Lecture 16 biochem

Flashcards on Lipid Metabolism

What molecules are formed during complete hydrolysis of a triacylglycerol?

A glycerol molecule and 3 fatty acids.

Where does the digestion of triacylglycerols primarily begin?

Small intestine.

What is the role of bile in the digestion of fats?

Solubilizes fat droplets.

What enzymes primarily hydrolyze TAGs in the small intestine?

Pancreatic lipases.

What are chylomicrons?

Transport vehicles for TAGs from intestinal cells to the bloodstream.

What enzyme mediates the hydrolysis of TAGs in the bloodstream?

Lipoprotein lipases.

Where are TAGs primarily stored in the body?

Adipose cells.

Name hormones that regulate TAG metabolism.

Insulin, glucagon, and epinephrine.

What process is described as the hydrolysis of TAGs stored in adipose cells followed by the release into the bloodstream?

Triacylglycerol Mobilization.

What are the products of complete TAG hydrolysis?

Glycerol and Fatty Acids.

What are the two steps involved in glycerol metabolism?

Phosphorylation and oxidation.

What enzyme catalyzes the phosphorylation of glycerol?

Glycerol kinase.

What enzyme catalyzes the oxidation of glycerol 3-phosphate?

Glycerol 3-phosphate dehydrogenase.

What is the product of glycerol oxidation?

Dihydroxyacetone phosphate.

In fatty acid oxidation, what is the initial step that expends energy?

Activation.

What molecule is fatty acid transferred to for transport into the mitochondrial matrix?

Carnitine.

What is the main process of fatty acid oxidation called?

β-oxidation.

What molecule is cleaved off during each round of β-oxidation?

Acetyl CoA.

What are the four reactions in the β-oxidation sequence?

Dehydrogenation, hydration, dehydrogenation, and thiolysis.

What enzyme catalyzes the first dehydrogenation step in β-oxidation?

Acyl CoA dehydrogenase.

What enzyme catalyzes the hydration step in β-oxidation?

Enoyl CoA hydratase.

What enzyme catalyzes the second dehydrogenation step in β-oxidation?

β-hydroxy CoA dehydrogenase.

What enzyme catalyzes the thiolysis step in β-oxidation?

Thiolase.

How many turns are used during 18 carbon fatty acid oxidation?

8.

What additional steps are required for the oxidation of unsaturated fatty acids?

Isomerization or epimerization.

What is the ATP yield from one acetyl CoA molecule in the citric acid cycle?

10 ATP.

Which fuel source does skeletal muscle prefer when active?

Glucose/glycogen.

Which fuel source does cardiac tissue prefer?

Fatty acids and ketone bodies.

What are the three ketone bodies produced during ketogenesis?

Acetoacetate, D-β-hydroxybutyrate, and acetone.

Where does ketogenesis primarily occur?

Liver mitochondria.