Question 1

Use the following to answer the questions below:
In each of the following multiple-choice questions, characterize EACH of the three given statements as being TRUE or FALSE and then indicate the collective true-false status of the statements using the choices:
-Statements:
(1) The ketone body acetoacetate lowers blood pH because of the presence of a carboxyl (acid) group in its structure.
(2) Two products of the initial "turn" in the $\beta$-oxidation pathway are acetyl CoA and a fatty acid that contains two more carbon atoms than the reactant fatty acid.
(3) Fatty acids produced through lipogenesis cannot contain more than 14 carbon atoms.

Accepted Answer

Statement (1) is true because acetoacetate is a ketone body that can lower blood pH due to its acidic nature. Statement (2) is false; the products are acetyl CoA and a fatty acid with two fewer carbon atoms. Statement (3) is false; fatty acids can contain more than 14 carbon atoms.

Question 2

Use the following to answer the questions below:
For each of the substances, select from the response list the process with which it is associated. Responses may be used more than once or need not be used at all.

-Malonyl CoA

Accepted Answer

Malonyl CoA is involved in the process of lipogenesis, which is the synthesis of fatty acids.

Question 3

Use the following to answer the questions below:
In each of the following multiple-choice questions, characterize EACH of the three given statements as being TRUE or FALSE and then indicate the collective true-false status of the statements using the choices:
-Statements: (1) When the amount of acetyl CoA is excessive compared with the amount of oxaloacetate available to react with it, ketone body formation occurs.
(2) The transport stage of fatty acid oxidation involves the shuttle molecule acyl carnitine.
(3) As a part of digestion of lipids, enzymes in bile help "solubilize" the lipids.

Accepted Answer

Statement 1 is true because excess acetyl CoA leads to ketone body formation when oxaloacetate is insufficient. Statement 2 is true as acyl carnitine is involved in the transport of fatty acids into mitochondria. Statement 3 is false because bile acids, not enzymes, help solubilize lipids.

Question 4

Use the following to answer the questions below:
Identify the step (1 through 4) in a "turn" in the $\beta$-oxidation pathway at which each of the compounds would be encountered as a reactant using the response list. Responses may be used more than once or need not be used at all.

-How many acetyl CoA are produced?

Accepted Answer

In the F1F1F1S1β-oxidation pathway, each turn (cycle) of β-oxidation cleaves off a two-carbon unit from the fatty acid chain, converting it into acetyl CoA. The given compound, F1F1F1S1βF1F1F10, has a total of 16 carbons (as indicated by the "F10" at the end, with the preceding "F1F1F1S1βF1" indicating a specific structure that doesn't change the total carbon count for the purpose of counting acetyl CoA production). Since each turn produces one acetyl CoA and you start with a 16-carbon fatty acid, you would get 8 acetyl CoA molecules after complete oxidation (16 carbons / 2 carbons per acetyl CoA = 8 acetyl CoA).

Question 5

Use the following to answer the questions below:
For each of the substances, select from the response list the process with which it is associated. Responses may be used more than once or need not be used at all.

-Dihydroxyacetone phosphate

Accepted Answer

Dihydroxyacetone phosphate is associated with glycerol degradation, as it is a key intermediate in the metabolic pathway that converts glycerol into glycolytic intermediates.

Question 6

Use the following to answer the questions below:
On the left are characteristics of various reactions that occur in the chain elongation phase of fatty acid biosynthesis. Identify the step (1 through 4) of the chain elongation process to which each characterization applies using the response list on the right. Responses on the right may be used more than once or need not be used at all.

-Malonyl ACP is a reactant.

Accepted Answer

Malonyl ACP is used as a reactant in step 1 of the chain elongation process in fatty acid biosynthesis.

Question 7

Use the following to answer the questions below:
For each of the substances, select from the response list the process with which it is associated. Responses may be used more than once or need not be used at all.

