AP Biology Practice Quiz: Membrane Transport

Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026

Test your understanding with short quizzes. This quiz has 15 questions to check your progress.

Question 1 of 15

Which of the following transport mechanisms is defined by the net movement of molecules from an area of high concentration to an area of low concentration without the use of metabolic energy?

A)Active transportB)EndocytosisC)Passive transportD)Exocytosis

All Questions (15)

Which of the following transport mechanisms is defined by the net movement of molecules from an area of high concentration to an area of low concentration without the use of metabolic energy?

A) Active transport

B) Endocytosis

C) Passive transport

D) Exocytosis

Correct Answer: C

According to the provided content, 'Passive transport is the net movement of molecules from high to low concentration without requiring metabolic energy.' The other options all require an input of energy.

A cell needs to move a substance from an external environment with a low solute concentration to its cytoplasm, which has a high solute concentration. This process requires a direct input of energy. What is this mechanism called?

A) Active transport

B) Passive transport

C) Osmosis

D) Facilitated diffusion

Correct Answer: A

The content states that 'Active transport requires a direct input of energy to move molecules, often from a region of low concentration to one of high concentration.' This scenario perfectly matches the definition.

The ability of a plasma membrane to allow certain substances to pass through while preventing others is known as selective permeability. According to the text, what does this property directly enable?

A) The direct expenditure of metabolic energy.

B) The formation of concentration gradients.

C) The engulfing of large molecules by vesicles.

D) The fusion of vesicles with the membrane.

Correct Answer: B

The provided text explicitly states, 'The selective permeability of membranes enables the formation of concentration gradients of solutes.'

A cell needs to secrete a large protein-based hormone into the bloodstream. Which of the following mechanisms would be used for this process of bulk export?

A) Endocytosis

B) Exocytosis

C) Passive transport

D) Active transport pump

Correct Answer: B

The content describes exocytosis as a process that requires energy to move large substances out of cells by having vesicles fuse with the plasma membrane.

What is a fundamental difference between active transport and passive transport?

A) Active transport moves substances along the concentration gradient, while passive transport moves them against it.

B) Active transport requires metabolic energy, while passive transport does not.

C) Passive transport involves vesicles, while active transport uses protein channels.

D) Only passive transport is used to maintain water balance.

Correct Answer: B

The core distinction highlighted in the text is that 'Passive transport... [occurs] without requiring metabolic energy,' whereas 'Active transport requires a direct input of energy.'

The process of a cell engulfing a large particle, such as a bacterium, by forming a vesicle around it is an example of:

A) Exocytosis

B) Passive diffusion

C) An active transport pump

D) Endocytosis

Correct Answer: D

The text states that 'Endocytosis... require[s] energy to move large substances into... cells by forming vesicles that engulf material.'

Which of the following statements accurately describes a shared characteristic of endocytosis and exocytosis?

A) Both processes move substances down their concentration gradient.

B) Both are forms of passive transport for large molecules.

C) Both processes require an expenditure of cellular energy.

D) Both mechanisms are primarily used for transporting small ions and water.

Correct Answer: C

The provided content explicitly states, 'Endocytosis and exocytosis require energy to move large substances into and out of cells.'

A plant root cell has a much higher concentration of mineral ions than the surrounding soil. To acquire even more minerals, the cell must use a specific transport mechanism. This mechanism is most likely:

A) Passive transport, as the minerals will naturally flow into the cell.

B) Active transport, to pump ions against their concentration gradient.

C) Exocytosis, to release vesicles that capture the minerals.

D) Endocytosis, because the soil is a large substance.

Correct Answer: B

Moving minerals from a low concentration (soil) to a high concentration (cell) is moving against the concentration gradient. The text defines this process as active transport, which requires energy.

The maintenance of solute and water balance is a critical function for all organisms. The movement of water across a selectively permeable membrane down its concentration gradient is a form of which transport type?

A) Active transport

B) Exocytosis

C) Endocytosis

D) Passive transport

Correct Answer: D

The movement of any substance from high to low concentration without energy is passive transport. Osmosis, the movement of water, is a specific type of passive transport.

The driving force for all forms of passive transport is the:

A) Input of metabolic energy.

B) Formation of vesicles.

C) Existence of a concentration gradient.

D) Fusion of vesicles with the plasma membrane.

Correct Answer: C

Passive transport is defined as the net movement of molecules from high to low concentration. This difference in concentration, or concentration gradient, is what drives the movement.

How are large molecules, such as antibodies, transported across the plasma membrane?

A) Through simple diffusion directly across the lipid bilayer.

B) Via active transport pumps specific to antibodies.

C) Through mechanisms like endocytosis and exocytosis.

D) By passive transport through protein channels.

Correct Answer: C

The content specifies that organisms 'transport large molecules across the plasma membrane' using mechanisms like endocytosis and exocytosis which 'move large substances into and out of cells.'

A cell first uses energy to accumulate a high concentration of a specific solute. It then uses this concentration gradient to drive the transport of another substance across the membrane without a further direct input of energy for the second substance. The initial accumulation of the solute is an example of:

A) Passive transport

B) Active transport

C) Exocytosis

D) Endocytosis

Correct Answer: B

The first step described is using energy to create a high concentration of a solute, moving it from low to high concentration. This is the definition of active transport, which establishes the concentration gradient.

Which of the following processes involves the fusion of a vesicle with the plasma membrane to release its contents to the extracellular environment?

A) Passive transport

B) Active transport

C) Endocytosis

D) Exocytosis

Correct Answer: D

The content describes exocytosis as a process that requires energy to move large substances out of cells by having vesicles 'fuse with the plasma membrane.'

A marine organism is hypotonic to its environment, causing it to constantly lose water to the sea. To maintain its internal water and solute balance, it must actively transport ions out of its body. This ion movement is an example of:

A) Passive transport, because it helps maintain balance.

B) Active transport, because it requires energy to move ions against a gradient.

C) Endocytosis, to bring in seawater for processing.

D) Exocytosis, to expel large amounts of water.

Correct Answer: B

To pump ions from a lower internal concentration to a higher external concentration (the sea), the organism must move them against their concentration gradient. This process requires energy and is defined as active transport.

A cell synthesizes a large batch of signaling molecules and packages them into vesicles. To release these molecules all at once, the cell would utilize which energy-dependent process?

A) Passive diffusion

B) An ion pump

C) Exocytosis

D) Endocytosis

Correct Answer: C

The release of large quantities of substances packaged in vesicles is the definition of exocytosis. The text confirms this is an energy-requiring process used to move large substances out of the cell.