Cell Structure: Facilitated Diffusion

Question 1

Which substances cannot easily diffuse through the hydrophobic phospholipid bilayer’s core?

Answer 1

Hydrophilic substances

Question 2

What do larger hydrophilic substances diffuse via?

Answer 2

Protein molecules

Question 3

Which proteins are involved in facilitated diffusion?

Answer 3

Intrinsic- Channel proteins and carrier proteins

Question 4

Describe how a carrier protein can move a hydrophilic molecule across a membrane.

Answer 4

-The specific chemical being transported, binds to the carrier protein’s binding site.
-This binding, then causes the tertiary structure of the protein molecule to change.
-This change in structure, brings the chemical, across the membrane and the chemical is then released.

Question 5

What is the changing of tertiary structure of a carrier protein, also known as?

Answer 5

Allostery

Question 6

What do protein channels have in their centres?

Answer 6

A channel lined with hydrophilic amino acids and water.

Question 7

What does the protein channel’s structure allow to pass through the plasma membrane?

Answer 7

Hydrophilic substances.

Question 8

Are protein channels selective to the chemical they allow to pass through?

Answer 8

Yes

Question 9

Is each protein channel specific to a certain chemical?

Answer 9

Yes

Question 10

Describe what is meant by a Ligand-gated protein (/ion) channel?

Answer 10

A protein channel that only opens in response to a specific trigger such as a chemical binding to the protein.

Question 11

Give an example of a Ligand?

Answer 11

Neurotransmitters

Question 12

Is facilitated diffusion passive or active?

Answer 12

Passive