Question 1

Which of the following best describes the function of the Golgi apparatus in a eukaryotic cell?

Accepted Answer

It modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.

Question 2

A scientist observes a eukaryotic cell engulfing a large bacterium. Which process is most likely occurring, and which organelle will digest the bacterium?

Accepted Answer

Phagocytosis; lysosome

Question 3

Which of the following statements about the nuclear envelope is correct?

Accepted Answer

It is a double membrane with nuclear pores that regulate the transport of RNA and proteins.

Question 4

During the signal hypothesis, which step involves the recognition of the signal sequence by the signal recognition particle (SRP)?

Accepted Answer

Step 3

Question 5

Which type of cell-cell connection in animal tissues allows the direct transfer of ions and small molecules between adjacent cells?

Accepted Answer

Gap junctions

Question 6

A mutation causes a plant cell to lack functional plasmodesmata. Which of the following is a likely consequence?

Accepted Answer

The cell will have impaired communication and transport of molecules with adjacent cells.

Question 7

Which of the following best describes the role of G-protein-coupled receptors (GPCRs) in cell signaling?

Accepted Answer

They activate G-proteins, which then trigger the production of second messengers inside the cell.

Question 8

Which equation correctly represents the relationship between Gibbs free energy ($$\Delta G$$), enthalpy ($$\Delta H$$), entropy ($$\Delta S$$), and temperature ($$T$$)?

Accepted Answer

$$\Delta G = \Delta H - T\Delta S$$

Question 9

A chemical reaction has $$\Delta G = -15 kJ/$$mol. Which of the following statements is true about this reaction?

Accepted Answer

The reaction is exergonic and spontaneous.

Question 10

In a metabolic pathway, ATP hydrolysis is coupled to an endergonic reaction. Which statement best explains how this coupling makes the overall process spontaneous?

Accepted Answer

The negative $$\Delta G$$ from ATP hydrolysis offsets the positive $$\Delta G of $$the endergonic reaction, resulting in a net negative $$\Delta G.$$

Question 11

Which of the following best describes how enzymes increase the rate of biological reactions?

Accepted Answer

They lower the activation energy required for the reaction to proceed.

Question 12

A researcher finds that increasing substrate concentration no longer increases the rate of an enzyme-catalyzed reaction. What is the most likely explanation?

Accepted Answer

The enzyme is saturated with substrate; all active sites are occupied.

Question 13

Which of the following is an example of allosteric regulation of an enzyme?

Accepted Answer

A molecule binds to a site other than the active site, causing a conformational change that affects enzyme activity.

Question 14

Which of the following best distinguishes catabolic from anabolic pathways in metabolism?

Accepted Answer

Catabolic pathways break down molecules to release energy, while anabolic pathways build complex molecules from simpler ones.

Question 15

Which of the following lists the correct order and location of the four steps of cellular respiration in eukaryotic cells?

Accepted Answer

Glycolysis (cytosol), Pyruvate processing (mitochondrial matrix), Citric acid cycle (mitochondrial matrix), Electron transport chain (inner mitochondrial membrane)

Question 16

Why is oxygen essential for aerobic cellular respiration?

Accepted Answer

It acts as the final electron acceptor in the electron transport chain, allowing ATP production to continue.

Question 17

When oxygen is scarce, cells switch to fermentation. What is the primary purpose of fermentation in this context?

Accepted Answer

To regenerate NAD$$^+ so $$glycolysis can continue.

Question 18

Which of the following statements about photosynthesis is correct?

Accepted Answer

Oxygen is produced during the light-dependent reactions in the thylakoid membranes.

Question 19

Which enzyme is responsible for carbon fixation in the Calvin cycle, and what is a major consequence if this enzyme catalyzes photorespiration instead?

Accepted Answer

Rubisco; reduced efficiency of photosynthesis due to loss of fixed carbon

Question 20

Which of the following best compares photosynthesis and aerobic cellular respiration?

Accepted Answer

Photosynthesis is endergonic and stores energy in glucose, while respiration is exergonic and releases energy from glucose.

General Biology: Cell Structure, Cell Communication, Metabolism, Respiration, and Photosynthesis

Guida di studio - Domande di pratica

Study guide - Flashcard