Keystone Biology: Cell Processes/Transport Questions and Answers

Question 1

A scientist places a sample of red blood cells into a beaker containing a solution with a much higher salt concentration than the cells' cytoplasm. Which of the following outcomes is most likely?

Accepted Answer

The red blood cells will shrivel because water will move out of the cells.

Answer

The red blood cells will swell and burst because water will move into the cells.

Answer

The red blood cells will remain unchanged because the cell membrane is impermeable to water.

Answer

The red blood cells will actively pump salt out to equalize the concentration.

Question 2

Which of the following cellular processes requires the direct expenditure of energy in the form of ATP to move substances against their concentration gradient?

Accepted Answer

Active transport

Answer

Facilitated diffusion

Answer

Osmosis

Answer

Simple diffusion

Question 3

A single-celled freshwater organism, like a Paramecium, lives in a hypotonic environment. To maintain homeostasis, it must constantly pump out excess water that enters the cell. Which organelle is primarily responsible for this function?

Accepted Answer

Contractile vacuole

Answer

Mitochondrion

Answer

Ribosome

Answer

Nucleus

Question 4

Some large molecules, like hormones or waste products, are packaged into vesicles and transported out of the cell when the vesicle fuses with the plasma membrane. What is this process called?

Accepted Answer

Exocytosis

Answer

Endocytosis

Answer

Phagocytosis

Answer

Pinocytosis

Question 5

Both facilitated diffusion and active transport are processes that move substances across the cell membrane. What is a key characteristic they have in common?

Accepted Answer

They both utilize specific transport proteins embedded in the membrane.

Answer

They both move substances against a concentration gradient.

Answer

They both require the cell to expend energy (ATP).

Answer

They both only transport water molecules across the membrane.

Question 6

A cell's plasma membrane is described as selectively permeable. Which statement BEST explains this property?

Accepted Answer

The membrane allows certain substances to pass through while preventing the passage of others.

Answer

The membrane allows all substances to pass through freely, but only at certain times.

Answer

The membrane allows only water to enter the cell and nothing to leave.

Answer

The membrane blocks all materials from entering or leaving the cell, acting as a rigid wall.