reacts with oxidizing agents such as Cu+2 is called a(n) sugar.

Accepted Answer

A)  oxidizing 
B)  reducing 
C)  rentose 
D)  aldose 
A)  oxidizing 
B)  reducing 
C)  rentose 
D)  aldose

Question 10

The rate limiting step can be defined as a level of enzyme activity that can be regulated to be __________ even when substrate levels are _.

Accepted Answer

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

Question 11

Which of the following is the correct net reaction for glycolysis?

Accepted Answer

A)  glucose + 2 ATP $\rightarrow$ 2 lactate + 2 ADP + 2 Pi 
B)  glucose + 2 ADP + 2 Pi + 2 NAD+ $\rightarrow$2 pyruvate + 2 ATP + 2 NADH + 4 H+ 
C)  glucose + 2 ADP + 2 Pi $\rightarrow$ 2 CH3CH2OH + 2 CO2 + 2 ATP 
D)  glucose + 2 ADP + 2 Pi + 2 NAD+ $\rightarrow$ 2 pyruvate + 2 ATP + 2 NADH + 2 H+ + 2H2O 
A)  glucose + 2 ATP $\rightarrow$ 2 lactate + 2 ADP + 2 Pi 
B)  glucose + 2 ADP + 2 Pi + 2 NAD+ $\rightarrow$2 pyruvate + 2 ATP + 2 NADH + 4 H+ 
C)  glucose + 2 ADP + 2 Pi $\rightarrow$ 2 CH3CH2OH + 2 CO2 + 2 ATP 
D)  glucose + 2 ADP + 2 Pi + 2 NAD+ $\rightarrow$ 2 pyruvate + 2 ATP + 2 NADH + 2 H+ + 2H2O

Question 12

Which reaction in glycolysis is a redox reaction?

Accepted Answer

A)  glyceraldehyde-3-P $\rightarrow$1,3-bisphosphoglycerate 
B)  glucose $\rightarrow$ glucose-6-P 
C)  2-phosphoglycerate $\rightarrow$ phosphoenolpyruvate 
D)  fructose-6-P $\rightarrow$ fructose-1,6-BP 
A)  glyceraldehyde-3-P $\rightarrow$1,3-bisphosphoglycerate 
B)  glucose $\rightarrow$ glucose-6-P 
C)  2-phosphoglycerate $\rightarrow$ phosphoenolpyruvate 
D)  fructose-6-P $\rightarrow$ fructose-1,6-BP

Question 13

Anomers differ from each other by changes at the carbon.

Accepted Answer

A)  chiral 
B)  C-2 
C)  C-3 
D)  C-1 
A)  chiral 
B)  C-2 
C)  C-3 
D)  C-1

Question 14

Which of the following compounds contains a "high-energy" bond and is used to produce ATP by substrate-level phosphorylation in glycolysis?

Accepted Answer

A)  glucose 
B)  fructose-1,6-BP 
C)  3-phosphoglycerate 
D)  1,3-bisphosphoglycerate 
A)  glucose 
B)  fructose-1,6-BP 
C)  3-phosphoglycerate 
D)  1,3-bisphosphoglycerate

Question 15

Where in the body is glucokinase found?

Accepted Answer

A)  small intestine 
B)  liver 
C)  heart 
D)  thyroid 
A)  small intestine 
B)  liver 
C)  heart 
D)  thyroid

Question 16

Compare the structure of an aldose to a ketose.

Accepted Answer

A)  Ketose has a carbon backbone with an aldehyde group at the end of the molecule, whereas aldose has a ketone group at the end of the molecule. 
B)  Ketose has a carbon backbone with a ketone group at the end of the molecule, whereas aldose has an aldehyde group at the end of the molecule. 
C)  Both have a carbon backbone where ketose has a ketone group at the end of the molecule, and aldose also has an aldehyde group at the end of the molecule. 
D)  Both have a carbon backbone where ketose has a ketone group on the second carbon in the molecule, and aldose also has an aldehyde group at the end of the molecule. 
A)  Ketose has a carbon backbone with an aldehyde group at the end of the molecule, whereas aldose has a ketone group at the end of the molecule. 
B)  Ketose has a carbon backbone with a ketone group at the end of the molecule, whereas aldose has an aldehyde group at the end of the molecule. 
C)  Both have a carbon backbone where ketose has a ketone group at the end of the molecule, and aldose also has an aldehyde group at the end of the molecule. 
D)  Both have a carbon backbone where ketose has a ketone group on the second carbon in the molecule, and aldose also has an aldehyde group at the end of the molecule.

