Q: During glycolysis, substrate-level phosphorylation occurs when a phosphate group is transferred from a high-energy intermediate to ADP. Which equation represents this process?

$$\text{High-energy intermediate} + \text{ADP} \rightarrow \text{Product} + \text{ATP}$$

Q: During the Citric Acid cycle, substrate-level phosphorylation occurs at the conversion of succinyl-CoA to succinate. Which equation represents the synthesis of ATP (or GTP) in this step?

$$\text{Succinyl-CoA} + \text{ADP} + \text{Pi} \rightarrow \text{Succinate} + \text{CoA} + \text{ATP}$$

Question 1

Which of the following best describes the primary function of the rough endoplasmic reticulum (RER) in eukaryotic cells?

Accepted Answer

Protein synthesis, folding, and transport via membrane vesicles

Question 2

A patient is diagnosed with a lysosomal storage disease due to a deficiency in a specific lysosomal enzyme. Which cellular process is most directly affected?

Accepted Answer

Digestion and recycling of cellular materials (autophagy and heterophagy)

Question 3

Which of the following statements about the Golgi apparatus is correct?

Accepted Answer

It consists of stacks of flattened membrane sacs with cis and trans faces, and is responsible for processing, sorting, and packaging proteins and lipids.

Question 4

Which cytoskeletal element is primarily responsible for maintaining cell shape and resisting mechanical stress, and is composed of fibrous proteins such as keratin?

Accepted Answer

Intermediate filaments

Question 5

Motor proteins such as kinesin and dynein move vesicles along microtubules using energy from ATP hydrolysis. Which direction does kinesin typically move relative to the microtubule polarity?

Accepted Answer

Toward the plus end (cell periphery)

Question 6

According to the first law of thermodynamics, which equation correctly represents the relationship between internal energy, heat, and work in a cell?

Accepted Answer

$$\Delta U = Q - W$$

Question 7

Which of the following best explains why the hydrolysis of ATP is highly exergonic?

Accepted Answer

ATP contains unstable bonds due to repulsion between negatively charged phosphate groups, and hydrolysis releases this repulsion, increasing entropy.

Question 8

During glycolysis, substrate-level phosphorylation occurs when a phosphate group is transferred from a high-energy intermediate to ADP. Which equation represents this process?

Accepted Answer

$$	ext{High-energy intermediate} + 	ext{ADP} ightarrow 	ext{Product} + 	ext{ATP}$$

Question 9

Which regulatory enzyme in glycolysis is most sensitive to the energy charge (ATP/AMP ratio) of the cell?

Accepted Answer

Phosphofructokinase-1 (PFK-1)

Question 10

Why are bypass steps needed in gluconeogenesis instead of simply reversing glycolysis?

Accepted Answer

Some steps in glycolysis are highly exergonic and irreversible, so gluconeogenesis uses different enzymes to bypass these steps.

Question 11

A muscle cell deprived of oxygen will convert pyruvate to lactic acid. What is the primary purpose of this conversion?

Accepted Answer

To regenerate NAD+ for continued glycolysis

Question 12

Which of the following best describes the amphibolic nature of the Citric Acid cycle?

Accepted Answer

It serves both catabolic and anabolic functions, providing intermediates for biosynthesis and energy production.

Question 13

During the Citric Acid cycle, substrate-level phosphorylation occurs at the conversion of succinyl-CoA to succinate. Which equation represents the synthesis of ATP (or GTP) in this step?

Accepted Answer

$$	ext{Succinyl-CoA} + 	ext{ADP} + 	ext{Pi} ightarrow 	ext{Succinate} + 	ext{CoA} + 	ext{ATP}$$

Question 14

Which complex in the mitochondrial electron transport chain (ETC) is both an enzyme of the Citric Acid cycle and a component of the ETC?

Accepted Answer

Complex II (succinate dehydrogenase)

Question 15

The proton gradient generated by the ETC is used to drive ATP synthesis. Which equation best represents the process catalyzed by ATP synthase (Complex V)?

Accepted Answer

$$	ext{ADP} + 	ext{Pi} ightarrow 	ext{ATP}$$

Question 16

Which of the following statements about peroxisomes is correct?

Accepted Answer

Peroxisomes contain catalase to convert peroxides to water and defend against oxidative damage.

Question 17

Which process in photosynthesis is directly responsible for the generation of oxygen in the biosphere?

Accepted Answer

The splitting of water by Photosystem II (PSII)

Question 18

Chlorophyll P680 and P700 are found in PSII and PSI, respectively. What do these numbers represent?

Accepted Answer

The wavelength (in nm) at which the 'special pair' chlorophyll absorbs light most efficiently

Question 19

Which equation best represents the assimilation of carbon dioxide into carbohydrates during the Calvin Cycle?

Accepted Answer

$$6	ext{CO}_2 + 12	ext{NADPH} + 18	ext{ATP} ightarrow 	ext{C}_6	ext{H}_{12}	ext{O}_6 + 12	ext{NADP}^+ + 18	ext{ADP} + 18	ext{Pi}$$

ABS 311 Molecular and Cellular Biology: Exam 2 Study Guide

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