KETONE METAB Flashcards

1
Q

Three kinds of ketone bodies

A

acetoacetate, b-hydroxybutyrate and acetone

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2
Q

Site of Ketogenesis

A

mitochondrial matrix of the liver

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3
Q

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

A

2 molecules of Acetyl CoA

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4
Q

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

A

acetoacetyl CoA via HMG CoA synthase

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5
Q

Where is HMG CoA Synthase only present in?

A

Mitochondrial matrix of the liver

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6
Q

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

A

HMG CoA?

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7
Q

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

A

HMG CoA

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8
Q

HMG CoA is common to what two pathways?

A

Ketone Body synthesis and Cholesterol synthesis

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9
Q

What is the rate limiting step of Ketone Biosynthesis?

A

Formation of HMG CoA from Acetyl CoA

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10
Q

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

A

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

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11
Q

In what step is the first ketone body produced?

A

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

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12
Q

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

A

Acetoacetate, Acetyl CoA

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13
Q

Acetoacetate can be reduced further to produce what Ketone Body?

A

B-Hydroxybutyrate

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14
Q

Succinyl CoA’s effect on HMG CoA synthase succinylation

A

inhibits HMG CoA synthase succinylation and decreases rate of ketogenesis

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15
Q

Glucagon’s effect on Ketogenesis

A

deceases amount of succinyl CoA in mitochondrian, increases ketogenesis

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16
Q

Starvation’s effect on ketogenesis

A

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

17
Q

Insulin’s effect on Ketogenesis

A

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

18
Q

Ketone Bodies are metabolized by the mitochondria by what cells?

A

Extra hepatic cells: brain, skeletal and cardiac

19
Q

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

A

Acetoacetate and b-hydroxybutyrate

20
Q

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

A

Increased production of acetyl coa -> increased rate of ketogenesis

21
Q

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

A

Carnitine Deficiency

22
Q

CPT deficiency in the liver

23
Q

CPT deficiency in the skeletal muscles and liver

24
Q

Reduced LCFA oxidation, Hypoglycemia and Hypoketosis

Recurrent episodes of myoglobinurias precipitated by prolonged exercise or fasting

A

CPT Deficiency

25
Accumulation of Phytanic acid due to a defect in alpha oxidation
Refsum's disease
26
caused by eating unripe akee fruit
Jamaican Vomiting Sickness
27
inactivates medium and short chain acyl CoA dh
Hypoglycin
28
Absence of peroxisomes
Zellweger's cerebro hepatorenal syndrome
29
Medium Chain Acyl DH (MCAD) deficiency
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