-Carnitine

Accepted Answer

Carnitine is associated with the β-oxidation pathway, which is the process by which fatty acids are broken down into acetyl-CoA for energy production. Carnitine plays a crucial role in transporting fatty acids into the mitochondria where β-oxidation occurs. Choices A and B are involved in the synthesis of fatty acids, while choice D relates to the breakdown of glycerol, a component of triglycerides.

Question 8

Use the following to answer the questions below:
In each of the following multiple-choice questions, characterize EACH of the three given statements as being TRUE or FALSE and then indicate the collective true-false status of the statements using the choices:
-Statements: (1) The functional group change sequence "alkane-alkene-primary alcohol-ketone" occurs during each "turn" of the $\beta$-oxidation pathway.
(2) Squalene and lanosterol, intermediates in cholesterol biosynthesis, contain more carbon atoms than does cholesterol.
(3) The acetyl CoA needed for lipogenesis is shuttled from mitochondria to the cytosol via a citrate shuttle.

Accepted Answer

Statement (1) is false because the sequence described does not occur in the β-oxidation pathway. Statement (2) is true as both squalene and lanosterol have more carbon atoms than cholesterol. Statement (3) is true because acetyl CoA is transported from mitochondria to the cytosol via the citrate shuttle for lipogenesis.

Question 9

Use the following to answer the questions below:
For each of the substances, select from the response list the process with which it is associated. Responses may be used more than once or need not be used at all.

-Glycerol 3-phosphate

Accepted Answer

The answer of Use the following to answer the questions...

Question 10

Use the following to answer the questions below:
In each of the following multiple-choice questions, characterize EACH of the three given statements as being TRUE or FALSE and then indicate the collective true-false status of the statements using the choices:
-Statements: (1) The human body, in the resting state, burns more fat than carbohydrate.
(2) The initial stages of exercise are fueled primarily by glucose.
(3) Statins lower plasma concentrations of LDL by inhibiting cholesterol synthesis in the liver.

Accepted Answer

Statement 1 is true as the body primarily uses fat for energy at rest. Statement 2 is true because the body initially uses glucose for quick energy during exercise. Statement 3 is true as statins inhibit HMG-CoA reductase, reducing cholesterol synthesis and lowering LDL levels.

Question 11

Use the following to answer the questions below: In each of the following multiple-choice questions, characterize EACH of the three given statements as being TRUE or FALSE and then indicate the collective true-false status of the statements using the choices: -Statements: (1) The products of the first two stages of cholesterol biosynthesis are, respectively, mevalonate (C₆) and isopentenyl pyrophosphate (C₅). (2) Over 90 percent of total dietary lipids are triacylglycerols. (3) The activation stage of fatty acid oxidation involves both CoA and ATP.

Accepted Answer

(1) True - mevalonate and isopentenyl pyrophosphate are indeed products of the first two stages of cholesterol biosynthesis.
(2) True - over 90 percent of total dietary lipids are indeed triacylglycerols.
(3) True - both CoA and ATP are indeed involved in the activation stage of fatty acid oxidation.

Therefore, all three statements are true.

Question 12

Use the following to answer the questions below: Identify the step (1 through 4) in a "turn" in the $\beta$-oxidation pathway at which each of the compounds would be encountered as a reactant using the response list. Responses may be used more than once or need not be used at all. -What is the net ATP production for complete degradation of the fatty acid to CO₂ and H₂O?

Accepted Answer

The complete degradation of a fatty acid like palmitic acid (16 carbons) through β-oxidation, the citric acid cycle, and oxidative phosphorylation yields approximately 106 ATP molecules.

Question 13

Use the following to answer the questions below: On the left are characteristics of various reactions that occur in the chain elongation phase of fatty acid biosynthesis. Identify the step (1 through 4) of the chain elongation process to which each characterization applies using the response list on the right. Responses on the right may be used more than once or need not be used at all. -CO₂ is a product.

Accepted Answer

The product CO₂ indicates the involvement of a malonyl/acetyl-CoA molecule, which is characteristic of the initial step (condensation) in the fatty acid chain elongation process.

