Question 1

Energy that is contained within the chemical bonds of a substance such as ATP may be classified as __________.

Accepted Answer

The energy stored within the chemical bonds of substances like ATP is considered potential energy because it has the potential to do work when those bonds are broken. Kinetic energy is the energy of motion, mechanical energy is a form of kinetic energy related to the movement of objects, and free energy specifically refers to the portion of a system's energy that can perform work when temperature and pressure are uniform throughout the system. Potential energy, on the other hand, is stored energy that is not currently performing work but has the potential to do so, making it the correct classification for the energy within chemical bonds.

Question 2

When exercise becomes intense, pyruvate accepts additional hydrogens, forming __________.

Accepted Answer

During intense exercise, when oxygen supply is insufficient for the demands of the muscles, pyruvate accepts additional hydrogens to form lactate (or lactic acid). This process allows glycolysis to continue producing ATP in the absence of adequate oxygen, a condition known as anaerobic metabolism.

Question 3

Most of the energy for ATP phosphorylation comes from __________ of the carbohydrate, lipid, and protein consumed in the diet.

Accepted Answer

The energy for ATP phosphorylation primarily comes from the oxidation of carbohydrates, lipids, and proteins consumed in the diet. This process involves the removal of electrons (oxidation) from these molecules, which is then used to drive the synthesis of ATP.

Question 4

Highly specific __________ catalyze hydrogen's release from the nutrient substrate.

Accepted Answer

Dehydrogenase coenzymes are highly specific enzymes that catalyze the removal of hydrogen from substrates, which is essential in various biochemical pathways, including cellular respiration.

Question 5

The process of __________ phosphorylation synthesizes ATP by transferring electrons from NADH and FADH₂ to oxygen.

Accepted Answer

The process described is oxidative phosphorylation, which involves the transfer of electrons from NADH and FADH2 to oxygen, leading to the synthesis of ATP. This process occurs in the mitochondria and is a key part of cellular respiration.

Question 6

Glucose breaks down relatively rapidly to two molecules of pyruvate in a process called __________.

Accepted Answer

Glycolysis is the metabolic pathway that converts glucose into pyruvate, releasing energy and pyruvate as end products.

Question 7

__________ is the term used to describe cleavage of glucose from stored glycogen.

Accepted Answer

Glycogenolysis is the metabolic pathway in which glycogen stored in cells is broken down into glucose to be used as energy.

Question 8

The liver cells conserve the potential energy in the lactate and pyruvate molecules formed during exercise as the carbon skeletons of these molecules become synthesized to glucose in the __________.

Accepted Answer

The Cori cycle describes the process where lactate produced by anaerobic glycolysis in the muscles moves to the liver, where it is converted back into glucose. This glucose can then be sent back to the muscles to be used as energy, effectively conserving the energy from lactate and pyruvate.

Question 9

The most important function of the citric acid cycle is to generate __________.

Accepted Answer

The citric acid cycle's primary role is to generate high-energy electrons (in the form of NADH and FADH2) that are used in the electron transport chain to produce ATP.

Question 10

The process called __________ splits the triacylglycerol molecule into glycerol and three water-insoluble fatty acid molecules.

Accepted Answer

Lipolysis is the metabolic process through which triacylglycerol molecules are broken down into glycerol and three fatty acids.

Question 11

Citric acid cycle degradation of fatty acids depends on sufficient __________ availability to combine with the acetyl-CoA formed during $\beta$-oxidation.

Accepted Answer

The citric acid cycle (also known as the Krebs cycle or TCA cycle) requires oxaloacetate to combine with acetyl-CoA, which is formed during fatty acid β-oxidation, to initiate the cycle. This combination forms citrate, which then undergoes a series of reactions to produce energy.

Question 12

During extreme carbohydrate depletion, the acetate fragments produced in $\beta$-oxidation cannot readily enter the citric acid cycle. The liver converts these compounds to __________.

Accepted Answer

During extreme carbohydrate depletion, the liver converts acetate fragments produced in beta-oxidation into ketone bodies. This is because, with limited oxaloacetate (from carbohydrates) to condense with acetyl-CoA in the citric acid cycle, the acetyl-CoA is instead diverted to ketone body synthesis.

Question 13

__________ describes the formation of lipid that occurs mostly in the cytoplasm of liver cells.

Accepted Answer

Lipogenesis is the metabolic process through which acetyl-CoA is converted into triglycerides (fats), primarily occurring in the cytoplasm of liver cells, as well as in adipose tissue.

Question 14

The term to describe reactions that require oxygen is __________.

Accepted Answer

Aerobic reactions are those that require oxygen to proceed. Anaerobic reactions, in contrast, do not require oxygen. Chemical and mechanical are broader terms that do not specifically relate to the presence or absence of oxygen.

Question 15

The purpose for energy released in macronutrient breakdown is to __________.

Accepted Answer

The energy released from macronutrient breakdown is primarily used to phosphorylate ADP to form ATP, which is the main energy currency of the cell.

Question 16

When deaminated, some amino acids yield intermediate products for the synthesis of __________.

Accepted Answer

When deaminated, some amino acids yield intermediate products that can be used in the synthesis of glucose through a process known as gluconeogenesis. This is important for maintaining blood sugar levels, especially during periods of fasting or intense exercise.

Question 17

Without the availability of __________ for phosphorylation to ATP, electrons do not travel down the respiratory chain to oxygen.

