# 10.5: Problems

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10.1 Questions

1) Explain why some lipid classes are membrane-forming and some are not. Give examples that support your logic.

2) a. Using the images of fatty acids below, write the symbolic name (N:N) for each.

For the following use FA 1, 2, 3, or 4, some may have more than one answer.

b. Which fatty acid melts at the highest temperature?

c. Which fatty acid is a w-3 fatty acid and is essential for human growth and development?

d. Which fatty acid, if found in a membrane bilayer, would increase membrane fluidity?

e. Which fatty acid is the most unlikely to be found in nature, and why?

3) For the following questions, use the interactive micelle from Section 10.1:

a. When looking at the micelle in “Ball and Stick” form, do you think the core (center of the micelle) could be accessible to water molecules? Explain.

b. Examine the micelle under Style -> Surface Type -> Molecular Surface. Did your answer from part a change? Do there appear to be any solvent-accessible regions that water could use to enter the core?

c. Finally, examine the micelle under Style -> Surface Type -> Solvent Accessible. Does this view change your answer to a.? Can you think of any medical or research applications in which a micelle could be useful given what you have found about its solvent accessibility?

4)Using the figure below, hypothesize what type of lipid could be represented by the geometrical shapes in the membrane. Why are the different shapes necessary for membrane formation? Could a membrane be formed with only one shaped lipid? If so, what, and explain why.

5) A cell membrane has the ability to remodel in response to stress in order to maintain membrane integrity. In the situations below, how could the membrane be remodeled to promote an intact structure? (I.e. what types of lipids could be added or removed to maintain a functional membrane?

a. Increase in temperature

b. Decrease in temperature

6)

For each lipid below, name the type of lipid (membrane lipid, triacylglycerol, storage lipid, sphingolipid, wax, sterol, membrane glycerolipid, none of these), if it could be found in a membrane, and if it is a fatty acid or isoprenoid derived.

This page titled 10.5: Problems is shared under a not declared license and was authored, remixed, and/or curated by Henry Jakubowski and Patricia Flatt.