KETONE METAB

Question 1

Three kinds of ketone bodies

Answer 1

acetoacetate, b-hydroxybutyrate and acetone

Question 2

Site of Ketogenesis

Answer 2

mitochondrial matrix of the liver

Question 3

how many molecules of Acetyl CoA is utilized in the first step of Ketone biosynthesis

Answer 3

2 molecules of Acetyl CoA

Question 4

3rd molecul of Acetyl CoA in ketone biosynthesis is condensed with what and through what enzyme

Answer 4

acetoacetyl CoA via HMG CoA synthase

Question 5

Where is HMG CoA Synthase only present in?

Answer 5

Mitochondrial matrix of the liver

Question 6

What is a precursor of Cholesterol and also an intermediate in the catabolism of Leuicine?

Answer 6

HMG CoA?

Question 7

What is produced when Acetyl CoA is condensed with Acetoacetyl CoA?

Answer 7

HMG CoA

Question 8

HMG CoA is common to what two pathways?

Answer 8

Ketone Body synthesis and Cholesterol synthesis

Question 9

What is the rate limiting step of Ketone Biosynthesis?

Answer 9

Formation of HMG CoA from Acetyl CoA

Question 10

What is the difference between the first two steps of cholesterol and ketone bodies synthesis?

Answer 10

Site. Cholesterol occurs in the cytoplasm while Ketone Biosynthesis occurs in the Mitochondrial Matrix

Question 11

In what step is the first ketone body produced?

Answer 11

3rd Step: formation of Acetoacetate as HMG CoA is cleaved

Question 12

What is produced when HMG CoA is cleaved in the third step of Ketogenesis

Answer 12

Acetoacetate, Acetyl CoA

Question 13

Acetoacetate can be reduced further to produce what Ketone Body?

Answer 13

B-Hydroxybutyrate

Question 14

Succinyl CoA’s effect on HMG CoA synthase succinylation

Answer 14

inhibits HMG CoA synthase succinylation and decreases rate of ketogenesis

Question 15

Glucagon’s effect on Ketogenesis

Answer 15

deceases amount of succinyl CoA in mitochondrian, increases ketogenesis

Question 16

Starvation’s effect on ketogenesis

Answer 16

increase of levels of HMG CoA snythase and its mrRN, increases rate of ketogenesis

Question 17

Insulin’s effect on Ketogenesis

Answer 17

decreases both activity and mrRna of the enzyme and decreases rate of ketogenesis

Question 18

Ketone Bodies are metabolized by the mitochondria by what cells?

Answer 18

Extra hepatic cells: brain, skeletal and cardiac

Question 19

Which two of the ketone bodies can be oxidized to produce energy?

Answer 19

Acetoacetate and b-hydroxybutyrate

Question 20

In starvation state and diabetes mellitus, what is the effect on glucagon/insulin ratio, acetyl coa and ketogenesis

Answer 20

Increased production of acetyl coa -> increased rate of ketogenesis

Question 21

compromises LCFA oxidation resulting to hypoglycemia
Lipid accumulation within muscle with weakness
New born has inadequate biosynthesis and renal leakage

Answer 21

Carnitine Deficiency

Question 22

CPT deficiency in the liver

Answer 22

CPT1

Question 23

CPT deficiency in the skeletal muscles and liver

Answer 23

CPT 2

Question 24

Reduced LCFA oxidation, Hypoglycemia and Hypoketosis

Recurrent episodes of myoglobinurias precipitated by prolonged exercise or fasting

Answer 24

CPT Deficiency

Question 25

Accumulation of Phytanic acid due to a defect in alpha oxidation

Answer 25

Refsum’s disease

Question 26

caused by eating unripe akee fruit

Answer 26

Jamaican Vomiting Sickness

Question 27

inactivates medium and short chain acyl CoA dh

Answer 27

Hypoglycin

Question 28

Absence of peroxisomes

Answer 28

Zellweger’s cerebro hepatorenal syndrome

Question 29

Medium Chain Acyl DH (MCAD) deficiency

Answer 29

common inborn error of lipid metabolism
autosomal recessive disorder caused by the substitution of a T for an A in position 985 of the MCAD gene
Boxidation of LCFAs proceeds only up to MCFA