Glycerides and Non-Glycerides lipids

Question 1

What are the recommended amounts of omega-3 fatty acids

Answer 1

at least 2 portions of fish per week, of which one should be oily.
2 portions of fish per week, one white and one oily, contain approximately 0.45g/d LC n-3 PUFA.

Question 2

What are glycerides

Answer 2

they are lipid esters made of glycerol and fatty acids

Question 3

What are the 2 classes of glycerides

Answer 3

Neutral glycerides - nonionic & nonpolar eg triglyceride
Phosphoglycerides - have a polar region, the phosphoryl group & a nonpolar fatty acid tail

Question 4

What does esterification of glycerol with fatty acid make

Answer 4

a neutral glyceride and water

Question 5

What does esterification make

Answer 5

mono, di and tri glycerides

Question 6

What is a phosphoglyceride

Answer 6

they are phosphate esters that are charged and are central to the structure and function of cell membranes
Phosphate group = polar head (hydrophilic)
Alkyl chain of FA = nonpolar tail (hydrophobic)

Question 7

What are sphingolipids

Answer 7

Not derived from glycerol - derived from sphingosine
a long chain, nitrogen containing alcohol and are the structural components of cellular membranes

Question 8

what are sphingomyelins

Answer 8

phospholipids that are located throughout the body
Important for structural components of nerve cell membranes
Found in myelin sheath (25% are sphingomyelins) & insulate cells of the CNS
Essential to proper cerebral function & nerve transmission

Question 9

what are glycosphingolipids

Answer 9

Also called glycolipids:
cerebrosides
sulfatides
gangliosides

Built on a ceramide backbone structure which is a fatty acid amide derivative of sphingosine

Question 10

what are sterols

Answer 10

Lipids containing multiple rings of carbon atoms
Crucial components of cell membranes and many hormones
Manufactured in our bodies and therefore are not essential components of our diet

Question 11

what are steroids

Answer 11

have a nucleus made of 4 fused 5 carbon rings e.g sex hormones

Question 12

what is cholesterol

Answer 12

most abundant steroid and is amphipathic and found in large concentrations in the brain, spinal cord and liver

Question 13

where is cholesterol synthesised from

Answer 13

acetic acid

Question 14

where is cholesterol excreted from the liver as

Answer 14

bile

Question 15

what is can cholesterol disease cause

Answer 15

Atherosclerosis; high blood pressure; coronary heart disease & others

Question 16

how can cholesterol levels be reduced

Answer 16

Drugs: HMG-CoA reductase inhibitors (statins), such as lovastatin (Mevacor) and atorvastatin (Lipitor)
Regular exercise

Question 17

what are complex lipids

Answer 17

Lipids that are bound to other types of molecules

Most important – plasma lipoproteins which are required to transport other lipids

4 major classes of human plasma lipoproteins

Question 18

what are the 4 lipoproteins

Answer 18

1. chylomicrons
2. VLDL very low density lipoprotein
3. LDL low density lipoprotein
4. HDL high density lipoprotein

Question 19

what are apolipoproteins

Answer 19

proteins synthesised in the liver that binds to lipids to form lipoproteins. They have a structural role and are co-factors for enzymes and have 6 classes: A,B,C,D,E,H

Question 20

What bilayer does the plasma membrane have

Answer 20

a bilayer of phospholipids and is called the fluid mosaic model with a Hydrophilic phospholipid head (outside) and a hydrophobic tail (inside)

Question 21

Why is is called fluid mosaic model

Answer 21

It is mosaic as Proteins and substances such as cholesterol become embedded in the bilayer, giving the membrane the look of a mosaic.
It is fluid as has a consistency of oil at body temperature which allows proteins and other substances to cross it.

Question 22

what is embedded in the surface of fluid mosaic model

Answer 22

cholesterol - makes it more stable and stop solidifying when body temp is low

Question 23

what chains attach to the outer surface of the plasma membrane

Answer 23

carbohydrate chains - they are specific to everyone and give people characteristics e.g blood type.

Question 24

what are isoprene’s

Answer 24

Large diverse group of lipids – all compounds are built from 1 or more 5-carbon units called isoprene
Generic term = terpene