Question 1

Which of the following best describes the main function of the endomembrane system in eukaryotic cells?

Accepted Answer

It coordinates the synthesis, modification, and transport of proteins and lipids within the cell.

Question 2

Which organelle is primarily responsible for the detoxification of drugs and poisons in liver cells?

Accepted Answer

Smooth endoplasmic reticulum

Question 3

A protein destined for secretion from a cell is synthesized by ribosomes attached to which structure?

Accepted Answer

Rough endoplasmic reticulum

Question 4

Which of the following correctly matches the organelle with its function?

Accepted Answer

Peroxisome: Breakdown of hydrogen peroxide $2H_2O_2 \rightarrow 2H_2O + O_2$

Question 5

During the secretory pathway, which sequence correctly traces the movement of a newly synthesized protein destined for export?

Accepted Answer

Rough ER $\rightarrow$ Golgi apparatus $\rightarrow$ secretory vesicle $\rightarrow$ plasma membrane

Question 6

Which process occurs in the Golgi apparatus and is essential for the proper functioning of many secreted proteins?

Accepted Answer

Glycosylation

Question 7

A mutation prevents the formation of lysosomes in a cell. Which cellular process would be most directly affected?

Accepted Answer

Autophagy (recycling of cellular components)

Question 8

Which of the following is NOT a component of the endomembrane system?

Accepted Answer

Mitochondria

Question 9

Which evidence supports the endosymbiosis theory for the origin of mitochondria and chloroplasts?

Accepted Answer

Both organelles contain circular DNA similar to bacterial genomes.

Question 10

Which of the following best explains the value of compartmentalization in eukaryotic cells, using peroxisomes as an example?

Accepted Answer

It isolates potentially harmful reactions, such as the breakdown of $H_2O_2$, protecting the rest of the cell.

Question 11

Which structure is responsible for assembling ribosomal subunits in eukaryotic cells?

Accepted Answer

Nucleolus

Question 12

What is the main difference between free ribosomes and bound ribosomes?

Accepted Answer

Free ribosomes synthesize proteins for the cytosol, while bound ribosomes synthesize proteins for membranes or secretion.

Question 13

Which of the following is a function of the smooth endoplasmic reticulum?

Accepted Answer

Lipid synthesis

Question 14

Which organelle contains hydrolytic enzymes and maintains an acidic pH for digestion?

Accepted Answer

Lysosome

Question 15

Which of the following correctly compares mitochondria and chloroplasts?

Accepted Answer

Mitochondria have two membrane compartments; chloroplasts have three.

Question 16

A cell is observed to have an extensive network of rough ER. What is the most likely function of this cell?

Accepted Answer

Production of large amounts of secreted proteins

Question 17

Which process is most directly associated with the function of chloroplasts?

Accepted Answer

Photosynthesis: $6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2$

Question 18

Which structure provides mechanical support to the nucleus and helps organize chromatin?

Accepted Answer

Nuclear lamina

Question 19

Which of the following is a direct result of the function of the Golgi apparatus?

Accepted Answer

Modification and sorting of proteins for secretion

Question 20

A mutation disrupts the formation of transport vesicles from the Golgi apparatus. Which cellular process would be most affected?

Accepted Answer

Secretion of proteins and lipids

Cell Structure and the Endomembrane System: Study Guide

Study Guide - Practice Questions