Question 1

Which citrate cycle metabolite is used as a precursor for heme biosynthesis?

Accepted Answer

A)  succinyl Co-A 
B)  oxaloacetate 
C)    -ketoglutarate 
D)  malate 
A)  succinyl Co-A 
B)  oxaloacetate 
C)    -ketoglutarate 
D)  malate A

Question 2

Which of the following is the cause of the irreversible blockage of the catalytic activity of lipoamide-containing enzymes?

Accepted Answer

A)  cheilosis 
B)  pellagra 
C)  beriberi 
D)  arsenic poisoning 
A)  cheilosis 
B)  pellagra 
C)  beriberi 
D)  arsenic poisoning D

Question 3

Pantothenic acid is essential for life because it is the vitamin precursor to the molecule that

Accepted Answer

A)  provides a reactive disulfide that can participate in redox reactions within the enzyme active site of pyruvate dehydrogenase. 
B)  can accept one or two electrons in redox reactions in the cell. 
C)  is involved in at least 200 redox reactions in the cell. 
D)  is a cofactor in the biosynthetic pathways that produce fatty acids, acetylcholine, heme, and cholesterol. 
A)  provides a reactive disulfide that can participate in redox reactions within the enzyme active site of pyruvate dehydrogenase. 
B)  can accept one or two electrons in redox reactions in the cell. 
C)  is involved in at least 200 redox reactions in the cell. 
D)  is a cofactor in the biosynthetic pathways that produce fatty acids, acetylcholine, heme, and cholesterol. D

Question 4

What two features of the citrate cycle make it unique compared with linear metabolic pathways?

Accepted Answer

Oxaloacetate is both the substrate for t

Question 5

If acetyl-CoA is not metabolized by the citrate cycle,the molecule in the cell

Accepted Answer

A)  undergoes fatty acid metabolism. 
B)  is transported across the cell membrane. 
C)  is used to synthesize amino acids. 
D)  is used during glycolysis. 
A)  undergoes fatty acid metabolism. 
B)  is transported across the cell membrane. 
C)  is used to synthesize amino acids. 
D)  is used during glycolysis.

Question 6

In two turns of the citrate cycle,how many electrons are transferred from the citrate cycle intermediates to NAD+ and FAD?

Accepted Answer

A)  4 
B)  8 
C)  12 
D)  16 
A)  4 
B)  8 
C)  12 
D)  16

Question 7

Identify the E2 subunit in the reaction schematic of the pyruvate dehydrogenase reaction below.

Accepted Answer

A)  pyruvate dehydrogenase 
B)  dihydrolipoyl dehydrogenase 
C)  dihydrolipopyl acetyltransferase 
D)  flavin adenine dinucleotide 
A)  pyruvate dehydrogenase 
B)  dihydrolipoyl dehydrogenase 
C)  dihydrolipopyl acetyltransferase 
D)  flavin adenine dinucleotide

Question 8

Thiamine pyrophosphate functions as a coenzyme in which reactions in the citrate cycle?

Accepted Answer

A)  pyruvate dehydrogenase and succinate dehydrogenase 
B)  pyruvate dehydrogenase and  -ketoglutarate dehydrogenase 
C)  malate dehydrogenase and succinate dehydrogenase 
D)  malate dehydrogenase and  -ketoglutarate dehydrogenase 
A)  pyruvate dehydrogenase and succinate dehydrogenase 
B)  pyruvate dehydrogenase and  -ketoglutarate dehydrogenase 
C)  malate dehydrogenase and succinate dehydrogenase 
D)  malate dehydrogenase and  -ketoglutarate dehydrogenase

Question 9

Which anaplerotic reaction balances the input of oxaloacetate with acetyl-CoA in the citrate cycle by converting pyruvate into oxaloacetate?

Accepted Answer

A)  pyruvate carboxylase 
B)  malate dehydrogenase 
C)  malic enzyme 
D)  pyruvate kinase 
A)  pyruvate carboxylase 
B)  malate dehydrogenase 
C)  malic enzyme 
D)  pyruvate kinase

Question 10

Explain how arsenic affects the pyruvate dehydrogenase reaction.

Accepted Answer

Arsenite covalently modifies lipoamide c

Question 11

What is the fate of oxaloacetate when it is not used in the citrate cycle?

Accepted Answer

A)  cholesterol synthesis 
B)  heme synthesis 
C)  amino acid synthesis 
D)  gluconeogenesis 
A)  cholesterol synthesis 
B)  heme synthesis 
C)  amino acid synthesis 
D)  gluconeogenesis

Question 12

You have a patient who has been traveling through India and Bangladesh who is presenting with ulcerous skin lesions.What could cause this issue and what is your recommendation?

