Lecture 19. Lipids

Question 1

Where are fatty acids stored and sythesised ?

Answer 1

Fatty acids are stored as triacylglycerides in adipocytes and synthesised in the liver

Question 2

What are lipins ?

Answer 2

Proteins with roles in lipid metabolism and disease

Question 3

What is k1

Answer 3

Precursor of most vitamin k in nature and is a steroisomer of phyllquinone

Question 4

What is phylloquinone ?

Answer 4

An electron acceptor in photosynthesis

Question 5

What are the five major classes of steroid hormones ?

Answer 5

1. progestogens
2. glucocorticoids
3. mineralocorticoids
4. androgens
5. estrogens

Question 6

What is cholesterol a precursor to ?

Answer 6

Steroid hormones, bile salts and vitamin D

Question 7

What is nieman pick disease ?

Answer 7

Genetic dificiency of sphinomyelinase

Question 8

What is the structure of sphingosine ?

Answer 8

18 carbon amino alcohol with unsaturated hydrocarbon chains

Question 9

What is the function of sphingomyelin ?

Answer 9

Coats axons of neurons, allows nerve transmission over distances

Question 10

What is sphingosine ?

Answer 10

An alternative to glycerol in some complex lipids

Question 11

What are some functions of sphingoids ?

Answer 11

1. Very abundant in brain extracts

2. Important in signal transmission and cell recognition

Question 12

What are sphingolipids ?

Answer 12

A class of lipids containing a backbone of sphingoid bases and aliphatic aminoalcohol

Question 13

What are PC-lecithins?

Answer 13

Emulsifying agents

Question 14

What are glycerophospholipids ?

Answer 14

Are glycerol based phospholipids, where 2 fatty acids and a phosphoric acid are attached

Question 15

Where do triglycerides and glycogen store energy ?

Answer 15

In the form of covalent bonds

Question 16

What happens in a beta oxidation catabolic process ?

Answer 16

A fatty acid is broken down in the mitochondria to generate CoA

Question 17

Where is rhodopsin attached and by what ?

Answer 17

The eye by a palmitoyl CoA fatty acid

Question 18

What is a fatty acid ?

Answer 18

A carboxylic acid with a long aliphatic tail

Question 19

What is the function of waxes ?

Answer 19

Provide surface coverings which prevent water loss

Question 20

What are adipocytes ?

Answer 20

They are fat cells. Continuous site of synthesis and breakdown of triglycerides. Oxidation provides caloric content

Question 21

What are triglycerides ?

Answer 21

Stored in adipose tissue, and is a major form of energy in plants and animals

Question 22

What are the three main functions of lipids ?

Answer 22

1. Energy storage and supply
2. Membrane components/surface coverings
3. Signals, messages, cofactors and pigments

Question 23

What are the classes of lipids ?

Answer 23

1. Simple lipids
2. Compound lipids
3. Derived lipids

Question 24

What are prostaglandins ?

Answer 24

Are diverse biological lipid molecules with many functions

Question 25

What are steroids ?

Answer 25

Organic compounds with 4 rings arranged in a specific orientation eg. cholesterol and sex hormones

Question 26

What are complex lipids ?

Answer 26

Consist of 2 or more structural moieties such as phospholipids, glycolipids

Question 27

What are waxes ?

Answer 27

Esters of long chain alcohols and fatty acids

Question 28

How is the charge spread in a non-polar molecule ?

Answer 28

Symmetrical

Question 29

In a polar molecule how is the charge distributed ?

Answer 29

Unequally

Question 30

What molecules are fat soluble ?

Answer 30

Non-polar

Question 31

Which molecules are water soluble ?

Answer 31

Polar molecules

Question 32

What do polar molecules have ?

Answer 32

One positive charge and the other end has a negative charge

Question 33

What have lipids got in common ?

Answer 33

1. They are mostly insoluble in water

2. They are soluble in solvents that have low polarity or are non-polar