Chapter 5.1

Question 1

Describe the general characteristics of phospholipids

Answer 1

• it contains a:
• > phosphate molecule and an alcohol that comprise the polar head group
• > also a hydrophobic fatty acid tail
• the non polar part and polar part are joined by a phosphodiester linkage

Question 2

What is glycerol? Note that glycerol is a phospholipid

Answer 2

• a three carbon alcohol

- can form phosphoglycerides, glycerophospholipids and sphingolipids

Question 3

Are all sphingolipids phospolipids

Answer 3

-no they are not

Question 4

Describe the difference between saturated fatty acids and unsaturated fatty acids

Answer 4

Saturated

• > only single bonds
• > carbon bond is saturated when it is bound to four other atoms with no pi bonds
• > have greater van der Waals forces and a more stable structure than unsaturated fatty acids

Unsaturated

• > includes one or more double bonds
• > double bonds introduce kinks into the structure
• > the kinks make it difficult to stack and solidify these structures
• tend to be liquid at room temp

Question 5

Describe the general structure of glycerophospholipids. Specifically focus on the polar head group

Answer 5

• glycerol backbone bonded by two ester linkages to two fatty acids
• also a phosphodiester linkage to a highly polar head group

-note the polar head group can be positively charged or negatively charged or neutral

Question 6

What are the function of the membrane surface properties of glycerophospholipids

Answer 6

• they are used for cell recognition, cell signalling and binding
• the function varies depending on the length of the fatty acid chains

Question 7

Describe the general structure of sphingolipids

Answer 7

• sphingosine backbone
• > as opposed to glycerol backbone glycerophospholipids
• > also have long-chain nonpolar fatty acid tails and a polar head group

Question 8

How does a sphingolipid become a phospholipid? How does it not

Answer 8

• if it contains a phosphodiester linkage
• > then the sphingolipid becomes a phospholipid
• if it contains a glycosidic linkage instead of a phosphodiester linkage
• > then the sphingolipid becomes a glycolipid

Question 9

Describe the general structure of waxes

Answer 9

• esters
• > of long chain fatty acids with long chain alcohols
• form solids at room temperature
• > provide protection for both plants and animals

Question 10

What are waxes used in for plants and animals

Answer 10

Plants

• > waxes are secreted as a surface coating to prevent excessive evaporation
• > protects against parasites

Animals
->waxes are secreted to prevent dehydration

Question 11

Is phosphatidylcholine and phosphatidylethanolamine a glycerophospholipid

Answer 11

• yes
• phosphatidylcholine has choline as a head group
• phosphatidylethanilamine has ethanolamine as a head group