Question

In response to seasonal changes in temperature, many organisms must alter the composition of their plasma membranes to maintain the proper degree of fluidity. Which change in the fatty acids of phospholipids would be most effective in maintaining membrane fluidity in a colder environment?

A. an increase in phospholipid fatty acid side chain length and an increase in side chain saturationB. a decrease in phospholipid fatty acid side chain length and an increase in side chain saturationC. a decrease in phospholipid fatty acid side chain length and a decrease in side chain saturationD. an increase in phospholipid fatty acid side chain length and a decrease in side chain saturation

Answer 1

The correct answer is D

Step-by-step explanation:

The cell membrane is essentially composed of the following:

• phospholipids
• cholesterol
• proteins

The phospholipid consists of a hydrophilic phosphate 'head' and the tail is the hydrophobic fatty acid chain.When cellular membranes form,phospholipids collect into two layers in light of these hydrophilic and hydrophobic properties. The phosphate heads in each layer face the fluid or watery condition on either side, and the tails conceal away from the water between the layers of heads, since they are hydrophobic.

There are 3 main factors that greatly influence the fluidity of the plasma membrane:

• temperature
• cholesterol
• saturated and unsaturated fatty acids