Phospholipids and Lipid Bilayer Membranes

Question 1

What are membrane lipids?

Answer 1

phospholipids derived from diacylglycerol phosphate (DG-P)

Question 2

What molecules are sometimes attached to the phosphate group of membrane lipids?

Answer 2

more polar molecules:
choline, ethanolamine, inositol

Question 3

What are the most common phospholipids in eukaryotic cells?

Answer 3

phosphatidylcholine
phosphatidylethanolamine

Question 4

What other component besides membrane lipids is phosphatidylcholine a part of?

Answer 4

lung surfactant

Question 5

What other component besides membrane lipids if phosphatidylethanolamine a part of?

Answer 5

signal transmission across cell membrane

Question 6

How do phospholipids minimize their interactions with water?

Answer 6

forming a lipid bilayer

Question 7

What is the lipid bilayer stabilized by once it is formed?

Answer 7

van der Waal interactions between the long tails

Question 8

What tends to increase membrane fluidity?

Answer 8

unsaturated phospholipid fatty acids
decreasing the length of fatty acid tails

Question 9

What is cholesterol and why is it important for membrane fluidity?

Answer 9

steroid known as membrane antifreeze that keeps membrane fluidity at an optimum level
at low temperatures, it increases membrane fluidity
at high temperatures it reduces membrane fluidity

Question 10

What is the main function of the lipid bilayer?

Answer 10

barrier surrounding the cell that regulates what comes in and out of the cell and transmits extracellular signals to the interior of the cell