Question 1

Glycolytic enzymes are known to function in each of the following processes except

Accepted Answer

Glycolytic enzymes are involved in various cellular processes including transcriptional regulation, gluconeogenesis, apoptosis regulation, and coordinating glycolysis with mitochondrial respiration. However, they are not directly involved in the reduction of oxygen to form water, which is a function of the electron transport chain in mitochondria.

Question 2

Although pyruvate is the end product of glycolysis and no more ATP is generated by fermentation of pyruvate to ethanol,yeast produce ethanol under anaerobic conditions because

Accepted Answer

The correct answer is C because the fermentation of pyruvate to ethanol allows for the regeneration of NAD+, which is essential for glycolysis to continue. This process ensures that NADH is oxidized back to NAD+, maintaining the necessary balance for glycolysis to proceed under anaerobic conditions.

Question 3

A temporary oxygen deficit during strenuous exercise causes a muscle to

Accepted Answer

During strenuous exercise, when oxygen supply is insufficient for aerobic respiration, muscles switch to anaerobic metabolism, fermenting pyruvate to lactate to continue producing ATP, albeit less efficiently than with oxygen.

Question 4

Glycolytic enzymes have been found to have roles in all of the following except

Accepted Answer

Glycolytic enzymes are primarily involved in the breakdown of glucose to provide energy for the cell. While they have been found to play roles in transcriptional repression, apoptosis inhibition, acting as transcriptional activators, and stimulating cell migration, there is no evidence to suggest they are directly involved in GTP hydrolysis. GTP hydrolysis is more commonly associated with proteins involved in signal transduction and cellular processes like protein synthesis, not with glycolytic enzymes.

Question 5

Pyruvate can be a substrate or product involved in each of the following except

Accepted Answer

Pyruvate is a key intermediate in several metabolic pathways. It can be produced from glucose through glycolysis (aerobic or anaerobic), be used to synthesize glucose in gluconeogenesis, be converted into lactate or ethanol in fermentation, and serve as a precursor for the synthesis of amino acids. Therefore, it can be involved in all the processes listed.

Question 6

Allosteric regulation of key enzymes in glycolytic and gluconeogenesis pathways may involve each of the following except

Accepted Answer

The answer of Allosteric regulation of key enzymes in glycolytic...

Question 7

Which glycolytic enzyme uses ATP to phosphorylate glucose?

Accepted Answer

Hexokinase is the enzyme responsible for phosphorylating glucose using ATP, which is the first step in the glycolysis pathway.

Question 8

The phosphate group that is removed from PEP when it becomes pyruvate

Accepted Answer

The phosphate group removed from phosphoenolpyruvate (PEP) during its conversion to pyruvate is transferred to ADP to synthesize ATP, a process catalyzed by the enzyme pyruvate kinase. This is a key step in glycolysis, where energy is conserved in the form of ATP.

Question 9

During the conversion of 1,3-bisphosphoglycerate to 3-phosphoglycerate and phosphoenolpyruvate,a phosphate group is added to ATP to generate ATP.The mechanism for ATP production in this reaction is

Accepted Answer

The conversion of 1,3-bisphosphoglycerate to 3-phosphoglycerate and the conversion of phosphoenolpyruvate to pyruvate involve substrate-level phosphorylation, where a phosphate group is directly transferred from a substrate to ADP to form ATP, without the need for an electron transport chain or a proton gradient.

Question 10

Fermentation directly

Accepted Answer

Fermentation regenerates NAD⁺ from NADH, allowing glycolysis to continue in the absence of oxygen.

Question 11

Positron emission tomography (PET)of a patient who has consumed the radiotracer fluorodeoxyglucose reveals tumors because

Accepted Answer

Cancer cells have a higher rate of glucose metabolism compared to normal cells due to their rapid growth and proliferation. Fluorodeoxyglucose (FDG) is a glucose analog that gets taken up by cells but cannot be metabolized further than the initial phosphorylation step. This results in its accumulation within cells that have high glucose uptake, such as cancer cells, making them visible on PET scans.

Question 12

In animal cells,glycolysis and gluconeogenesis are regulated to ensure that both processes are reciprocally active.This regulation involves each of the following compounds except

Accepted Answer

NADH is not directly involved in the reciprocal regulation of glycolysis and gluconeogenesis. The other compounds listed play roles in regulating these pathways.

Question 13

Cells can store energy in each of the following molecules except

Accepted Answer

Cells can store energy in all of the molecules listed: ATP (adenosine triphosphate), GTP (guanosine triphosphate), creatine phosphate, and NADH (nicotinamide adenine dinucleotide) are all involved in energy storage and transfer in various cellular processes.

Question 14

Each of the following can be the final electron acceptor in bacterial aerobic or anaerobic respiration except

Accepted Answer

Pyruvate serves as an electron donor in fermentation processes, not as a final electron acceptor in aerobic or anaerobic respiration. Oxygen is the final electron acceptor in aerobic respiration, while compounds like sulfur, hydrogen ions, and various metals can serve as final electron acceptors in anaerobic respiration.

Question 15

Each of the following is a substrate for glycolysis except

Accepted Answer

The answer of Each of the following is a substrate...

Question 16

Which of the following is not a product of fermentation?

Accepted Answer

Glycogen is not a product of fermentation. Fermentation typically produces substances like lactate, ethanol, and gases, depending on the organism and conditions, but glycogen is a form of stored glucose in organisms, not a fermentation product.

Question 17

Glucose transported into human cells can be transformed into all of the following except

Accepted Answer

Glucose is a versatile molecule that can be converted into various substances within the human body, including carbon dioxide and water through aerobic respiration (B), lactate in anaerobic conditions (C), glycogen for storage (D), and acetyl CoA for fat synthesis (E). However, it is not directly converted into sucrose for energy production within human cells. Sucrose is a disaccharide made of glucose and fructose, primarily found in plants for energy storage.

Question 18

The process of gluconeogenesis converts pyruvate or lactate into

Accepted Answer

Gluconeogenesis is a metabolic pathway that results in the generation of glucose from certain non-carbohydrate carbon substrates such as pyruvate, lactate, glycerol, and glucogenic amino acids.

Question 19

In the first step of glycolysis,glucose can be phosphorylated to glucose-6-phosphate,because

Accepted Answer

The phosphorylation of glucose to glucose-6-phosphate is driven by the energy released from breaking a phosphoanhydride bond in ATP, which has a higher energy of hydrolysis than is required for the formation of the phosphoester bond in glucose-6-phosphate. This makes the reaction energetically favorable.

Question 20

Each of the following is fermentation products except

Accepted Answer

Acetyl CoA is not a product of fermentation; it is an intermediate in various metabolic pathways, including the citric acid cycle and fatty acid synthesis, rather than an end product of fermentation. Fermentation typically results in the production of substances like ethanol, lactate, propionate, and butyrate, depending on the organism and conditions.

Quiz 9: Chemotrophic Energy Metabolism: Glycolysis and Fermentation