Question 1

Foods are broken down into simple molecular subunits for distribution and use throughout the body.Which type of simple subunits, listed below, is used preferentially as an energy source?

Accepted Answer

Simple sugars, such as glucose, are the preferred energy source for cells in the body. They can be easily broken down and used for energy through processes like cellular respiration. While proteins and free fatty acids can also be broken down for energy, they are typically used as structural components or stored for later use, respectively. Glycerol is a component of fats, but it cannot be used as a standalone energy source and must first be converted into glucose or free fatty acids.

Question 2

On a diet consisting of nothing but protein, which of the following is the most likely outcome?

Accepted Answer

A diet consisting exclusively of protein will result in excess nitrogen intake, which the body cannot store. Therefore, more nitrogenous waste will be excreted, leading to potential complications for the kidneys. This is why it is important to have a balanced diet that includes carbohydrates and fats in addition to protein.

Question 3

Glycolysis generates more stored energy than it expends.What is the net number of activated carrier molecules produced in this process (number and type of molecules produced minus the number of those molecules used as input)?

Accepted Answer

Glycolysis results in a net gain of 2 ATP and 2 NADH molecules. This accounts for the energy produced minus the energy expended during the process.

Question 4

The advantage to the cell of the gradual oxidation of glucose during cellular respiration compared with its combustion to CO₂ and H₂O in a single step is that

Accepted Answer

The gradual oxidation of glucose during cellular respiration allows for the extraction of energy in usable amounts, allowing the cell to use the energy to perform its functions. Combusting glucose to CO₂ and H₂O in a single step would likely result in the loss of energy as heat and the production of more CO₂, but this would not necessarily be useful to the cell. Therefore, the advantage to the cell is that it can extract a usable form of energy through gradual oxidation.

Question 5

Which of the following descriptions best matches the function of a kinase?

Accepted Answer

A kinase is an enzyme that catalyzes the addition of phosphate groups to other molecules, typically transferring a phosphate group from ATP to a target molecule. This process is known as phosphorylation and can activate or deactivate a molecule, altering its function in the cell.

Question 6

Which of the following steps or processes in aerobic respiration include the production of carbon dioxide?

Accepted Answer

The conversion of pyruvate to acetyl CoA (a step in the link reaction between glycolysis and the Krebs cycle) involves the decarboxylation of pyruvate, which results in the production of carbon dioxide.

Question 7

Which reaction does the enzyme phosphoglucose isomerase catalyze?

Accepted Answer

The enzyme phosphoglucose isomerase catalyzes the conversion of glucose 6-phosphate to fructose 6-phosphate in the second step of glycolysis.

Question 8

The conversion of glyceraldehyde 3-phosphate to 1,3 bisphosphoglycerate in step 6 of glycolysis generates a "high-energy" phosphoanhydride bond.Which of the following BEST describes what happens to that bond in step 7?

Accepted Answer

The high-energy phosphoanhydride bond in 1,3 bisphosphoglycerate is used to drive the formation of ATP in step 7 of glycolysis. This process is known as substrate-level phosphorylation. The phosphate from 1,3 bisphosphoglycerate is transferred to ADP, forming ATP and yielding 3-phosphoglycerate.

Question 9

Select the best option to fill in the blanks of the following statement: Fermentation is a/an __________ process that converts __________into carbon dioxide and __________.

Accepted Answer

Fermentation is commonly an anaerobic process that converts pyruvate into either lactate or ethanol, as well as carbon dioxide. Option A is the only one that aligns with the commonly understood definition of fermentation. Option B is almost correct, but lactate is produced in humans during anaerobic respiration, not fermentation. Option C is incorrect because fermentation can occur in both prokaryotic and eukaryotic cells, not just eukaryotic cells. Option D is incorrect because lactate is produced during anaerobic respiration in humans, not during fermentation in bacteria or other microorganisms.

Question 10

In anaerobic conditions, skeletal muscle produces

Accepted Answer

In the absence of oxygen, skeletal muscle undergoes anaerobic glycolysis, which produces lactate as the end product. This lactate is then transported to the liver, where it can be converted back to glucose through the Cori cycle. Ethanol is not produced by skeletal muscle. CO₂ is not a known product of any metabolic pathway.

