lipids

Question 1

What are the 5 classes of lipids?

Answer 1

Fatty acids
Triacyl glycerides (fats and oils)
Glycerophospholipids (membrane lipids)
Sphingolipids (membrane lipids)
Cholesterol

Question 2

What do you call a 12 carbon saturated fatty acid?

Answer 2

Lauric acid

Question 3

What do you call a 14 carbon saturated fatty acid?

Answer 3

Myristic acid

Question 4

What do you call a 16 carbon saturated fatty acid?

Answer 4

Palmitic acid

Question 5

What do you call a 18 carbon saturated fatty acid?

Answer 5

Stearic acid

Question 6

What do you call a 20 carbon saturated fatty acid?

Answer 6

Arachidic acid

Question 7

What do you call a unsaturated 16 carbon fatty acid with 1 double bond?

Answer 7

Palmitoleic acid

Question 8

What do you call a unsaturated 18 carbon fatty acid with 1 double bond?

Answer 8

Oleic acid

Question 9

What do you call a unsaturated 18 carbon fatty acid with 2 double bonds?

Answer 9

Linoleic acid

Question 10

What do you call a unsaturated 18 carbon fatty acid with 3 double bonds?

Answer 10

Linolenic acid

Question 11

What do you call a unsaturated 20 carbon fatty acid with 4 double bonds?

Answer 11

Arachidonic acid

Question 12

What is omega nomenclature ?

Answer 12

Another labelling system indicating position of double bonds in fatty acids

Question 13

What are fatty acids precursors for?

Answer 13

Prostaglandins, thromboxanes, leucotrienes

Question 14

Which two fatty acids are precursors to arachidonic acid ?

Answer 14

Linoleic acid
Eicosatreinoic acid

Question 15

What are triacylglyerols transported by?
Where are they stored?

Answer 15

Lipoproteins - very low density lipoproteins (VLDL)
Adipocytes

Question 16

What are the steps of the transport of triacylglycerols?

Answer 16

1. Transported by VLDLs to fat cells
2. Lipoprotein lipase splits triacylglycerols into acyl-CoA
3. Glucose is taken up and metabolised into glycerol-3-p as needed to form storage triacylglycerols
4. Taken up into fat cells
5. If body needs energy, stored triacylglycerols are metabolised by hormone sensitive lipase into flycrol and fatty acids
6. Fatty acids released into blood and transported in form of f aid-albumin complex

Question 17

What are chylomicrons ?

Answer 17

Lipoproteins that transport diet triglycerides, cholesterol and other lipids - from intestine to fat tissue and liver.

Question 18

What are VLDLs?

Answer 18

Lipoproteins that transport triglycerides from liver to fat tissue

Question 19

What are LDLs?

Answer 19

Low-density lipoproteins that transport cholesterol from liver to peripheral tissue

Question 20

What are HDLs ?

Answer 20

High density lipoproteins that transport cholesterol and phospholipids from peripheral tissue to liver

Question 21

What are glycerophospholipids?

Answer 21

Main components of cell membranes
Amphiphilic compounds

Question 22

How are glycerophospholipids cleaved and absorbed ?

Answer 22

Cleaved by phospholipases of the pancreas
Resorbed in digestive tract
Cleaved into building blocks by phospholipases before resorption
Before cleaving can occur, glycerophospholipids need to be emulsified by bile

Question 23

What are sphingolipids?

Answer 23

Made up of fatty acids , sphingosine, phosphate and choline.
Amphiphilic

Question 24

Breakdown of sphingolipids by lysosomal enzymes

Answer 24

Deficiency of enzymes = accumulation of substrates in the lysosome
Deficiency of ganglioside neuraminidase = neurogenerative disorder - so essential a foetus with a deficiency cannot survive

Question 25

What is Gangliosidosis ?

Answer 25

Major symptoms:
- mental retardation
- liver enlargement
- skeletal involvement
- death by age 2

Principle storage substance:
Ganglioside Gm1

Question 26

What is Tay-Sachs disease?

Answer 26

Symptoms:
Mental retardation
Blindness
Death by age 3

Principle storage substance:
Ganglioside Gm2

Question 27

What is Fabry’s disease ?

Answer 27

Symptoms:
Skin rash
Kidney failure
Pain in lower extremities

Principle storage substance:
Trihexosyl-ceramide

Question 28

What is sandhoff’s disease ?

Answer 28

Symptoms:
Mental retardation
Blindness
Death by age 3
More rapidly progressing than Tay-Sachs disease

Principle storage substance:
Ganglioside Gm2 and globoside

Question 29

What is gauchers disease?

Answer 29

Symptoms:
Liver and spleen enlargement
Erosion of long bones
Mental retardation in infantile form

Principle storage substance:
Glucocerebroside

Question 30

What is Niemann-Park disease?

Answer 30

Symptoms:
Liver and spleen enlargement
Mental retardation

Principle storage substance:
Sphingomyelin

Question 31

what is Farber’s lipo-granulomatosis?

Answer 31

Symptoms:
Painful and progressive deformed joints
Skin nodules
Death within a few years

Principle storage substance:
Ceramide

Question 32

What is Krabbe’s disease?

Answer 32

Symptoms:
Loss of myelin
Mental retardation
Death by age 2

Principle storage substance:
Deacylated galactose-cerebroside

Question 33

What is sulfatide lipidosis?

Answer 33

Symptoms:
Mental retardation
Death in first decade

Principle storage substance:
Sulfatide

Question 34

What is cholesterol?

Answer 34

Weakly amphiphilic
Condensed 4 ring system - aka steroid ring system
Dietary intake - 300mg/day
Endogenous synthesis - 1000 mg/day
Site of cholesterol synthesis - all cells

Question 35

What is cholesterol a precursor for?

Answer 35

Glucocorticoids
Mineralcortocoids
Vitamin D
Estrogens
Protestagens
Androgens e.g testosterone
Bile acids

Question 36

How are fatty acids metabolised?

Answer 36

Broken down to acetyl CoA via B-oxidation

Glycolysis - glucose to glycerol/ acetyl Co-A
Gluconeogenesis - glycerol to glucose
Fatty acid synthesis - Acetyl Co-A to fatty acids
B-oxidation - fatty acids to acetyl Co-A

Palmitate converts fatty acids to ceramide