Take this Quiz: A-Level Biology: Transport Across Membranes | Zestly

Question 1

In the fluid-mosaic model of the cell membrane, what is the primary structural role of cholesterol molecules embedded within the phospholipid bilayer?

Accepted Answer

They regulate membrane fluidity by restricting lateral movement of phospholipids

Question 2

Which of the following statements accurately describe the movement of substances across a cell membrane via facilitated diffusion?

Accepted Answer

It requires specific transmembrane proteins to allow polar or charged molecules to pass

Question 3

A plant cell is placed in a solution with a water potential significantly higher than that of the cell's cytoplasm. What will be the observable state of the cell?

Accepted Answer

The cell will become turgid as water enters the vacuole and pushes against the cell wall

Question 4

During the sodium-glucose co-transport in the ileum, which of the following processes directly drive the movement of glucose into the epithelial cell?

Answer

The direct hydrolysis of ATP by the glucose carrier protein

Answer

The movement of sodium ions down their concentration gradient into the cell

Answer

The passive diffusion of glucose through the phospholipid bilayer

Answer

The maintenance of a low intracellular sodium concentration by the sodium-potassium pump

Question 5

Which factors increase the rate of simple diffusion across a phospholipid bilayer?

Answer

Increased surface area of the membrane

Answer

Increased concentration gradient across the membrane

Answer

Increased thickness of the membrane

Answer

Increased lipid solubility of the diffusing molecule