Question 1

Which of the following statements best explains why water is essential for life as we know it?

Accepted Answer

Water is a universal solvent that facilitates the formation and breaking of bonds in biological polymers through dehydration and hydrolysis reactions.

Question 2

Which of the following best describes the role of ATP in cellular metabolism?

Accepted Answer

ATP acts as a universal energy currency, storing energy in its phosphate bonds and releasing it to drive endergonic reactions.

Question 3

During glycolysis, what is the net gain of ATP molecules produced per molecule of glucose?

Accepted Answer

$$2$$

Question 4

Which enzyme is responsible for the irreversible phosphorylation of glucose in the first step of glycolysis, and how does its regulation impact glycolytic flux?

Accepted Answer

Hexokinase; its high affinity for glucose ensures glycolysis proceeds even at low glucose concentrations.

Question 5

Which of the following best explains why the citric acid cycle (CAC) is considered a central metabolic pathway?

Accepted Answer

It oxidizes acetyl-CoA from carbohydrates, fats, and proteins, generating NADH and FADH$$_2$$ for ATP production.

Question 6

Which of the following statements about the electron transport chain (ETC) is correct?

Accepted Answer

The ETC transfers electrons from NADH and FADH$$_2 to $$oxygen, pumping protons across the mitochondrial inner membrane to generate a proton gradient.

Question 7

A poison that inhibits Complex IV of the electron transport chain would have which of the following effects?

Accepted Answer

It would prevent the transfer of electrons to oxygen, halting ATP synthesis and causing cell death.

Question 8

Which process in photosynthesis is responsible for the production of ATP and NADPH?

Accepted Answer

The light reactions, which occur in the thylakoid membranes of chloroplasts.

Question 9

Which of the following best describes the main function of the Calvin cycle in photosynthesis?

Accepted Answer

To fix CO$$_2$$ into organic molecules using ATP and NADPH produced in the light reactions.

Question 10

Which of the following is a correct statement about the regulation of blood glucose levels in humans?

Accepted Answer

Insulin lowers blood glucose by promoting glucose uptake and storage, while glucagon raises blood glucose by stimulating glycogen breakdown and gluconeogenesis.

Question 11

Which of the following best explains why C$$_4$$ plants are more efficient than C$$_3$$ plants in hot, dry environments?

Accepted Answer

C$$_4$$ plants concentrate CO$$_2 in $$bundle-sheath cells, reducing photorespiration and increasing photosynthetic efficiency.

Question 12

Which of the following is a direct result of a mutation in the gene encoding an enzyme in the glycolytic pathway?

Accepted Answer

A block in glycolysis, leading to reduced ATP production and possible accumulation of upstream metabolites.

Question 13

Which of the following equations correctly represents the overall reaction for aerobic cellular respiration?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$} + 6\mathrm{O_2$} ightarrow 6\mathrm{CO_2$} + 6\mathrm{H_2O} + 	ext{energy (ATP)}$$

Question 14

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

Accepted Answer

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

Question 15

A patient with a genetic defect in the enzyme lactase cannot digest lactose. Which type of mutation is most likely responsible for this condition?

Accepted Answer

A mutation in the gene encoding lactase, leading to a nonfunctional enzyme and inability to hydrolyze lactose.

Question 16

Which of the following best explains why fermentation is less efficient than aerobic respiration in terms of ATP yield?

Accepted Answer

Fermentation only produces ATP via substrate-level phosphorylation and does not utilize the electron transport chain.

Question 17

Which of the following is a real-world application of understanding bioenergetics in medicine?

Accepted Answer

Developing treatments for mitochondrial diseases by targeting defects in ATP production.

BIOSCI 101: Life! Origins and Mechanisms – Mini-Textbook Study Notes

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드