Question 17

A chiral center is an atom with

Accepted Answer

A)  two different functional groups and a strong dipole. 
B)  four different functional groups and which lacks a plane of symmetry. 
C)  all the same functional groups and a plane of symmetry. 
D)  the ability to hydrogen bond. 
A)  two different functional groups and a strong dipole. 
B)  four different functional groups and which lacks a plane of symmetry. 
C)  all the same functional groups and a plane of symmetry. 
D)  the ability to hydrogen bond.

Question 18

Is the net reaction favorable for the following series of coupled reactions?

Accepted Answer

A)  Yes, $\Delta$G $\degree$'  '  '  > 0 
D)  No, $\Delta$G $\degree$'  > 0 
A)  Yes, $\Delta$G $\degree$'  '  '  > 0 
D)  No, $\Delta$G $\degree$'  > 0

Question 19

Which of the following metabolic pathways is only found in plants?

Accepted Answer

A)  glycolysis 
B)  citrate cycle 
C)  photosynthesis 
D)  urea cycle 
A)  glycolysis 
B)  citrate cycle 
C)  photosynthesis 
D)  urea cycle

Question 20

Catabolic pathways are always paired with anabolic pathways. Why?

Accepted Answer

A)  Catabolic pathways build up new molecules and anabolic break down molecules. 
B)  Catabolic pathways break down molecules and anabolic build up new molecules. 
C)  Both require ATP to operate. 
D)  Both require redox reactions to operate. 
A)  Catabolic pathways build up new molecules and anabolic break down molecules. 
B)  Catabolic pathways break down molecules and anabolic build up new molecules. 
C)  Both require ATP to operate. 
D)  Both require redox reactions to operate.

Exam 9: Glycolysis: a Paradigm of Metabolic Regulation

Describe how the glycolytic pathway provides aerobic energy to the citrate cycle and oxidative phosphorylation.

Name the following disaccharide using descriptive nomenclature.

Explain why people who have the genetic disease lactate dehydrogenase deficiency cannot maintain intense exercise.

What effect do elevated levels of ATP have on glycolysis?

NAD+ is required for the oxidative step of glycolysis. Briefly discuss how NAD+ is regenerated from NADH under aerobic and anaerobic conditions.

What is the potential metabolic fate of pyruvate during strenuous exercise?

Why do individuals with defects in glycolytic enzymes have altered oxygen transport capabilities?

Glucose and fructose are both C6H1 2O6. What is the structural difference between them?

A carbohydrate that reacts with oxidizing agents such as Cu+2 is called a(n) sugar.

The rate limiting step can be defined as a level of enzyme activity that can be regulated to be __________ even when substrate levels are _.

Which of the following is the correct net reaction for glycolysis?

Which reaction in glycolysis is a redox reaction?

Anomers differ from each other by changes at the carbon.

Which of the following compounds contains a "high-energy" bond and is used to produce ATP by substrate-level phosphorylation in glycolysis?

Where in the body is glucokinase found?

Compare the structure of an aldose to a ketose.

A chiral center is an atom with

Is the net reaction favorable for the following series of coupled reactions?

Which of the following metabolic pathways is only found in plants?

Catabolic pathways are always paired with anabolic pathways. Why?

Principles of Biochemistry

Physical Biochemistry: Energy Conversion, Water, and Membranes

Nucleic Acid Structure and Function

Protein Structure

Methods in Protein Biochemistry

Protein Function

Enzyme Mechanisms

Cell Signaling Systems

The Citrate Cycle

Oxidative Phosphorylation

Photosynthesis

Carbohydrate Structure and Function

Carbohydrate Metabolism

Lipid Structure and Function

Lipid Metabolism

Amino Acid Metabolism

Nucleotide Metabolism

Metabolic Integration

DNA Replication, Repair, and Recombination

RNA Synthesis, Processing, and Gene Silencing

Protein Synthesis, Posttranslational Modification, and Transport

Gene Regulation

Filters

NAD⁺is required for the oxidative step of glycolysis. Briefly discuss how NAD⁺is regenerated from NADH under aerobic and anaerobic conditions.

Glucose and fructose are both C₆H₁ ₂O₆. What is the structural difference between them?