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TestMaster MCQs

Cell Membrane & Transport Questions

Home Science Cell Membrane & Transport
Q. The cell membrane is primarily composed of:
Cellulose strands
Phospholipid bilayer
Chitin
Protein monolayer

Explanation:

The membrane is a phospholipid bilayer with embedded proteins.

Q. The heads of phospholipids are:
Hydrophobic
Neutral
Charged positive
Hydrophilic

Explanation:

Phospholipid heads are hydrophilic (water-loving) and face outward; tails are hydrophobic.

Q. The tails of phospholipids are:
Neutral
Charged
Hydrophobic
Hydrophilic

Explanation:

Phospholipid tails are hydrophobic and face inward, away from water.

Q. Simple diffusion is a process that:
Moves molecules from high to low concentration without energy
Requires ATP
Moves molecules against concentration gradient
Requires transport proteins

Explanation:

Simple diffusion is passive movement of molecules from high to low concentration without energy.

Q. Osmosis is the movement of:
Ions using ATP
Solutes across a membrane
Proteins across a membrane
Water across a semipermeable membrane

Explanation:

Osmosis is the diffusion of water across a semipermeable membrane.

Q. Facilitated diffusion differs from simple diffusion because it:
Moves only water
Is always active
Uses membrane proteins but requires no energy
Requires ATP

Explanation:

Facilitated diffusion uses membrane proteins but is still passive (no ATP required).

Q. Active transport differs from passive transport because it:
Only works for water
Requires energy to move against gradient
Requires no energy
Only uses diffusion

Explanation:

Active transport requires energy (ATP) to move molecules against their concentration gradient.

Q. The sodium-potassium pump moves:
3 K+ out and 2 Na+ in
3 Na+ out and 2 K+ in
Equal Na+ and K+
Only Na+ into the cell

Explanation:

The Na+/K+ pump moves 3 Na+ out and 2 K+ into the cell using ATP.

Q. The sodium-potassium pump uses how many ATP per cycle?
2 ATP
1 ATP
None
3 ATP

Explanation:

The Na+/K+ ATPase uses 1 ATP per cycle (moving 3 Na+ out and 2 K+ in).

Q. Endocytosis is the process by which cells:
Produce ATP
Release material out of the cell
Divide into two cells
Engulf material into the cell

Explanation:

Endocytosis takes material into the cell by engulfing it in a vesicle.

Q. Phagocytosis is a type of endocytosis that involves:
Producing ATP
Engulfing large particles
Engulfing fluids
Releasing waste

Explanation:

Phagocytosis is 'cell eating' — engulfing large particles like bacteria.

Q. Pinocytosis is a type of endocytosis that involves:
Releasing waste
Producing ATP
Engulfing fluids
Engulfing large particles

Explanation:

Pinocytosis is 'cell drinking' — engulfing fluids and dissolved substances.

Q. Exocytosis is the process by which cells:
Divide into two cells
Take material into the cell
Release material out of the cell
Digest bacteria

Explanation:

Exocytosis releases materials out of the cell via vesicles.

Q. Cholesterol in the cell membrane functions to:
Regulate membrane fluidity
Synthesize proteins
Increase permeability to all substances
Produce ATP

Explanation:

Cholesterol modulates membrane fluidity — decreasing it at high temperatures and increasing it at low temperatures.

Q. A hypertonic solution causes a cell to:
Divide
Shrink (crenate)
Swell (lyse)
Remain unchanged

Explanation:

In a hypertonic solution, water leaves the cell, causing it to shrink (crenate).

Q. A hypotonic solution causes a cell to:
Divide
Swell (lyse)
Shrink
Remain unchanged

Explanation:

In a hypotonic solution, water enters the cell, causing it to swell and possibly lyse.

Q. An isotonic solution causes a cell to:
Shrink
Swell
Remain unchanged
Divide

Explanation:

In an isotonic solution, there is no net water movement, so the cell remains unchanged.

Q. Aquaporins are channel proteins that:
Transport proteins
Produce ATP
Transport sodium
Transport water

Explanation:

Aquaporins allow rapid water transport across cell membranes.

Q. Carrier proteins differ from channel proteins because carrier proteins:
Never use ATP
Only transport water
Undergo conformational changes during transport
Are always passive

Explanation:

Carrier proteins undergo conformational changes to transport solutes; channels simply open a pore.

Q. Receptor-mediated endocytosis is:
Non-selective fluid uptake
Bulk engulfment of particles
Selective uptake via membrane receptors
Release of materials

Explanation:

Receptor-mediated endocytosis uses membrane receptors to target specific molecules (e.g., LDL uptake).

Q. The glycocalyx is:
A layer of phospholipids
A protein pump
A lipid transport protein
The carbohydrate-rich coat on the cell surface

Explanation:

The glycocalyx is the carbohydrate-rich outer coating of the plasma membrane, involved in recognition and adhesion.

Q. Integral membrane proteins are:
Found only in plant cells
Attached only to the membrane surface
Found only in the nucleus
Embedded within the phospholipid bilayer

Explanation:

Integral proteins are embedded within the phospholipid bilayer — some span the entire membrane.

Q. Peripheral membrane proteins are:
Embedded in the bilayer
Found in the nucleus
Part of the cytoskeleton
Attached to the membrane surface

Explanation:

Peripheral proteins attach to the outer or inner surface of the membrane without embedding in the bilayer.

Q. Which is a function of membrane proteins?
Synthesize ATP only
Store water
Produce DNA
Act as receptors and channels

Explanation:

Membrane proteins act as receptors, channels, enzymes, and structural anchors.

Q. Glycoproteins on the cell membrane are involved in:
DNA replication
Photosynthesis
Cell-cell recognition and immunity
ATP synthesis

Explanation:

Glycoproteins mediate cell-cell recognition, adhesion, and immune responses.

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