Proteins in membranes

Question 1

What are intrinsic proteins? And what are the two types?

Answer 1

Proteins that are transmembrane and are embedded through both layers of the membrane

channel and carrier

Question 2

How are they kept in place?

Answer 2

they have amino acids with hydrophobic R-groups on their external surfaces, which interact the hydrophobic core of the membrane

Question 3

What are the functions of channel proteins?

Answer 3

provide a hydrophillic channel that allows the passive movement of polar molecules and ions down concentration gradient through membranes

Question 4

What are the functions of carrier proteins?

Answer 4

important role in passive transport and active transport into cells

this involves often changing the shape of the protein changing

Question 5

What are extrinsic proteins?

Answer 5

present in one side of the bilayer

they can be present in either layer and some move between layers

Question 6

What keeps extrinsic proteins in place?

Answer 6

they normally have hydrophilic R-groups on their outer surface and interact weith polar head of the phospholipids or with intrinsic proteins