Feb. 27th - Temp. Tolerance Continued

Question 1

membrane fluidity depends on

Answer 1

temperature and membrane composition

Question 2

Membrane phospholipid tail composition

Answer 2

• unsaturated fatty acids (C=C) increase fluidity because bends in fatty acids prevent them from packing close together
• shorter fatty acids (fewer Cs) tend to increase membrane fluidity b/c fewer intermolecular interactions (vanderwalls) btw fatty acids = weaker packing together

Question 3

membrane phospholipid head group composition
(glycerol + phosphate + additional polar group)

Answer 3

• smaller head group = “conical” shape b/c FA tail spreads out… this tends to increase fluidity. ex. PE

-larger head group = “cylindrical” shape b/c tails closer together … decreases fluidity. ex. PC

Question 4

membrane cholesterol composition

Answer 4

rigid structure due to 4 C rings

• warm… helps decrease fluidity due to rigidity

-cool… helps increase fluidity by preventing phospholipids from packing together too closely
(ring structure = barrier btw phospholipids)