Jenney Exam 2

Question 1

How is fatty acid regulated?

Answer 1

By its rate limiting steps vis acetyl CoA carboxylase

Question 2

What are the four levels of fatty acid regulation?

Answer 2

Transcriptional regulation
Polymerization (allosteric)
Phosphorylation
Hormones

Question 3

How does polymerization work?

Answer 3

ACC is active when it is a polymer
Citrate activates polymerization
Palmitoyl CoA inactivates polymerization

Question 4

How does phosphorylation work?

Answer 4

When the enzyme is not phosphorylated the Ki for palmitoyl CoA is high nd Km for citrate is low

Question 5

What are the hormones in fatty acid regulation and what do they do?

Answer 5

Insulin: triggers activation of citrate lyase and stimulates fatty acid synth, ACC de-phosphorylation
Glucagon and epinephrine: trigger inactivation of enzyme ACC and stimulation beta oxidation

Question 6

What are the enzymes of the TCA cycle?

Answer 6

Citrate synthase
Aconitase
Isocitrate Dehydrogenase
Alpha-ketoglutarate dehydrogenase complex
Succinyl-CoA synthetase 
Succinate dehydrogenase 
Fumarase
Malate dehydrogenase

Question 7

What are the product of the TCA cycle?

Answer 7

1 CoASH
3NADH
1 FADH2
1 GTP
2 CO2
3H+

Question 8

How is the TCA cycle regulated?

Answer 8

Pyruvate carboxylase 
Pyruvate dehydrogenase
Citrate synthase  
Isocitrate dehydrogenase 
Alpha-ketoglutarate dehydrogenase

Question 9

What inhibits pyruvate dehydrogenase complex?

Answer 9

Acetyl CoA
NADH
ATP

Question 10

What activates pyruvate dehydrogenase complex?

Answer 10

NAD+

CoA

Question 11

What activates pyruvate carboxylase?

Answer 11

Acetyl CoA
ATP
NADH

Question 12

What is pyruvate carboxylase inhibited by?

Answer 12

NAD+

CoASH

Question 13

What is citrate synthase inhibited by?

Answer 13

ATP
NADH
Succinyl-CoA

Question 14

What is isocitrate dehydrogenase inhibited by?

Answer 14

ATP

NADH

Question 15

What is isocitrate dehydrogenase activated by?

Answer 15

ADP

Question 16

What is alpha-ketoglutarate dehydrogenase inhibited by?

Answer 16

NADH

Succinyl-CoA

Question 17

What is activates alpha-ketoglutarate dehydrogenase?

Answer 17

AMP

Question 18

What are some symptoms of defects in beta oxidation?

Answer 18

Hypoglycemia: carnitine is reabsorbed by the kidneys, fatty acids cant be broken down to provide glucose
Dicarboxylic aciduria

Question 19

What type of chain would you most likely see a defect in beta oxidation?

Answer 19

Medium fatty acid chain

Question 20

What occurs in digestions of lipids?

Answer 20

Lipases chop fatty acids off triacylglycerides

Bile salts emulsify fats

Question 21

What are the lipases which aid in digestion?

Answer 21

Lingual (short chain)
Gastric
Pancreatic

Question 22

Describe chylomicrons.

Answer 22

Largest and least dense lipoproteins

Highest concentration of triacylglycerols (TAGs)

Question 23

What do TAGs form?

Answer 23

Large globules
Broken down by lipases
Emulsified by bile salts and phospholipids into micelles
Absorbed in the brush border

Question 24

How are fatty acids and micelle components partitioned across the water layer?

Answer 24

Passive diffusion and fatty acid transporters

Needs a low conc of fatty acids in cells

Question 25

How do enterocytes remove fatty acids to maintain this low conc in cells?

Answer 25

Fatty acid binding proteins

Question 26

How are bile salts reabsorbed?

Answer 26

Happens further along intestine b/c not reabsorbed with fats Active transport in the ileum Passive transport occurs in small intestine and colon

Question 27

What occurs with the majority of cholesterol?

Answer 27

Esterified and makes it harder to absorb into micelle

Question 28

Which types of fatty acids are directly absorbed into portal vein?

Answer 28

Short chain fatty acid (less than 14) Polyunsaturated fatty acid Complex with serum albumin or bound to lipoprotein

Question 29

What is the function of ApoE related to lipid metabolism?

Answer 29

Hepatic clearance of antherogenic lipoprotein Sequesters excess cholesterol at lesion sites Co-factor for enzymes involved in HDL maturation

Question 30

What is the function of ApoE independent to lipid metabolism?

Answer 30

``` Anti-inflam activity Anti-oxidant: inhibits LDL oxidation Supress apoptosis Prevents LDL retention in artery wall Inhibit platelet aggregation ```

Question 31

What are the possible genetic treatments revelent to ApoE and ApoB-100?

Answer 31

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