Accepted Answer

ADP (adenosine diphosphate) is essential for the phosphorylation process to ATP (adenosine triphosphate) in cellular respiration. Without ADP, the electron transport chain cannot function properly, as it relies on the phosphorylation of ADP to ATP to maintain the flow of electrons towards oxygen.

Question 18

The first law of thermodynamics states that __________.

Accepted Answer

The first law of thermodynamics, also known as the law of energy conservation, states that energy cannot be created or destroyed in an isolated system, but can only be transformed from one form to another. This principle underlies the concept that the total energy of an isolated system remains constant.

Question 19

Toward the end of prolonged physical effort (with glycogen reserves low), circulating FFAs supply nearly __________% of the total energy required.

Accepted Answer

During prolonged physical effort, especially when glycogen reserves are low, circulating free fatty acids (FFAs) become a primary energy source, supplying nearly 80% of the total energy required. This shift occurs as the body seeks to preserve its limited glycogen stores and relies more heavily on fat metabolism.

Question 20

All of the following represent forms of biologic work except __________.

Accepted Answer

Osmotic work involves the movement of water across a semipermeable membrane due to osmotic pressure differences, which is a passive process and not considered a form of biological work in the same way that mechanical, chemical, and transport work are. These latter forms require energy expenditure, typically in the form of ATP hydrolysis, to perform specific tasks within the organism.

Quiz 4: Nutrient Role in Bioenergetics

Energy that is contained within the chemical bonds of a substance such as ATP may be classified as __________.

When exercise becomes intense, pyruvate accepts additional hydrogens, forming __________.

Most of the energy for ATP phosphorylation comes from __________ of the carbohydrate, lipid, and protein consumed in the diet.

Highly specific __________ catalyze hydrogen's release from the nutrient substrate.

The process of __________ phosphorylation synthesizes ATP by transferring electrons from NADH and FADH₂ to oxygen.

Glucose breaks down relatively rapidly to two molecules of pyruvate in a process called __________.

__________ is the term used to describe cleavage of glucose from stored glycogen.

The liver cells conserve the potential energy in the lactate and pyruvate molecules formed during exercise as the carbon skeletons of these molecules become synthesized to glucose in the __________.

The most important function of the citric acid cycle is to generate __________.

The process called __________ splits the triacylglycerol molecule into glycerol and three water-insoluble fatty acid molecules.

Citric acid cycle degradation of fatty acids depends on sufficient __________ availability to combine with the acetyl-CoA formed during $\beta$ -oxidation.

During extreme carbohydrate depletion, the acetate fragments produced in $\beta$ -oxidation cannot readily enter the citric acid cycle. The liver converts these compounds to __________.

__________ describes the formation of lipid that occurs mostly in the cytoplasm of liver cells.

The term to describe reactions that require oxygen is __________.

The purpose for energy released in macronutrient breakdown is to __________.

When deaminated, some amino acids yield intermediate products for the synthesis of __________.

Without the availability of __________ for phosphorylation to ATP, electrons do not travel down the respiratory chain to oxygen.

The first law of thermodynamics states that __________.

Toward the end of prolonged physical effort (with glycogen reserves low) , circulating FFAs supply nearly __________% of the total energy required.

All of the following represent forms of biologic work except __________.

Quiz 4: Nutrient Role in Bioenergetics

Energy that is contained within the chemical bonds of a substance such as ATP may be classified as __________.

When exercise becomes intense, pyruvate accepts additional hydrogens, forming __________.

Most of the energy for ATP phosphorylation comes from __________ of the carbohydrate, lipid, and protein consumed in the diet.

Highly specific __________ catalyze hydrogen's release from the nutrient substrate.

The process of __________ phosphorylation synthesizes ATP by transferring electrons from NADH and FADH2 to oxygen.

Glucose breaks down relatively rapidly to two molecules of pyruvate in a process called __________.

__________ is the term used to describe cleavage of glucose from stored glycogen.

The liver cells conserve the potential energy in the lactate and pyruvate molecules formed during exercise as the carbon skeletons of these molecules become synthesized to glucose in the __________.

The most important function of the citric acid cycle is to generate __________.

The process called __________ splits the triacylglycerol molecule into glycerol and three water-insoluble fatty acid molecules.

Citric acid cycle degradation of fatty acids depends on sufficient __________ availability to combine with the acetyl-CoA formed during β\betaβ -oxidation.

During extreme carbohydrate depletion, the acetate fragments produced in β\betaβ -oxidation cannot readily enter the citric acid cycle. The liver converts these compounds to __________.

__________ describes the formation of lipid that occurs mostly in the cytoplasm of liver cells.

The term to describe reactions that require oxygen is __________.

The purpose for energy released in macronutrient breakdown is to __________.

When deaminated, some amino acids yield intermediate products for the synthesis of __________.

Without the availability of __________ for phosphorylation to ATP, electrons do not travel down the respiratory chain to oxygen.

The first law of thermodynamics states that __________.

Toward the end of prolonged physical effort (with glycogen reserves low) , circulating FFAs supply nearly __________% of the total energy required.

All of the following represent forms of biologic work except __________.

The process of __________ phosphorylation synthesizes ATP by transferring electrons from NADH and FADH₂ to oxygen.

Citric acid cycle degradation of fatty acids depends on sufficient __________ availability to combine with the acetyl-CoA formed during $\beta$ -oxidation.

During extreme carbohydrate depletion, the acetate fragments produced in $\beta$ -oxidation cannot readily enter the citric acid cycle. The liver converts these compounds to __________.