Question 11

Which of the following descriptions best matches the function of a mutase?

Accepted Answer

A mutase is an enzyme that catalyzes the shifting of a chemical group from one position on a molecule to another. This involves rearranging the bonds within a single molecule, but specifically refers to the movement of a chemical group.

Question 12

Which of the following descriptions best matches the function of a dehydrogenase?

Accepted Answer

Dehydrogenases are enzymes that catalyze the removal of hydrogen atoms (in the form of hydride ions) from a molecule, leading to oxidation. This is different from the functions described in choices A, B, and D.

Question 13

Glycolysis is an anaerobic process used to catabolize glucose.What does it mean for this process to be anaerobic?

Accepted Answer

Glycolysis is considered an anaerobic process because it does not require oxygen to proceed. This means it can occur in the absence of oxygen, allowing cells to produce energy under anaerobic conditions.

Question 14

What purpose does the phosphorylation of glucose to glucose 6-phosphate by the enzyme hexokinase serve as the first step in glycolysis?

Accepted Answer

Phosphorylation of glucose to glucose 6-phosphate by hexokinase helps to trap glucose within the cell because glucose 6-phosphate cannot easily cross the cell membrane, thus driving the uptake of glucose from outside the cell.

Question 15

Which of the following stages in the breakdown of the piece of toast you had for breakfast generates the most ATP?

Accepted Answer

The breakdown of glucose through glycolysis and the citric acid cycle generates a small amount of ATP, while the majority of ATP is produced during oxidative phosphorylation, which occurs in the mitochondria.

Question 16

The final metabolite produced by glycolysis is

Accepted Answer

Pyruvate is the final metabolite produced by glycolysis, after glucose has been converted into two molecules of pyruvate through a series of enzymatic reactions. Acetyl CoA is produced from pyruvate in aerobic conditions through the process of pyruvate oxidation, while 3-phosphoglycerate and glyceraldehyde 3-phosphate are intermediates in the glycolysis pathway.

Question 17

In step 4 of glycolysis, a six-carbon sugar (fructose 1,6-bisphosphate) is cleaved to produce two three-carbon molecules (dihydroxyacetone phosphate and glyceraldehyde 3-phosphate).Which enzyme catalyzes this reaction?

Accepted Answer

Aldolase catalyzes the cleavage of fructose 1,6-bisphosphate into dihydroxyacetone phosphate and glyceraldehyde 3-phosphate.

Question 18

Steps 7 and 10 of glycolysis result in substrate-level phosphorylation.Which of the following best describes this process?

Accepted Answer

Substrate-level phosphorylation is a metabolic process in which ATP is produced by the transfer of a phosphate group from a substrate molecule to ADP. In glycolysis, steps 7 and 10 involve the conversion of 1,3-bisphosphoglycerate to 3-phosphoglycerate and phosphoenolpyruvate to pyruvate, respectively, resulting in the production of ATP through substrate-level phosphorylation. The energy derived from the oxidation of substrates is coupled to the conversion of ADP to ATP. Therefore, option B is the correct choice.

Question 19

Which of the following processes do NOT take place in the mitochondria?

Accepted Answer

Glycogen breakdown occurs in the cytoplasm, not in the mitochondria. The other three processes listed (citric acid cycle, conversion of pyruvate to activated acetyl groups, and oxidation of fatty acids to acetyl CoA) take place in the mitochondria.

Question 20

Which of the following cells rely exclusively on glycolysis to supply them with ATP?

Accepted Answer

Anaerobically growing yeast relies exclusively on glycolysis for ATP production because it does not use oxygen, which is required for oxidative phosphorylation.

Quiz 13: How Cells Obtain Energy From Food

Foods are broken down into simple molecular subunits for distribution and use throughout the body.Which type of simple subunits, listed below, is used preferentially as an energy source?

On a diet consisting of nothing but protein, which of the following is the most likely outcome?

Glycolysis generates more stored energy than it expends.What is the net number of activated carrier molecules produced in this process (number and type of molecules produced minus the number of those molecules used as input) ?

