Question 1

Which of the following statements best describes the role of the malate-aspartate shuttle in cellular metabolism?

Accepted Answer

It moves NADH produced in the cytosol into the mitochondrial matrix for oxidative phosphorylation.

Question 2

Given the following reaction in the TCA cycle: $$	ext{Isocitrate} ightarrow 	ext{α-Ketoglutarate}$$, which enzyme catalyzes this reaction and what is the main product besides α-Ketoglutarate?

Accepted Answer

Isocitrate dehydrogenase; NADH

Question 3

A cell has a high concentration of ATP and low concentration of ADP. How will this affect the TCA cycle?

Accepted Answer

The TCA cycle will slow down due to allosteric inhibition by ATP.

Question 4

Which of the following best explains the difference between substrate-level phosphorylation and oxidative phosphorylation?

Accepted Answer

Substrate-level phosphorylation directly transfers a phosphate group to ADP, while oxidative phosphorylation uses a proton gradient generated by the electron transport chain to synthesize ATP.

Question 5

Which equation correctly relates the standard free energy change ($$\Delta G^\circ) to $$the equilibrium constant ($$K$$)?

Accepted Answer

$$\Delta G^\circ = -RT \ln K$$

Question 6

During beta-oxidation, which of the following is the correct sequence of reactions for the degradation of a fatty acid?

Accepted Answer

Oxidation, hydration, oxidation, thiolysis

Question 7

A patient is unable to transport fatty acids into the mitochondrial matrix for beta-oxidation. Which molecule is most likely deficient?

Accepted Answer

Carnitine

Question 8

Which of the following is NOT a product of ketone body synthesis from acetyl-CoA?

Accepted Answer

Malate

Question 9

Which enzyme is responsible for the carboxylation of acetyl-CoA to malonyl-CoA during fatty acid synthesis?

Accepted Answer

Acetyl-CoA Carboxylase (ACC)

Question 10

In photosynthesis, what is the ultimate electron acceptor in the non-cyclic electron flow involving Photosystem II and Photosystem I?

Accepted Answer

NADP+

Question 11

Which pigment is primarily responsible for capturing light energy in the light reactions of photosynthesis?

Accepted Answer

Chlorophyll a

Question 12

Which of the following best describes the function of Rubisco in the Calvin Cycle?

Accepted Answer

It catalyzes the fixation of CO2 to ribulose-1,5-bisphosphate.

Question 13

Which of the following amino acids is classified as ketogenic but not glucogenic?

Accepted Answer

Leucine

Question 14

Transamination reactions typically involve which pair of molecules?

Accepted Answer

An amino acid and an α-keto acid

Question 15

Which of the following equations correctly describes the relationship between the actual free energy change ($$\Delta G$$), the standard free energy change ($$\Delta G^\circ$$), and the reaction quotient ($$Q$$)?

Accepted Answer

$$\Delta G = \Delta G^\circ + RT \ln Q$$

Question 16

Which process is directly responsible for the generation of a proton gradient across the inner mitochondrial membrane?

Accepted Answer

Electron transport chain (ETC)

Question 17

A defect in the urea cycle can lead to accumulation of which toxic compound in the blood?

Accepted Answer

Ammonia

Question 18

Which of the following statements about nitrogen fixation is correct?

Accepted Answer

It is carried out by certain bacteria, such as Rhizobium, in symbiosis with plants.

Question 19

Which of the following is a key regulatory molecule that inhibits fatty acid oxidation by blocking the carnitine shuttle?

Accepted Answer

Malonyl-CoA

Question 20

Which of the following best describes the glucose-alanine cycle?

Accepted Answer

It transports nitrogen from muscle to liver in the form of alanine, which is converted to glucose in the liver.

Comprehensive Study Notes: TCA Cycle, Electron Transport, Lipid Metabolism, Photosynthesis, and Nitrogen/Amino Acid Metabolism

Study Guide - Practice Questions

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