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1. Which statement is false concerning lactic acid? It is formed during fast gly

ID: 280593 • Letter: 1

Question

1. Which statement is false concerning lactic acid?

It is formed during fast glycolysis

It is formed when hydrogens combine temporarily with pyruvate

It can diffuse into the blood and be carried away from the site of production

It is a by-product of a high rate of protein breakdown

2. Metabolic processes that are considered aerobic include:

           Krebs cycle

            electron transport chain

beta oxidation

all of the above

    3. Which of the following is not a prerequisite for continuous aerobic production of ATP?

                       acetyl COA must be present

                       NAD and FAD must be available

                       oxygen must be present in the tissues

                       cellular enzymes must be present in sufficient concentration

                       all the above are necessary

                

4. This energy system has the most rapid ability to phosphorylate ADP and form ATP:

electron transport chain

ATP-PC

substrate-level phosphorylation via electron transport chain

Krebs cycle

5. Which statement is false concerning oxidative production of ATP in the electron transport chain?

It is a process of ATP production via the transfer of electrons from hydrogen to oxygen

only small amounts of ATP are produced in the ETC

3 ATP are formed for each NADH oxidized in the ETC

2 ATP are formed for each FADH oxidized in the respiratory chain

6. The immediate energy system (ATP-PC) relies on:

   the reactions of glycolysis

                     oxygen availability in the immediate cellular environment

                     the high-energy phosphates stored in muscle cells

                     the oxidation of lactate

7. Which of the following terms is/are associated with the body’s capacity to produce ATP aerobically

maximal oxygen uptake

aerobic capacity

oxygen consumption

all of the above

Explanation / Answer

The correct answers are as follows:

1. (D) It is a product of protein metabolism.

reason: Lactic acid is produced from pyruvate during fermentation and the enzyme lactate dehydrogenase. It is not associated with protein catabolism

2. (B) Electron transport chain.

Reason: beta oxidation is the multistep breakdown of the long chain fatty acids to produce acetyl coA, while Krebs cycle is a series of cyclic reactions which releases energy from the acetyl coA. The first process do not require oxygen, while the second process also have no oxygen requirement but is the previous step of the Electron transport chain, which requires molecular oxygen in the final step as an electron acceptor

3. (A) Acetyl CoaA must be present.

Reason: Acetyl CoA can be formed during the course of the reaction by the breakdown of the carbohydrate and the lipid and to some extent of the proteins, but to continue the aerobic respiration the presence of the other conditions are necessary.

4. (D) Krebs cycle

Reason: Although the Krebs cycle produces one molecule of ATP per molecule of acetyl CoA oxidized, in terms of rapidity it is the swiftest compared to the other processes as substrate level phosphorylation occurs at the step when Succinyl CoA is converted to Succinate.

5. (B)

Reason: During the oxidation of one molecule of glucose, the Krebs cycle produces 2 molecules of ATP, 10 high energy carrier molecule which are then utilized by the ETC complex to produce 34 ATP molecules, thus the bulk of the ATP is produced by the ETC in case of the aerobically respiring organisms.

6. (C) The high energy phosphates stored in the muscle.

Reason: Creatine phosphate is a high energy compound stored in the muscle and it provides a high energy output for a short duration time.

7. (D)

Reason: All the three terms are related to oxygen uptake.