Question 1

Which of the following organelles is NOT considered part of the endomembrane system in eukaryotic cells?

Accepted Answer

Mitochondrion

Question 2

A scientist is using differential centrifugation to separate cellular components. Which of the following statements best explains why nuclei pellet at lower centrifugal forces than mitochondria?

Accepted Answer

Nuclei have a higher sedimentation coefficient $$S$$ due to their larger size and mass.

Question 3

Which process is primarily responsible for the breakdown of misfolded proteins in the rough endoplasmic reticulum?

Accepted Answer

Proteasomal degradation

Question 4

A patient is found to have a defect in the hydroxylation of drugs, leading to poor drug excretion. Which organelle is most likely dysfunctional?

Accepted Answer

Smooth endoplasmic reticulum

Question 5

Which of the following best describes the main function of the Golgi apparatus in protein processing?

Accepted Answer

Protein glycosylation and sorting for final destination

Question 6

During regulated secretion, which event triggers the release of vesicle contents from the cell?

Accepted Answer

A specific external stimulus

Question 7

Which of the following is a key feature of lysosomes that allows them to digest cellular material efficiently?

Accepted Answer

They maintain an internal pH of 4-5.

Question 8

A cell is observed to have an accumulation of hydrogen peroxide ($$\mathrm{H_2O_2}). $$Which organelle is most likely malfunctioning?

Accepted Answer

Peroxisome

Question 9

Which of the following best describes the process of receptor-mediated endocytosis?

Accepted Answer

Clathrin-coated vesicles form around specific ligand-receptor complexes and are pinched off by dynamin.

Question 10

Which of the following equations correctly represents the Svedberg equation used in subcellular fractionation?

Accepted Answer

$$S = \frac{v}{a}$$

Question 11

A mutation disrupts the SNARE complex in neurons. Which process will be most directly affected?

Accepted Answer

Vesicle fusion during neurotransmitter release

Question 12

Which of the following is a function of autophagy in eukaryotic cells?

Accepted Answer

Degradation of damaged organelles

Question 13

A researcher is using density gradient centrifugation to separate lysosomes, mitochondria, and peroxisomes. Which property allows these organelles to be separated in this way?

Accepted Answer

Differences in their buoyant densities

Question 14

Which of the following best describes the role of the smooth endoplasmic reticulum in liver cells during fasting?

Accepted Answer

It helps convert glycogen to glucose for release into the blood.

Question 15

Which of the following toxins causes a massive release of neurotransmitter at the synapse?

Accepted Answer

Latrotoxin

Question 16

Which of the following is a distinguishing feature of the rough endoplasmic reticulum compared to the smooth endoplasmic reticulum?

Accepted Answer

Presence of membrane-bound ribosomes

Question 17

A cell is unable to form S-S bonds in newly synthesized proteins. Which organelle is most likely defective?

Accepted Answer

Rough endoplasmic reticulum

Question 18

Which of the following best describes the direction of anterograde transport in the Golgi apparatus?

Accepted Answer

From the cis-Golgi network (CGN) to the trans-Golgi network (TGN)

Question 19

Which of the following is a primary function of peroxisomes?

Accepted Answer

Oxidation of fatty acids

Question 20

A cell is observed to have defective clathrin assembly. Which process will be most directly impaired?

Accepted Answer

Receptor-mediated endocytosis

The Endomembrane System and Intracellular Protein Transport

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