Question 1

Which of the following best explains why cells are generally small in size?

Accepted Answer

Smaller cells have a higher surface area-to-volume ratio, which facilitates efficient exchange of materials with their environment.

Question 2

A scientist is using a microscope to observe the detailed structure of a mitochondrion. Which type of microscope should she use, and why?

Accepted Answer

Transmission electron microscope, because it provides high resolution images of internal cell structures.

Question 3

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

Accepted Answer

Mitochondrion

Question 4

Which of the following statements about the fluid mosaic model of the plasma membrane is correct?

Accepted Answer

The membrane is composed of a phospholipid bilayer with proteins embedded throughout, allowing lateral movement of both lipids and proteins.

Question 5

A red blood cell is placed in a hypotonic solution. What will most likely happen to the cell, and why?

Accepted Answer

It will swell and may burst, because water enters the cell by osmosis.

Question 6

Which of the following best describes the function of ribosomes?

Accepted Answer

They synthesize proteins by translating messenger RNA.

Question 7

Which of the following is evidence supporting the endosymbiotic theory for the origin of mitochondria and chloroplasts?

Accepted Answer

Both organelles contain their own circular DNA similar to bacterial DNA.

Question 8

Which of the following molecules would most easily diffuse through a pure phospholipid bilayer without the help of a transport protein?

Accepted Answer

Oxygen ($$O_2)$$

Question 9

A plant cell is placed in a hypertonic solution. What is the most likely outcome, and what is the process called?

Accepted Answer

The cell will lose water and undergo plasmolysis.

Question 10

Which of the following best explains why animal cells prefer isotonic environments, while non-woody plant cells prefer hypotonic environments?

Accepted Answer

Animal cells lack a cell wall and can burst in hypotonic solutions, while plant cells rely on turgor pressure for structural support.

Question 11

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

Accepted Answer

It helps maintain membrane fluidity at different temperatures by preventing tight packing of phospholipids.

Question 12

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

Accepted Answer

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

Question 13

A white blood cell engulfs a bacterium by surrounding it with its plasma membrane, forming a vesicle. What is this process called?

Accepted Answer

Phagocytosis

Question 14

Which of the following statements about facilitated diffusion is correct?

Accepted Answer

It requires a transport protein but does not require energy input from the cell.

Question 15

Which of the following best describes the difference between integral and peripheral membrane proteins?

Accepted Answer

Integral proteins span the membrane and can function as transport proteins, while peripheral proteins are attached to the membrane surface and do not span the bilayer.

Question 16

A cell uses ATP to pump sodium ions ($$Na^+) $$out of the cell and potassium ions ($$K^+) $$into the cell against their concentration gradients. Which type of transport is this, and what is the name of the protein involved?

Accepted Answer

Active transport; sodium-potassium pump

Question 17

Which of the following best explains why mitochondria and chloroplasts are not considered part of the endomembrane system?

Accepted Answer

They have a double membrane and their own DNA, suggesting a different evolutionary origin.

Question 18

Which of the following best describes the function of microtubules in the cytoskeleton?

Accepted Answer

They provide tracks for motor proteins to move organelles and vesicles within the cell.

Question 19

Which of the following scenarios best illustrates the interaction between two organelles to accomplish a cellular function?

Accepted Answer

A protein synthesized by a ribosome on the rough endoplasmic reticulum is packaged into a vesicle and sent to the Golgi apparatus for modification.

The Cell and Membrane Transport: Structure, Function, and Dynamics

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