Y1S2 005 III Biochem Hormone Regulation of Metabolic Energy Release

What is the result of glucagon binding to its cell-surface receptor?

Inhibition of hormone-sensitive lipase
Release of glycerol
Activation of adenylate cyclase (correct)
Phosphorylation of diacylglycerol lipase

What is the substrate for monoacylglycerol lipase?

Triacylglycerols
Monoacylglycerols (correct)
Fatty acids
Diacylglycerols

What is the role of PKA in the release of fatty acids?

Phosphorylation of diacylglycerol lipase
Inhibition of adenylate cyclase
Phosphorylation and activation of hormone-sensitive lipase (correct)
Release of glucagon

What is the net result of the action of hormone-sensitive lipase and other enzymes on triacylglycerols?

Three moles of free fatty acid and one mole of glycerol (A) Signup and view all the answers

What is the function of hormone-sensitive lipase?

Hydrolysis of fatty acids from triacylglycerols (C) Signup and view all the answers

What is the result of the activation of adenylate cyclase?

Increase in cAMP (B) Signup and view all the answers

What is the primary function of enoyl CoA isomerase in β-oxidation?

To move the naturally occurring cis- bond to the trans- bond (A) Signup and view all the answers

What is the consequence of carnitine deficiency in newborns?

Inability to transport fatty acids into the mitochondria for oxidation (B) Signup and view all the answers

Which of the following is a symptom of Carnitine Palmitoyltransferase II (CPT II) deficiency?

Recurrent muscle pain and fatigue (D) Signup and view all the answers

What is the primary organ affected by Carnitine Palmitoyltransferase I (CPT I) deficiency?

Liver (B) Signup and view all the answers

What is the treatment for carnitine deficiency?

Oral administration of carnitine (D) Signup and view all the answers

What is the primary difference between the oxidation of saturated and unsaturated fatty acids?

Unsaturated fatty acids require enoyl CoA isomerase (A) Signup and view all the answers

What is the role of carnitinepalmitoyltransferase I in the transport of fatty acids into the mitochondria?

To exchange CoA for carnitine in the cytoplasm (B) Signup and view all the answers

What is the product of the first step in β-oxidation?

Trans-Δ2-enoyl-CoA (A) Signup and view all the answers

What is the enzyme responsible for the hydration of the double bond in the second step of β-oxidation?

Enoyl-CoA hydratase (B) Signup and view all the answers

What is the product of the third step in β-oxidation?

A ketone (B) Signup and view all the answers

What is the final product of β-oxidation?

Acyl-CoA and a long chain fatty acyl CoA (B) Signup and view all the answers

What is the role of β-ketoacyl-CoA thiolase in β-oxidation?

To catalyze the thiolytic cleavage of the thioester (C) Signup and view all the answers

What is the final product of the β-oxidation of fatty acids with an odd number of carbon atoms?

Succinyl-CoA units (B) Signup and view all the answers

Which enzyme is responsible for converting the D-isomer to the L-isomer in the β-oxidation of fatty acids with an odd number of carbons?

Methylmalonyl CoA racemase (B) Signup and view all the answers

What is the role of enoyl CoA isomerase in the β-oxidation of fatty acids with an odd number of carbons?

To convert cis double bonds to trans double bonds (A) Signup and view all the answers

What is the first step in the β-oxidation of fatty acids with an odd number of carbons?

Carboxylation by the biotin-dependent propionyl CoA carboxylase (C) Signup and view all the answers

What is the product of the ATP-dependent pathway that propionyl-CoA undergoes?

Succinyl-CoA (A) Signup and view all the answers

Why is enoyl CoA isomerase required in the β-oxidation of fatty acids with an odd number of carbons?

Because β-oxidation generates or requires pre-existing double bonds at even-numbered carbons (B) Signup and view all the answers

What is the effect of sulfonylurea drugs on carnitine acyltransferases?

They inhibit the enzyme (A) Signup and view all the answers

What is the most common form of acyl-CoA dehydrogenase deficiency?

Medium Chain Acyl CoA Dehydrogenase Deficiency (C) Signup and view all the answers

What is the diagnostic indicator of Medium Chain Acyl CoA Dehydrogenase Deficiency?

Excessive urinary excretion of medium-chain dicarboxylic acids (D) Signup and view all the answers

What is the primary cause of Refsum's disease?

Deficiency of the mitochondrial α-oxidizing enzyme (D) Signup and view all the answers

What is the primary treatment for Refsum's disease?

Restriction of dairy products and ruminant meat from the diet (B) Signup and view all the answers

What is the typical age range when symptoms of Medium Chain Acyl CoA Dehydrogenase Deficiency become apparent?

Early childhood (1-5 years) (A) Signup and view all the answers