B2.1 Membranes and membrane transport Questionbank

To pump water into lysosomes using ATP

To form vesicles during exocytosis

To allow rapid diffusion of water molecules through the membrane

To hydrolyze solutes in the extracellular space

Floating in the middle of the membrane’s hydrophobic core

Spanning across both sides of the membrane

Loosely attached to one surface of the membrane, often via other proteins

Synthesizing DNA on the outer surface of the nucleus

The pressure inside the cell

The number of solutes bound to it

A conformational change in response to signals or voltage

The type of phospholipid it is attached to

The presence of cholesterol

The hydrophilic phosphate groups

The tightly packed glycoproteins

The hydrophobic fatty acid chains in the core

Hydrophobic interactions minimize exposure of fatty acid tails to water

Hydrogen bonds link adjacent phospholipids into sheets

Their polar heads repel each other, forcing tails together

Water molecules actively pull phosphate groups into alignment

They form rigid tunnels made of triglycerides

They contain a hydrophilic pore that selectively allows certain ions to pass

They undergo phosphorylation to bind ATP

Their hydrophobic interior interacts with water

They are fully embedded in both membrane layers

They have a fixed pore size that allows only small polar molecules through

Their interior shape and chemical environment match specific transported substances

They are permanently open and allow all solutes to pass through

It passively allows sodium and potassium ions to diffuse down their concentration gradients to establish an equilibrium.

It actively transports sodium and potassium ions using ATP, creating an electrochemical gradient critical for membrane potential.

It transports sodium ions into the cell and potassium ions out of the cell without energy expenditure.

It creates a uniform ion distribution inside and outside the cell, thereby preventing depolarization events.

Triglyceride layer

Lipid monolayer

Phospholipid bilayer

Steroid ring structure

Oxygen (O₂)

Carbon dioxide (CO₂)

Sodium ions (Na⁺)

Small non-polar molecules