The advantage to the cell of the gradual oxidation of glucose during cellular respiration compared with its combustion to CO₂ and H₂O in a single step is that

Which of the following descriptions best matches the function of a kinase?

Which of the following steps or processes in aerobic respiration include the production of carbon dioxide?

Which reaction does the enzyme phosphoglucose isomerase catalyze?

The conversion of glyceraldehyde 3-phosphate to 1,3 bisphosphoglycerate in step 6 of glycolysis generates a "high-energy" phosphoanhydride bond.Which of the following BEST describes what happens to that bond in step 7?

Select the best option to fill in the blanks of the following statement: Fermentation is a/an process that converts into carbon dioxide and __.

In anaerobic conditions, skeletal muscle produces

Which of the following descriptions best matches the function of a mutase?

Which of the following descriptions best matches the function of a dehydrogenase?

Glycolysis is an anaerobic process used to catabolize glucose.What does it mean for this process to be anaerobic?

What purpose does the phosphorylation of glucose to glucose 6-phosphate by the enzyme hexokinase serve as the first step in glycolysis?

Which of the following stages in the breakdown of the piece of toast you had for breakfast generates the most ATP?

The final metabolite produced by glycolysis is

In step 4 of glycolysis, a six-carbon sugar (fructose 1,6-bisphosphate) is cleaved to produce two three-carbon molecules (dihydroxyacetone phosphate and glyceraldehyde 3-phosphate) .Which enzyme catalyzes this reaction?

Steps 7 and 10 of glycolysis result in substrate-level phosphorylation.Which of the following best describes this process?

Which of the following processes do NOT take place in the mitochondria?

Which of the following cells rely exclusively on glycolysis to supply them with ATP?

Quiz 13: How Cells Obtain Energy From Food

Foods are broken down into simple molecular subunits for distribution and use throughout the body.Which type of simple subunits, listed below, is used preferentially as an energy source?

On a diet consisting of nothing but protein, which of the following is the most likely outcome?

Glycolysis generates more stored energy than it expends.What is the net number of activated carrier molecules produced in this process (number and type of molecules produced minus the number of those molecules used as input) ?

The advantage to the cell of the gradual oxidation of glucose during cellular respiration compared with its combustion to CO2 and H2O in a single step is that

Which of the following descriptions best matches the function of a kinase?

Which of the following steps or processes in aerobic respiration include the production of carbon dioxide?

Which reaction does the enzyme phosphoglucose isomerase catalyze?

The conversion of glyceraldehyde 3-phosphate to 1,3 bisphosphoglycerate in step 6 of glycolysis generates a "high-energy" phosphoanhydride bond.Which of the following BEST describes what happens to that bond in step 7?

Select the best option to fill in the blanks of the following statement: Fermentation is a/an __________ process that converts __________into carbon dioxide and __________.

In anaerobic conditions, skeletal muscle produces

Which of the following descriptions best matches the function of a mutase?

Which of the following descriptions best matches the function of a dehydrogenase?

Glycolysis is an anaerobic process used to catabolize glucose.What does it mean for this process to be anaerobic?

What purpose does the phosphorylation of glucose to glucose 6-phosphate by the enzyme hexokinase serve as the first step in glycolysis?

Which of the following stages in the breakdown of the piece of toast you had for breakfast generates the most ATP?

The final metabolite produced by glycolysis is

In step 4 of glycolysis, a six-carbon sugar (fructose 1,6-bisphosphate) is cleaved to produce two three-carbon molecules (dihydroxyacetone phosphate and glyceraldehyde 3-phosphate) .Which enzyme catalyzes this reaction?

Steps 7 and 10 of glycolysis result in substrate-level phosphorylation.Which of the following best describes this process?

Which of the following processes do NOT take place in the mitochondria?

Which of the following cells rely exclusively on glycolysis to supply them with ATP?

The advantage to the cell of the gradual oxidation of glucose during cellular respiration compared with its combustion to CO₂ and H₂O in a single step is that

Select the best option to fill in the blanks of the following statement: Fermentation is a/an process that converts into carbon dioxide and __.