Question 1

Which of the following statements best explains why mitochondria and chloroplasts are considered to have originated from endosymbiotic events?

Accepted Answer

They contain their own circular DNA and ribosomes, similar to prokaryotes.

Question 2

A cell is observed to have a large central vacuole, chloroplasts, and a cell wall composed mainly of cellulose. Which type of cell is this most likely to be?

Accepted Answer

Plant cell

Question 3

Which organelle is primarily responsible for the synthesis of steroid hormones in animal cells?

Accepted Answer

Smooth endoplasmic reticulum

Question 4

A mutation disrupts the function of the nucleolus in a eukaryotic cell. Which process would be most directly affected?

Accepted Answer

rRNA synthesis and ribosome assembly

Question 5

Which of the following best represents the main function of lysosomes in animal cells?

Accepted Answer

Intracellular digestion of macromolecules

Question 6

A scientist isolates a cell with the following features: a nucleoid region, circular DNA, and thylakoid membranes. What is the most likely identity of this cell?

Accepted Answer

Cyanobacterium

Question 7

Which of the following equations correctly represents the process of cellular respiration in mitochondria?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$ + 6O_2 \rightarrow 6CO_2 + 6H_2O + ATP}$$

Question 8

Which structure is responsible for sorting, modifying, and packaging proteins for secretion or delivery to other organelles?

Accepted Answer

Golgi apparatus

Question 9

A patient has a genetic disorder that results in defective catalase enzyme. Which organelle's function is most directly impaired?

Accepted Answer

Peroxisome

Question 10

Which of the following is a key difference between prokaryotic and eukaryotic cells?

Accepted Answer

Location of genetic material

Question 11

Which cytoskeletal element is primarily responsible for the movement of chromosomes during mitosis in animal cells?

Accepted Answer

Microtubules

Question 12

Which of the following best describes the function of plasmodesmata in plant cells?

Accepted Answer

They are channels that allow transport of water and small molecules between cells.

Question 13

A cell is exposed to a toxin that inhibits glycosylation of proteins. Which organelle is most likely to be directly affected?

Accepted Answer

Golgi apparatus

Question 14

Which of the following is NOT a function of the smooth endoplasmic reticulum?

Accepted Answer

Synthesis of ribosomal RNA

Question 15

Which of the following best describes the composition of the plasma membrane?

Accepted Answer

A double layer of phospholipids with embedded proteins

Question 16

Which of the following cell junctions in animal cells prevents the leakage of extracellular fluid between neighboring cells?

Accepted Answer

Tight junctions

Question 17

A muscle cell is unable to contract due to a failure in calcium ion storage and release. Which organelle is most likely malfunctioning?

Accepted Answer

Smooth endoplasmic reticulum

Question 18

Which of the following best describes the role of the extracellular matrix (ECM) in animal cells?

Accepted Answer

It provides structural support and mediates cell signaling.

Question 19

Which of the following is a function of glyoxysomes in plant seeds?

Accepted Answer

Conversion of fatty acids to sugars during germination

Question 20

Which of the following best explains why lysosomal enzymes are not active in the cytosol if a lysosome ruptures?

Accepted Answer

The cytosol is neutral, and lysosomal enzymes require an acidic pH.

Cell Structure and Function: A Comprehensive Guide for Molecular Biology

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