Lipids Flashcards Preview

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Flashcards in Lipids Deck (40):
1

What do lipids exist as in adipose tissue?

lipid droplets

2

What do lipids exist as in blood?

lipoproteins

3

What is the structure of fatty acids?

Hydrophobic hydrocarbon 'tail' and hydrophilic terminal carboxyl group

4

What is the name of the lipid class that gives rise to blood group antigens?

glycolipids (consitituent of membranes)

5

What makes a fatty acid unsaturated?

has one or more double bonds that kink the hydrocarbon chain, liquid

6

What are examples of essential fatty acids?

linoleic and alpha linolenic acid

7

What are good fatty acids?

high in polyunsaturated fatty acids

8

What are bad fatty acids?

high in saturated fatty acids

9

What are really bad fats?

trans fatty acids resulting from hydrogenation of vegetable oils

10

What is linoleic acid a substrate for?

prostaglandins and arachidonic acid which is a precursor of eicosanoids (signalling molecule)

11

What is linolenic acid a substrate for?

omega 3 fatty acids

12

What do omega 3 fatty acids do?

lower plasma cholesterol preventing atherosclerosis and lowers TAG preventing obesity

13

What are triacylglycerols?

esters of fatty acids and glycerol which are uncharged and water insoluble therefore form droplets

14

What do TAGs do?

dietary fuel and insulation

15

What are phospholipids composed of?

2 fatty acids and glycerol and a phosphate group

16

What does 'amphipathic' mean?

Has both hydrophilic and hydrophobic parts

17

What is the main dietary lipid?

TAG

18

Where is the main site of lipid digestion?

small intestine

19

What enzymes digest lipids?

lipases

20

What is lipid digestion promoted by?

emulsiification by bile salts and peristalsis

21

What do bile salts do?

act as biological detergents to form emulsions and mixed micelles
are derivatives of cholesterol
saves lipids coalescing in an aqueous environment

22

How do we digest TAG?

degraded in small intestine by pancreatic lipase to monoacylglycerol and 2 fatty acids as is too big to be taken up by mucosal cells in intestinal villi

23

What are cholesterol esters digested to?

cholesterol and free fatty acid

24

What are phospholipids hydrolysed to?

FA and lysophospholipid

25

How are digested lipids absorbed?

products form mixed micelles with bile salts
mixed micelles approach brush border membranes of enterocytes and release lipid products which enter cells by diffusion

26

What FAs don't need micelles for absorption?

short and medium chain FAs

27

What is steatorrhea?

excess fat in faeces due to lipid malabsorption

28

What patients are prone to developing steatorrhea?

cystic fibrosis affected patients

29

What are 2 possibilities of the utilisation of dietary lipids after fatty acids are absorbed?

intestinal cells resynthesises TAG, phospholipid, cholesterol ester for export
or are packaged into chylomicrons to make them soluble and released into lymph by exocytosis and then into blood

30

What does lipoprotein lipase do?

hydrolyses TAG in chylomicrons to FA and glycerol

31

Where is lipoprotein lipase mainly found?

in capillaries of skeletal muscle and adipose tissue

32

Where do chylomicron remnants go?

liver

33

What is glycerol in the liver used to do?

produce glycerol-3-phosphate which can be used in glycolysis and gluconeogenesis

34

How are FAs released from stored TAG in tissues?

Hormone sensitive lipase (HSL)

35

What is HSL activated by?

phosphorylation in response to epinephrine

36

How are free FAs transported in the blood?

lipoproteins
in complex with serum albumin

37

What do chylomicrons carry and from where to where?

TAG
intestine to tissues

38

VLDL carry and to where?

TAG
liver to tissue

39

LDL

cholesterol
to tissues

40

HDL

cholesterol
tissue to liver for elimination