Question 14

Use the following to answer the questions below:
On the left are characteristics of various reactions that occur in the chain elongation phase of fatty acid biosynthesis. Identify the step (1 through 4) of the chain elongation process to which each characterization applies using the response list on the right. Responses on the right may be used more than once or need not be used at all.

-ACP is a product.

Accepted Answer

ACP (acyl carrier protein) is involved in the initial step of the chain elongation phase of fatty acid biosynthesis, where it carries the growing fatty acid chain.

Question 15

Use the following to answer the questions below: Identify the step (1 through 4) in a "turn" in the $\beta$-oxidation pathway at which each of the compounds would be encountered as a reactant using the response list. Responses may be used more than once or need not be used at all. -How many FADH₂ are produced?

Accepted Answer

In the β-oxidation pathway, each turn of the cycle produces 1 FADH2. For a 16-carbon fatty acid like palmitic acid, 7 cycles are required, producing 7 FADH2 molecules.

Question 16

Use the following to answer the questions below:
For each of the substances, select from the response list the process with which it is associated. Responses may be used more than once or need not be used at all.

-Acetoacetyl ACP

Accepted Answer

Acetoacetyl ACP is associated with lipogenesis, the process of synthesizing fatty acids from acetyl-CoA units.

Question 17

Use the following to answer the questions below:
Identify the step (1 through 4) in a "turn" in the $\beta$-oxidation pathway at which each of the compounds would be encountered as a reactant using the response list. Responses may be used more than once or need not be used at all.

-How many NADH are produced?

Accepted Answer

In the β-oxidation of a fatty acid with 16 carbons (palmitic acid), 7 cycles of β-oxidation occur, producing 7 NADH molecules.

Question 18

Use the following to answer the questions below:
On the left are characteristics of various reactions that occur in the chain elongation phase of fatty acid biosynthesis. Identify the step (1 through 4) of the chain elongation process to which each characterization applies using the response list on the right. Responses on the right may be used more than once or need not be used at all.

-A dehydration reaction occurs.

Accepted Answer

The dehydration reaction occurs in step 3 of the fatty acid chain elongation process, where a hydroxyl group is removed to form a double bond.

Question 19

Use the following to answer the questions below:
On the left are characteristics of various reactions that occur in the chain elongation phase of fatty acid biosynthesis. Identify the step (1 through 4) of the chain elongation process to which each characterization applies using the response list on the right. Responses on the right may be used more than once or need not be used at all.

-A carbon-carbon double bond is converted to a carbon-carbon single bond.

Accepted Answer

A carbon-carbon double bond is converted to a carbon-carbon single bond in step 4 of the chain elongation process.

Question 20

Use the following to answer the questions below:
Identify the step (1 through 4) in a "turn" in the $\beta$-oxidation pathway at which each of the compounds would be encountered as a reactant using the response list. Responses may be used more than once or need not be used at all.

-How many "turns" in the$\beta$-oxidation pathway are needed?

Accepted Answer

The question seems to be incorrectly formatted or contains a typographical error in the pathway name ("F1F1F1S1uf062F1F1F10-oxidation pathway"), making it challenging to provide a specific answer. However, in general, the first step in a beta-oxidation pathway involves the introduction of a compound as a reactant, which aligns with option A. Beta-oxidation typically starts with the activation of a fatty acid, which then enters the cycle for degradation.

Quiz 25: Lipid Metabolism

Use the following to answer the questions below: For each of the substances, select from the response list the process with which it is associated. Responses may be used more than once or need not be used at all. -Malonyl CoA

Use the following to answer the questions below: For each of the substances, select from the response list the process with which it is associated. Responses may be used more than once or need not be used at all. -Dihydroxyacetone phosphate

Use the following to answer the questions below: For each of the substances, select from the response list the process with which it is associated. Responses may be used more than once or need not be used at all. -Carnitine

Use the following to answer the questions below: For each of the substances, select from the response list the process with which it is associated. Responses may be used more than once or need not be used at all. -Glycerol 3-phosphate

Use the following to answer the questions below: For each of the substances, select from the response list the process with which it is associated. Responses may be used more than once or need not be used at all. -Acetoacetyl ACP