Catabolic Metabolism - Lipids, Triglycerides, Fatty Acids, and Ketone Bodies

Question 1

Identify examples of the major classes of lipids.

Answer 1

Steroids, Triacylglycerides, Phospholipids, Sphingolipid, Waxes

Question 2

Compare the physical properties of saturated and unsaturated fatty acids.

Answer 2

unsaturated fatty acids decrease the melting point of cell membranes

Question 3

Apply the different types of nomenclature to saturated and unsaturated fatty acids.

Answer 3

Unsaturated - “omega-x” x = number of carbons after the double bond at the end of the chaing

x:y = # of carbons:# of double bonds

Question 4

Describe how phospholipids and triacylglycerides are digested by pancreatic lipases and subsequently resynthesized prior to chylomicron mediated transport.

Answer 4

Fatty acids are broken down into monoglycerides by bile and pancreatic lipases. The monoglycerids are absorbed through the epithelial layer and are then resynthesized as triglycerides. Before leaving the cell, the fatty acids are coated with proteins and it becomes chylomicrons

Question 5

Describe the molecular events involved in mobilizing fatty acids from adipose tissue.

Answer 5

Hormone-sensitive lipase is acted by hormones. HSL then breaks down triaclyglycerides into free fatty acids which are then ferried by albumin to metabolic tissues. FFA are transported into the cell through fatty acid transporter where it metabolized

Question 6

Describe the hepatic anabolism of ketone bodies and their subsequent extrahepatic catabolism.

Answer 6

Acetyl CoA is turned into ketone bodies in the liver. (occurrence of ketone breath)

Ketone bodies are then turned back into Acetyle CoA in the muscle and incorporated into Kreb cycle

Question 7

Describe fatty acids transport into the mitochondria of hepatocytes and myocytes and their subsequent b-oxidation to acetyl CoA.

Answer 7

Fatty Acids (Fatty Acyl CoA Synthetase) - Fatty Acyl CoA
Carnitine is added to FA CoA by Carnitine Acyl Transferase I (CAT I) which is on the outer membrane of the mitochondria. Carnitine is removed from FA CoA by CAT II after it is shuttled into the mito matrix. 

Beta Oxidation
Acyl CoA oxidizes into Acetyl CoA with the production FADH2 and NADH