Review III

Question 1

2 enzymes involved in fatty AcCoA?

Answer 1

• Acetyl CoA carboxylase: converts AcCoA to fatty AcCoA

- Carnitine palmitoyltransferase I – converts fatty AcCoA to AcCoA

Question 2

What activates AcCoA carboxylase?

Answer 2

• Insulin

- Citrate

Question 3

What activates carnitine plamitoyltransferase?

Answer 3

Epinephrine

Question 4

What is rate limiting enzyme in Fatty acid synthesis?

Answer 4

AcCoA carboxylase

Question 5

What does AcCoA carboxylase do?

Answer 5

• Catalyzes formation of malonyl-CoA from Acetyl-CoA

Question 6

Cofactor for AcCoA carboxylase?

Answer 6

• Biotin - carries activated CO2

Question 7

What are triglycerides converted into?

Answer 7

Glycerol and fatty acids

Question 8

What is HSTL?

Answer 8

• Breaks down triglycerides into fatty acids and glycerol

- Hormone sensitive triacylglycerol lipase

Question 9

What is glycerol used for?

Answer 9

Used by the liver for gluconeogenesis

Question 10

What does beta oxidation increase?

Answer 10

• Ketone body formation

- Increases ATP which facilitates gluconeogenesis

Question 11

What supplies ATP needed for gluconeogenesis?

Answer 11

Fatty acid beta oxidation

Question 12

What does carnitine do?

Answer 12

• Carnitine transports fatty acid into the mitochondrial matrix

Question 13

What is Malonyl CoA?

Answer 13

• First precursor in the synthesis of fatty acids
• Produt of reaction catalyzed by AcCoA carboxylase
  • Decreased malonyl CoA increases fatty acid beta oxidation

Question 14

What does Excess of malonyl CoA do?

Answer 14

• Inhibits CPT I

- Inhibits fatty acid beta oxidation reducing ketone body formation

Question 15

Another name for Keton body?

Answer 15

• beta-hydroxybutyrate

Question 16

What is HMG CoA synthase?

Answer 16

• Converts acetyl CoA to beta-hydroxybutyrate

Question 17

What does thiophorase do?

Answer 17

Converts beta-hydroxybutyrate to AcCoA

Question 18

What inhibits AcCoA Carboxylase?

Answer 18

• Increased glucagon and epinephrine inhibit acetyl CoA carboxylase

Question 19

What does malonyl CoA do?

Answer 19

Inhbitis CPT1

Question 20

What is Mevalonate?

Answer 20

First key intermediate in cholesterol biosynthesis

Question 21

What is HMG-CoA reductase?

Answer 21

• Rate-limiting enzyme in cholesterol biosynthesis

- Forms mevalonate

Question 22

Pathway of cholesterol synthesis?

Answer 22

• AcCoA converted to acetoacetylCoA
• AcetoacetylCoA converted to HMG CoA
• HMG CoA is acted on by HMG CoA reductase and NADPH generating mevalonic acid/ mevalonate

Question 23

What inhibits HMG CoA reductase?

Answer 23

Statins

Question 24

How do statins work?

Answer 24

• Reduces cholesterol biosynthesis by stopping HMG CoA reductase
• Leads to upregulation of LDL receptors
• Body attempts to absorb remaining cholesterol in the blood

Question 25

What does 7 alpha hydroxylase do?

Answer 25

Degrades cholesterol to make bile acids

Question 26

What makes cholesterol esters?

Answer 26

ACAT (acyl-CoA acyltransferase)

Question 27

What transports dietary lipids?

Answer 27

Chylomicrons

Question 28

What transports endogenous lipids?

Answer 28

- VLDL - IDL - LDL

Question 29

Functions of lipoproteins?

Answer 29

1. Cofactor for enzymes 2. Ligand for extracellular functional receptor 3. Structural proteins for lipo proteins

Question 30

What does Apo-CII do?

Answer 30

Activates lipoprotein lipase

Question 31

What does Apo-AI do?

Answer 31

Activates lecithin:cholesterol acyltransferase (LCAT)

Question 32

What is Apo E?

Answer 32

– remnant receptor

Question 33

What isApo B-100?

Answer 33

- LDL receptor | - Allows LDL to attach to the cognate LDL receptor

Question 34

What is Apo A-I?

Answer 34

– HDL receptor

Question 35

What is B-48?

Answer 35

Structural protein for chylomicrons

Question 36

What is B-100?

Answer 36

Structural protein for VLDL and LDL

Question 37

What is A-1?

Answer 37

Structural protein for HDL

Question 38

HOw does liver handle vitamin A?

Answer 38

- When blood levels of vitamin A decrease, liver mobilizes the vitamin by hydrolyzing the retinyl ester - Retinol then binds to retinol-binding protein, which is then secreted into the blood

Question 39

How does liver handle vitamin D?

Answer 39

- Transported in chylomicrons in nonesterified form - Major vitamin D stores – adipose tissue and skeletal muscle - Liver responsible for initial activation of D3 to 25 hydroxycholecalciferol - Liver synthesizes vitamin D-binding protein

Question 40

Where is major store of Vitamin K?

Answer 40

Skeletal muscle

Question 41

What does vitamin K do?

Answer 41

Required for prothrombin synthesis

Question 42

What usually provides fumarate?

Answer 42

Succinyl CoA

Question 43

What can provide fumarate in absence of siccinyl CoA

Answer 43

Phenylalanine Aspartate Tyrosine

Question 44

What usually provides succinyl CoA?

Answer 44

Alpha ketoglucarae

Question 45

What also can provide succinyl CoA?

Answer 45

Propylin CoA via: Valine Isoleucin