Lipids

Question 0

What type of lipids are there?

Answer 0

1) Simple lipids (fatty acids; triacyeglycerols di mono; waxes)
2) Compound lipids (phospholipids, glycolipids, lipoproteins)
3) Derived lipids (derivates such as sterols and straight chain alcohols)

Question 1

How do larger lipids travel through circulation and why are these necesarry?

Answer 1

via chylomicrons, HDL, LDL’s and VLDL. These are necessary as they are hydrotrophic, they are water soluble and help the lipids transport.

Question 2

What are lipids stabilised by?

Answer 2

polar bile salts

Question 3

Where do the Micelles interact?

Answer 3

at the brush boarder

Question 4

Where does the lipid part of the micelle diffuse?

Answer 4

out of the micelles and into the enterocytes on a concentration gradient

Question 5

What happens after lipid absorption?

Answer 5

re-formation or re-esterification of triacylglycerols, phosphatiolylcholine and cholesteryl esters take place.

Question 6

What do short chain fatty acids attach to for transport to other tissues and blood?

Answer 6

albumin

Question 7

What are the primary form of lipoproteins formed from exogenous lipids?

Answer 7

Chylomirons

Question 8

What other lipoproteins that transport endogenous lipids from tissue to tissue?

Answer 8

VLDL’s, LDL’s, and HDL’s

Question 9

What are VLDL’s made up of?

Answer 9

high levels of triaylglycerol (TAG) an less protein and cholesterol

Question 10

What are LDL’s made up of?

Answer 10

Less triacylglycerol, higher protein and highest cholesterol

Question 11

What are HDL’s made up of?

Answer 11

the lowest amount of triacylgycerol, highest protein and intermediate cholesterol. (which delivers back to the liver)

Question 12

What are Apolipoproteins?

Answer 12

they are the protein component of the lipoproteins that stabilise the lipoproteins as they circulate in the blood.

Question 13

What makes apolipoproteins so important to lipoproteins?

Answer 13

they allow lipoproteins to be recognised by specific cell receptors and stimulates certain enzymatic reactions.

Question 14

In a sample of blood under a microscope, what is it that can be seen floating around in the blood plasma?

Answer 14

chylomicrons

Question 15

What is the distribution process of lipids in the body?

Answer 15

• the lipid leaves the enterocyte in the form of chylomicrons, which then undergo conversion to chylomicron remnants.
• lipoproteins first appear in the lymphatic vessels of the abdominal region then enter the blood stream at a slow rate.

Question 16

how long after eating a fatty meal do chylomicrons still enter the blood stream?

Answer 16

up to 14 hours after eating

Question 17

when is the blood plasma lipid level at its peak?

Answer 17

30 minutes to 3 hours after eating

Question 18

What accounts for the milking appearance of fats? (turbidity)

Answer 18

the large triacylglycerol laden chylomicrons

Question 19

what are chylomicron remnants?

Answer 19

small particles left after lipolytic action that is richer in cholesterol rather than triacylglycerols

Question 20

what is a liver cell endocytosis?

Answer 20

the removal of chylomicron remnants from the blood stream

Question 21

What is the main component of pile and what generates it?

Answer 21

Cholesterol is the main component of bile and the liver is what generates it

Question 22

What types of cells in the body have the ability to oxidise free fatty acids and hydrolise diacylglycerols for energy?

Answer 22

Muscle cells

Question 23

What type of fat deposits to aerobically trained muscle contain?

Answer 23

triacylglycerols

Question 24

What are the 4 action of the liver in lipid metabolism?

Answer 24

1) synthesis of bile salts for digestion and absorption of dietary fats 2) synthesis of lipids from non-lipid precursors, i.e glucose and amino acids 3) can take up and catabolise exogenous lipids or use these for re-synthesis of other lipids 4) The synthesis of fatty acids, triacylglycerols, VLDL, HDL, LDL, glycerol, cholesterol, monoacylglycerols and diacylglycerols.

Question 25

Chylomicron remnant cholesterol and cholesteryl esters may be (3):

Answer 25

a) converted to bile salts and secreted in the bile b) secreted into the bile as neutral sterols c) incorporated into VLDL or HDL and released into plasma

Question 26

What are the roles of an adipocyte in lipid metabolism? (4)

Answer 26

- it is a major storage site - fat constitutes for 85% of the adipose cell - insulin increase the availability and uptake of fatty acids by stimulating lipoprotein lipase. - cellular glucose provides the source of glycerophosphate for re-estification with the fatty acids from triacylglycerols.