Question 1

Which of the following statements best explains the endosymbiosis theory for the origin of mitochondria and chloroplasts?

Accepted Answer

Mitochondria and chloroplasts originated as free-living prokaryotes that were engulfed by ancestral eukaryotic cells, forming a symbiotic relationship.

Question 2

A scientist observes a cell with a nucleoid region, circular DNA, and no membrane-bound organelles. Which type of cell is being observed?

Accepted Answer

Prokaryotic cell

Question 3

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

Accepted Answer

Modifying, sorting, and packaging proteins and lipids for secretion or delivery to other organelles

Question 4

A red blood cell is placed in a solution and begins to shrink. Which of the following best describes the tonicity of the solution relative to the cell?

Accepted Answer

Hypertonic

Question 5

Which of the following equations correctly represents the process of osmosis across a semipermeable membrane?

Accepted Answer

$$ J = -P (C_2$ - C_1$) $$

Question 6

Which of the following best describes the role of cholesterol in the plasma membrane of animal cells?

Accepted Answer

Cholesterol stabilizes membrane fluidity by preventing tight packing of phospholipids at low temperatures and restricting movement at high temperatures.

Question 7

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

Accepted Answer

Detoxification of hydrogen peroxide by converting it to water

Question 8

A mutation prevents the formation of integrins in an animal cell. Which cellular structure or function would be most directly affected?

Accepted Answer

Attachment of the cell to the extracellular matrix

Question 9

Which of the following best describes the difference between channel proteins and carrier proteins in facilitated diffusion?

Accepted Answer

Channel proteins form hydrophilic tunnels for specific molecules or ions to pass, while carrier proteins undergo conformational changes to move substances across the membrane.

Question 10

Which of the following best explains why plant cells do not burst when placed in a hypotonic solution?

Accepted Answer

The rigid cell wall provides structural support and prevents excessive expansion.

Question 11

Which of the following is a correct description of the sodium-potassium pump?

Accepted Answer

It moves 3 sodium ions out of the cell and 2 potassium ions into the cell using ATP.

Question 12

Which of the following best describes the interaction between actin filaments and myosin in muscle contraction?

Accepted Answer

Myosin filaments slide past actin filaments, shortening the muscle cell.

Question 13

A cell is observed to engulf a bacterium by extending its plasma membrane around the particle and forming a vesicle. Which process is being described?

Accepted Answer

Phagocytosis

Question 14

Which of the following best describes the function of the nuclear pore complex?

Accepted Answer

It regulates the movement of molecules between the nucleus and cytoplasm.

Question 15

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

Accepted Answer

Eukaryotic cells have a nucleus containing DNA, while prokaryotic cells have DNA in a nucleoid region.

Question 16

Which of the following best describes the fluid mosaic model of the plasma membrane?

Accepted Answer

A dynamic structure with proteins and lipids able to move laterally within the bilayer.

Question 17

Which of the following is a function of the extracellular matrix (ECM) in animal cells?

Accepted Answer

Facilitating cell-to-cell communication and providing structural support

Question 18

A cell is placed in a solution where water moves into the cell, causing it to swell. Which of the following best describes the solution?

Accepted Answer

Hypotonic

Question 19

Which of the following best describes the function of lysosomes?

Accepted Answer

Digesting macromolecules and recycling cellular components

Question 20

Which of the following best explains why ions such as $$ \mathrm{Na}^+ $$ and $$ \mathrm{K}^+ $$ cannot freely cross the plasma membrane?

Accepted Answer

They are charged and cannot pass through the hydrophobic core of the lipid bilayer without the help of transport proteins.

General Cell Biology Study Guide: Step-by-Step Guidance for Key Concepts

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