Intro to Lipids

Question 1

Lipids are defined primarily by their ___ properties rather than their ___ structure

Answer 1

physical, chemical

Question 2

Define a lipid

Answer 2

All biological molecules that are insoluble in water, soluble in non-polar organic solvents

Question 3

Discuss lipid solubility

Answer 3

Solubility characteristics of lipids are result of hydrocarbon structure

Question 4

What are three major functions of lipids?

Answer 4

Energy storage, structure, and signaling

Question 5

What is a fatty acid?

Answer 5

An unbranched hydrocarbon chain with carboxylic acid at one end

Question 6

Fatty acids tend to have an even or an odd number of carbon atoms?

Answer 6

Contain even number of carbon atoms

Question 7

What is the difference between a saturated and unsaturated fatty acid?

Answer 7

Saturated = no double bonds
Unsaturated = double bonds

Question 8

In an unsaturated fatty acid, double bonds can be either ___ or ___

Answer 8

Cis or Trans

Question 9

What is a triaclglyceride ((general)?

What is a simple TAG?

What is a mixed TAG?

Answer 9

Glycerol backbone and 3 attached fatty acids

TAG with same FA attached at all 3 spots

TAG with different kinds of FAs attached

Question 10

What is a glycolipid

Answer 10

Sphingosine backbone, linked to carbohydrate instead of phosphate head

Question 11

What is a glycerophospholipid?

Answer 11

The lipids that makeup membrane bilayers, polar head (phosphate or alcohol group) and 2 FAs

Question 12

What is a steroid lipid?

Answer 12

These are derived from cholesterol and they include glucocorticoids, mineralocorticoids, androgens, estrogens, progestins

Question 13

How are lipids named using the delta system?

Answer 13

Start with carbonyl carbon in carboxylate group, that’s carbon 1. Number all carbons after that. Any carbons that are part of a double bond are indicated as (Delta sign) #,#,# etc. Where # is the lower of the 2 carbons involved in the bond

Question 14

How are lipids named using the omega system?

Answer 14

Start at the tail end of the lipid. The last carbon is carbon 1. Number all the carbons in the lipid going toward the carbonyl carbon until you reach a double bond. Stop at the first carbon in that double bond. Name the lipid with (omega symbol) - # of first carbon in double bond.

Question 15

What is the lipidome?

What is lipidomics?

Answer 15

Totality of lipids in cell, subdivided into membrane and mediator lipodomes

Lipidomics = study of lipids, similar to genomics, proteomics, etc.

Question 16

What structural feature to cis double bonds introduce into FAs?

Answer 16

A kink / bend

Question 17

What 3 types of lipids make up most of the cell membrane?

Answer 17

Phospholipids
Glycolipids
Cholesterol

Question 18

Do phospholipids always have a glycerol backbone?

Answer 18

No, they can also have a sphingosine backbone (Sphingomyelin)

Question 19

What is ALWAYS the backbone of glycolipids?

Answer 19

Sphingosine

Question 20

Glycolipids are synonymous with ___?

Answer 20

Sphingolipids

Question 21

Describe the structure of a glycerophospholipid?

Answer 21

Amino alcohol –> phosphate –> glycerol –> 2 FAs

Question 22

Describe the structure of sphingomyelin

Answer 22

Amino alcohol –> phosphate group –> sphingosine –> 1 FA

Question 23

Define the term amphipathic and how it relates to lipids.

Answer 23

Amphipathic refers to compounds that contain both a polar and non-polar region. Membrane lipids (phospholipids) and glycolipids display this characteristic.

Question 24

What other molecules are derived from cholesterol?

Answer 24

Vitamin D
Bile Salts
Lipid signaling molecules