Question 1

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

Accepted Answer

It packages, modifies, and sorts proteins and lipids for delivery to targeted destinations.

Question 2

A scientist is studying a protein that is synthesized in the cytosol but needs to be secreted from the cell. According to the signal hypothesis, which of the following steps must occur for this protein to enter the endomembrane system?

Accepted Answer

A signal recognition particle (SRP) binds to the signal sequence on the growing polypeptide, pausing translation and directing the ribosome to the rough ER.

Question 3

Which of the following best explains why oxygen is essential for aerobic cellular respiration in eukaryotic cells?

Accepted Answer

Oxygen is the final electron acceptor in the electron transport chain, allowing for the production of water and the maintenance of the proton gradient.

Question 4

A mutation prevents the formation of tight junctions in an animal’s intestinal epithelial cells. Which of the following is the most likely consequence?

Accepted Answer

Water and solutes may leak uncontrollably between cells, compromising the barrier function of the epithelium.

Question 5

Which of the following equations 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 6

A researcher observes that when substrate concentration is very high, the rate of an enzyme-catalyzed reaction no longer increases. What is the most likely explanation for this observation?

Accepted Answer

All enzyme active sites are occupied, so the reaction rate has reached its maximum velocity ($$V_{max}).$$

Question 7

Which of the following best distinguishes between competitive and allosteric inhibition of enzymes?

Accepted Answer

Competitive inhibitors bind to the active site, while allosteric inhibitors bind to a different site, causing a conformational change in the enzyme.

Question 8

During photosynthesis, where and when is oxygen ($$O_2) $$produced?

Accepted Answer

In the thylakoid lumen during the light-dependent reactions as water is split.

Question 9

Which of the following statements about the extracellular matrix (ECM) is correct?

Accepted Answer

The ECM in animal cells provides structural support and helps regulate cell behavior through signaling.

Question 10

A patient’s muscle cells are deprived of oxygen. Which metabolic pathway will allow the cells to continue producing ATP, and what is the byproduct?

Accepted Answer

Fermentation; lactic acid

Question 11

Which of the following best describes the role of Rubisco in photosynthesis?

Accepted Answer

It catalyzes the fixation of carbon dioxide to ribulose-1,5-bisphosphate in the Calvin cycle.

Question 12

Which of the following cell-cell connections allows for the direct transfer of ions and small molecules between adjacent animal cells?

Accepted Answer

Gap junctions

Question 13

A cell is exposed to a signaling molecule that binds to a G-protein-coupled receptor (GPCR) on its surface. Which of the following is most likely to occur next?

Accepted Answer

The GPCR activates a G-protein, which then activates an enzyme to produce a second messenger such as cAMP.

Question 14

Which of the following best describes the difference between catabolic and anabolic pathways?

Accepted Answer

Catabolic pathways release energy by breaking down molecules, while anabolic pathways consume energy to build complex molecules.

Question 15

Which of the following is a correct sequence of the four main steps of cellular respiration in eukaryotic cells?

Accepted Answer

Glycolysis → Pyruvate processing → Citric acid cycle → Electron transport chain

Question 16

A bamboo shark’s digestive enzymes are studied at different pH levels. The results show maximal activity at pH 7, with activity decreasing at both lower and higher pH. What is the most likely explanation for this observation?

Accepted Answer

The enzyme’s active site is most compatible with substrate binding at pH 7, and changes in pH alter the enzyme’s structure and function.

Question 17

Which of the following best explains why phosphorylation is important in cellular metabolism?

Accepted Answer

Phosphorylation can activate or deactivate enzymes and is used to couple exergonic and endergonic reactions.

Question 18

Which of the following statements about the flow of molecules into and out of the nucleus is correct?

Accepted Answer

Small molecules and ions can diffuse through nuclear pores, but large proteins and RNA require specific transport signals to pass through.

Question 19

Which of the following is a key difference between photosynthesis and aerobic cellular respiration?

Accepted Answer

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

Unit 3 Study Guide: Cell Structure, Cell Communication, Metabolism, Cellular Respiration, and Photosynthesis

Guida di studio - Domande di pratica

Study guide - Flashcard