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

Question 1

What is the primary function of glycoproteins in the cell surface membrane?

Accepted Answer

To act as cell-surface receptors for hormones and other signaling molecules

Question 2

How does active transport differ from facilitated diffusion in terms of protein function and energy usage?

Accepted Answer

Active transport requires ATP to change the shape of carrier proteins to move substances against a gradient

Question 3

What happens to the rate of facilitated diffusion as the concentration of a substrate increases, assuming the number of transport proteins remains constant?

Accepted Answer

The rate increases until all transport proteins are saturated, then plateaus

Question 4

Which of the following are true regarding the structure of intrinsic (integral) proteins in the cell membrane?

Answer

They span the entire width of the phospholipid bilayer

Answer

They are only found on the inner surface of the membrane

Answer

They often contain hydrophobic amino acids in the regions spanning the fatty acid tails

Answer

They are held in place solely by covalent bonds to the phospholipids

Question 5

Why is the cell membrane described as a 'fluid-mosaic' model?

Answer

Because the phospholipids and proteins can move laterally within the layer

Answer

Because the membrane is composed of a rigid, static lattice of proteins

Answer

Because the proteins are scattered throughout the bilayer like tiles in a mosaic

Answer

Because the membrane is entirely composed of fluid-like carbohydrates