REVISION GUIDE LIVER: FAT Flashcards Preview

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Flashcards in REVISION GUIDE LIVER: FAT Deck (69)
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1

what are lipids?

they are esters of fatty acids and glycerol or other compounds (cholesterol)

2

what is the structure of a tri(acyl)glyceride (TAG)?

1 glycerol molecule esterified to 3 fatty acid chains at their carboxyl heads

3

what are the storage areas of fat in the body?

adipocytes
hepatocytes
elsewhere

4

what are fatty acids?

they are the building blocks of lipids

5

what is the difference between saturated and unsaturated fatty acids?

saturated = single C-C bonds - they line up
unsaturated = at least 1 C=C double bond - they kink and need more space

6

what proportion of western diets is fat?

dietary fats are on average 1/3 of western diet

7

what type of fats are the majority that are found in western diets?

90% of dietary fats are triglyerides

8

what are the different types of of fats found in diets?

triglycerides
cholesterol esters
phospholipids
fat-soluble vitamins

9

what are the functions of lipids?

energy reserve
structural - part of cell membranes
inflammatory cascades
hormone metabolism

10

how are lipids involved in hormone metabolism?

cholesterol is the backbone of adrenocorticoids and sex hormones

11

how is cholesterol esterified?

it is esterified intracellularly in lipoprotein by:
acyl-CoA (cholesterol acyltransferase)
lecithin (cholesterol acyltransferase)

12

where is the majority of cholesterol processed in the body?

in the liver

13

what proportion of cholesterol is endogenous and what proportion is derived from diet?

90% of cholesterol is endogenous
10% of cholesterol is dietary

14

how is cholesterol excreted from the body?

through bile in enterohepatic circulatory system

15

how do triglycerides and cholesterol travel in blood?

bound to lipoproteins

16

which molecules provide the most energy in the body?

almost all energy is provided through oxidation of lipids
lipids > carbohydrates > proteins

17

how much energy do lipids yield?

9-10 kcal/g

18

what are the different energy reserves in the body?

- blood glucose
- glycogen stores
- muscle protein
- lipid reserve

19

how much energy is stored in blood glucose and how long does it last for?

40 kcal
lasts for a few minutes

20

how much energy is stored in glycogen stores and how long does it last for?

600 kcal
approx. a day

21

how much energy is stored in muscle protein and how long does it last for?

25,000kcal
7-10 days

22

how much energy is stored in lipid reserve and how long does it last for?

100,000 kcal
30-40 days

23

where is the main storage place for glycogen?

the liver

24

what is the structure of lipoproteins?

consists of:
- a core containing TGs and cholesterol esters
- a surface monolayer of phospholipids, cholesterol and specific protein (eg apoproteins)

25

what determines the density of lipoproteins?

the protein to lipid ratios

26

what is the role of chylomicrons?

they carry lipids from the gut to muscle and adipose tissue

27

what happens to chylomicron remnants in blood?

the remnants are taken up by the liver via receptor mediated endocytosis - there is recognition of ApoE by hepatocyte surface receptors

28

what is the structure of chylomicrons?

largest and lowest density lipoprotein
has high lipid to protein ratio
has highest triglyceride content

29

what is the structure of VLDL?

is 2nd highest in triglycerides as a percentage of their weight

30

what is the structure of LDL?

have the highest amount of cholesterol esters as a percentage of their weight