exam 2

Question 1

MP Group 1

Answer 1

Small nonpolar molecules that pass freely (O2, CO2, N2, steroid hormones)

Question 2

MP Group 2

Answer 2

Small uncharged polar molecules. They cannot pass as freely but a bit can still go through (H2O, ethanol, glycerol)

Question 3

MP Group 3

Answer 3

Large uncharged polar molecules. Very small amount could pass but not much at all. (AAs, glucose, nucleosides).

Question 4

MP Group 4

Answer 4

Ions (any charged molecule or atom) cannot pass. They must use ion channels

Question 5

How are phospholipids synthesized?

Answer 5

Cytoplasmic face of ER by enzymes that use fatty acids. This is why you can’t add genes to them like proteins.

Question 6

Where are membranes assembled?

Answer 6

ER, they have no genetic code and are simply built from amino acid sequences.

Question 7

Are unsaturated lipids more fluid?

Answer 7

Yes. They have double bonds in their fatty acid tails, leading to less tightly packed membranes.

Question 8

Why are sat fats not fluid?

Answer 8

Their fatty acid tails are tightly packed, as they do not have any kinks.

Question 9

Do transporters undergo conformational change?

Answer 9

Yes! They undergo conformational change due to substrate binding and dissociation.

Question 10

What do channels allow to pass?

Answer 10

They allow things to pass based on size and electric charge. No conformational change needed