Overview of Lipid Biochemistry

Question 1

When insulin is low and counter-regulatory hormones are high, triglyceride that has been stored in adipose tissue is broken down by the enzyme: ______

Answer 1

hormone sensitive lipase.

Question 2

A fatty acid that has entered the cytosol of a liver cell must gain access to the mitochondria to be oxidized. To do this, the fatty acid must first be converted to an acyl-carnitine which is then transported into the mitochondria by ______.This is the rate limiting step in the pathway of fatty acid oxidation

Answer 2

carnitine palmitoyl transferase 1 (CPT1, sometimes referred to as carnitine acyltransferase 1).

Question 3

The rate limiting step in ketogenesis is the synthesis of hydroxyl methylglutaryl CoA by ________

Answer 3

HMG CoA synthase

Question 4

Ketogenesis occurs in the _______ .

Answer 4

mitochondria

Question 5

Some cholesterol comes from the diet, but it can also be synthesized from acetyl CoA through the formation of _______. The rate limiting step in this pathway is HMG-CoA reductase. This reaction occurs in the cytosol and uses ______ for energy

Answer 5

hydroxymethyl glutaryl CoA,

NADPH

Question 6

describe phospholipids

Answer 6

specialized lipids that have a glycerol backbone and a PO4 group attached to one of the positions of the glycerol backbone.

Question 7

describe sphingolipids

Answer 7

Are built on a ceramide backbone. The ceramide backbone is unique because it is derived in part from an amino acid (serine) and so contains a nitrogen atom

Question 8

Describe glycosphingolipids

Answer 8

glycosphingolipids have a ceramide backbone, but also have sugar residues attached to the “head group

Question 9

what are the 3 lipoprotein pathways:

Answer 9

1. The dietary fat pathway or Chylomicron pathway in which triglyceride rich particles deliver dietary fat to skeletal muscle and adipose tissue. 2. The VLDL pathway by which triglyceride derived from the liver is delivered to skeletal muscle and adipose tissue and 3. The HDL pathway that largely functions as a reservoir and transport system for a variety of lipids including cholesterol.