Accepted Answer

The symptom plus the travel locales are

Question 13

Using the table below,calculate   
and determine if the conversion from malate to oxaloacetate is favorable under standard biochemical conditions.
Malate + NAD+ $\to$ Oxaloacetate + H+ + NADH

Accepted Answer

Calculate the @#IMG-DLM&_TB6697_11 for the coupled

Question 14

In the following figure,identify and explain the specific pathways (A-F)that are shared with the citrate cycle intermediates.

Accepted Answer

A.Succinyl-CoA and glycine synthesize @#IMG-DLM&_T

Question 15

The citrate cycle is considered to be a(n)__________ pathway.

Accepted Answer

A)  anabolic 
B)  catabolic 
C)  anaplerotic 
D)  amphibolic 
A)  anabolic 
B)  catabolic 
C)  anaplerotic 
D)  amphibolic

Question 16

Which of the following is a product of the net reaction of the citrate cycle?

Accepted Answer

A)  FAD 
B)  H2O 
C)  H+ 
D)  NAD+ 
A)  FAD 
B)  H2O 
C)  H+ 
D)  NAD+

Question 17

Outline the five reaction steps of the conversion from pyruvate to acetyl-CoA.

Accepted Answer

Step 1: Pyruvate dehydrogenase catalyzes

Question 18

Where do citrate cycle reactions in eukaryotic cells take place?

Accepted Answer

A)  cytosol 
B)  mitochondrial matrix 
C)  endoplasmic reticulum 
D)  nucleus 
A)  cytosol 
B)  mitochondrial matrix 
C)  endoplasmic reticulum 
D)  nucleus

Question 19

Coenzyme A is derived from which of the following vitamins?

Accepted Answer

A)  thiamine 
B)  pantothenic acid 
C)  riboflavin 
D)  niacin 
A)  thiamine 
B)  pantothenic acid 
C)  riboflavin 
D)  niacin

Question 20

According to the   ,which of the following exergonic reactions is most likely irreversible under normal cellular conditions and is considered to be the rate-limiting step of the citrate cycle?

Accepted Answer

A)  citrate synthase 
B)  fumarase 
C)  isocitrate dehydrogenase 
D)    -ketoglutarate dehydrogenase 
A)  citrate synthase 
B)  fumarase 
C)  isocitrate dehydrogenase 
D)    -ketoglutarate dehydrogenase

Exam 10: The Citrate Cycle

Which citrate cycle metabolite is used as a precursor for heme biosynthesis?

Which of the following is the cause of the irreversible blockage of the catalytic activity of lipoamide-containing enzymes?

Pantothenic acid is essential for life because it is the vitamin precursor to the molecule that

What two features of the citrate cycle make it unique compared with linear metabolic pathways?

If acetyl-CoA is not metabolized by the citrate cycle,the molecule in the cell

In two turns of the citrate cycle,how many electrons are transferred from the citrate cycle intermediates to NAD+ and FAD?

Identify the E2 subunit in the reaction schematic of the pyruvate dehydrogenase reaction below.

Thiamine pyrophosphate functions as a coenzyme in which reactions in the citrate cycle?

Which anaplerotic reaction balances the input of oxaloacetate with acetyl-CoA in the citrate cycle by converting pyruvate into oxaloacetate?

Explain how arsenic affects the pyruvate dehydrogenase reaction.

What is the fate of oxaloacetate when it is not used in the citrate cycle?

You have a patient who has been traveling through India and Bangladesh who is presenting with ulcerous skin lesions.What could cause this issue and what is your recommendation?

Using the table below,calculate and determine if the conversion from malate to oxaloacetate is favorable under standard biochemical conditions. Malate + NAD+ →\to→ Oxaloacetate + H+ + NADH

In the following figure,identify and explain the specific pathways (A-F)that are shared with the citrate cycle intermediates.

The citrate cycle is considered to be a(n)__________ pathway.

Which of the following is a product of the net reaction of the citrate cycle?

Outline the five reaction steps of the conversion from pyruvate to acetyl-CoA.

Where do citrate cycle reactions in eukaryotic cells take place?

Coenzyme A is derived from which of the following vitamins?

According to the ,which of the following exergonic reactions is most likely irreversible under normal cellular conditions and is considered to be the rate-limiting step of the citrate cycle?

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

Glycolysis: a Paradigm of Metabolic Regulation

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

In two turns of the citrate cycle,how many electrons are transferred from the citrate cycle intermediates to NAD⁺ and FAD?