Chapter 27 - Lipid Oxidation

Question 1

4 classes of lipid

Answer 1

• fatty acids
• triacylglycerols (triglycerides)
• phospholipids
• cholesterol

Question 2

Fatty acid carbon atoms are usually numbered beginning with…

Answer 2

the carboxyl terminal carbon atom

Question 3

Carbom atoms 2 and 3 are referred to as..

Answer 3

alpha and beta

Question 4

Fatty acids can also be numbered from the methyl carbon atom, which is called….

Answer 4

omega carbon

Question 5

fatty acids, a major source of energy, are stored as….. in adipose tissue

Answer 5

triacylglycerols in lipid droplets

Question 6

adipose tissue depots

Answer 6

• pulmonary
• periadventitial
• perirenal
• bone marrow
• epicardial
• subcutaneous
• visceral

Question 7

triacylglycerols

Answer 7

the most concentrated form of stored energy available to animals; 37kJ/g
-highly reduced

Question 8

Carbohydrates energy content

Answer 8

16 kJ/g

Question 9

protein energy content

Answer 9

17 kJ/g

Question 10

triacylglycerols are stored in what form?

Answer 10

anhydrous

Question 11

Which get depleted quicker… triacyglycerols or glycogen?

Answer 11

glycogen; only lasts hours

Question 12

Excessive triacylglycerol storage in adipose tissue can lead to..

Answer 12

obesity

Question 13

High levels of triacylglycerol in blood can lead to…

Answer 13

heart attack/stroke

Question 14

Since triacylglycerol is too hydrophobic to cross biological membranes, how is it transported/digested (in the small intestine)??

Answer 14

it is degraded in the small intestine and resynthesized in intestinal mucosal cells

Question 15

lipases

Answer 15

break down lipids

Question 16

chylomicron

Answer 16

a lipoprotein synthesized only in intestine that allow for transport of insoluble lipids in the blood stream to tissues

Question 17

chylomicron composition

Answer 17

phospholipid and cholesterol on the surface, triacylglycerol in the core

Question 18

lipoprotein lipase

Answer 18

bound to cell surface and releases all 3 fatty acids from each TG

Question 19

lipid droplets

Answer 19

• have a phospholipid monolayer instead of bilayer

- core is hydrophobic where TG is stored

Question 20

perilipin

Answer 20

• protein on surface of lipid droplet
• barrier to lipases
• prevents unwanted TG breakdown

Question 21

lipolysis

Answer 21

TG broken down to glycerol and 3 FA

• phosphorylation of perils-in allows lipase access to TG in lipid droplet
• activates adipose tissue TG lipase

Question 22

phosphorylation of hormone sensitive lipase

Answer 22

activates hormone sensitive lipase

Question 23

Fate of fatty acid and glycerol

Answer 23

glycerol goes to liver, FA to muscle

Question 24

FA oxidation occurs in..

Answer 24

the mitochondria

Question 25

To be oxidized, FA needs to be:

Answer 25

- activated (bound to CoA) | - transported (carnitine shuttle)

Question 26

fatty acyl CoA

Answer 26

a generic term describing any fatty acid bound to CoA

Question 27

Activation of fatty acid to fatty acid CoA (reversible)

Answer 27

- fatty acid reacts w/ ATP to form an acyl adenylate and other two phosphorylation groups of ATP substrate are released as pyrophosphate - the sulfhydryl group of CoA attacks acyl adenylate to form acyl CoA and AMP

Question 28

Activation of acid to fatty acid CoA driven by?

Answer 28

hydrolysis of pyrophosphate by pyrophosphates to 2 organic phosphates

Question 29

transportation of fatty acid CoA

Answer 29

The acyl group is transferred from the sulfur atom of CoA to the hydroxyl group of carnitine to form acyl carnitine.

Question 30

transportation of fatty acid CoA catalyzed by:

Answer 30

carnitine acyltransferase I, which is bound to the outer mitochondrial membrane:

Question 31

rate-limiting step of fatty acid oxidation

Answer 31

fatty acid transport into the mitochondria

Question 32

carnitine shuttle while fasting

Answer 32

highly active

Question 33

carnitine shuttle while fed

Answer 33

low activity

Question 34

4 basic steps of B-oxidation of saturated fatty acids (degradation of fatty acids)

Answer 34

- oxidation - hydration - oxidation - cleavage

Question 35

Overall equation for the oxidation of palmitate

Answer 35

Palmitoyl CoA + 7CoA +7FAD + 7NAD+ + 7H2O --> 8Acetyl CoA + 7FADH2 + 7NADH + 7H+

Question 36

Net ATP production of oxidation of palmitate?

Answer 36

106 ATP

Question 37

Enoyl CoA isomerase

Answer 37

- moves double bond from C3-4 to C2-3 | - changes double bond from cis to trans

Question 38

ketone bodies

Answer 38

- alternative to glucose as a fuel or energy source - formed by ketogenesis in liver - produced at low rate - utilized by extra hepatic tissues when glucose is low(starvation) - used after several days of fasting (prevents use of protein and tissue breakdown)

Question 39

condensation of 3 acetyl CoA forms?

Answer 39

acetoacetate

Question 40

acetoacetate is converted to what

Answer 40

3-hydrocybutyrate and acetone

Question 41

Metabolism of Ketone Bodies in extrahepatic tissues (brain) occurs in?

Answer 41

the mitochondria

Question 42

excess production of ketone bodies can lead to ..

Answer 42

acidosis