lipids

Question 1

lipid solubility

Answer 1

• Insoluble, must be processed to a more transportable form

- Cannot diffuse to the absorptive surface

Question 2

Lipases

Answer 2

are water soluble
○ Only place enzyme and fat meet is oil-water interface
○ Is lipase is abundant, available surface area of lipid determines rate of hydrolysis

Question 3

Triglycerides

Answer 3

○ Glycerol and three fatty acids
○ Fuel
○ Storage and transport form of energy

Question 4

• Phospholipids

Answer 4

○ Glycerol, 2 fatty acids, phosphate

Question 5

phospholipids are good for

Answer 5

○ Membranes, lipid transport, nerve

Question 6

essential lipid vitamins

Answer 6

• Vitamins A, D, E, K

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Question 7

Cholesterol precursor for

Answer 7

○ Bile salts
○ Steroid hormones
○ Vitamin D

Question 8

cholesterol stored as

Answer 8

cholesterol esters (CE) (chol + fatty acids)

Question 9

LCTA/ACAT catalyses

Answer 9

esterification

cholesterol + fatty acid = cholesterol ester

Question 10

cholesterol esterases catalyse

Answer 10

hydrolysis

cholesterol ester to fatty acid + cholesterol

Question 11

lipases catalyse

Answer 11

hydrolysis

triglycerides to fatty acids and glycerol

Question 12

fatty acetyltransferases catalyse

Answer 12

esterification

fatty acids and glycerol to triglycerides

Question 13

bile acids from liver/gall bladder

Answer 13

• Detergents
  - Break up fat to make it water soluble
  - Water soluble enzymes can access them

Question 14

fatty acid transporter

Answer 14

fatty acid translocase FAT

fatty acid transport protein FATP

Question 15

cholesterol transporter

Answer 15

Niemann- Pick disease type C1 like 1 (NPC1L1)

Question 16

acyltransferases

Answer 16

• Triglycerides and cholesterol esters (by acyltransferases) reformed when inside the intestinal wall
  § Trapped inside the cell so they wont diffuse back out

Question 17

4 stages of burning fat

Answer 17

• Lipolysis (TAG -> FA)
  - Activation (CoA addition - requires ATP)
  - Transport into mitochondrion (requires carnitine)
  - B-oxidation (yields FADH, NADH, Acetyl-CoA)

Question 18

3 things that happen as a response to too much cholesterol

Answer 18

• Inhibit synthesis
  § Inhibition of HMG-CoA reductase activity
  - Block uptake
  § Reduced LDL- receptor (LDLR) expressed
  - Safer storage
  § Stimulates acyl CoA: cholesterol acyl transferase (ACAT)

Question 19

Plasma cholesterol

Answer 19

• LDL (and other remnant lipoproteins) oxidise readily
  
  • Is then taken up by macrophages in artery walls
  • Damage to endothelium and underlying smooth muscle
  • Restricted blood flow, increase BP, endothelial dysfunction