Question

Dramatic temperature changes can induce membrane remodeling involving changing fatty acid structure in membrane phospholipids. This will occur during the transition from winter to spring and vice versa. The purpose of remodeling is to maintain a constant level of membrane fluidity in the cell. Which of the following describes the change you would see in the lipid bilayer of a bear when it comes out of hibernation ?
a. The ratio of long to short fatty acid tails in membrane phospholipids decreases
b. The number of phospholipids in the membrane decreases
c. The ratio of long to short fatty acid tails in the membrane phospholipids increases
d. The number of phospholipids in the membrane increases
e. There is an increase in the saturation state of the fatty acid tails of membrane phospholipids
f. There is a decrease in the saturation state of the fatty acid tails of membrane phospholipids

Answer 1

Answer:

c. The ratio of long to short fatty acid tails in the membrane phospholipids increases

e. There is an increase in the saturation state of the fatty acid tails of membrane phospholipids

Explanation:

In biological lipid membranes, the homeoviscosity refers to the process by which the membrane 'adapts' its lipid composition to maintain a proper fluidity. It is well known that the membrane's fluidity increases with increasing temperatures. In this regard, it is important to have into account two points. First, the length of the fatty acid tail alters the membrane's fluidity: shorter fatty acid tails increase fluidity, while longer fatty acid tails decrease it (because shorter tails establish fewer molecular interactions between fatty acids tails). Second, the degree of saturation (i.e., the number of bonds between the carbon atoms) of fatty acids tails also affects homeoviscosity. A higher saturated fatty acid content decreases the membrane's fluidity because saturated tails are arranged in order to maximize molecular interactions between fatty acids tails.