Module 7 Lipid Metabolism

cexapujo's version from 2015-05-31 02:16

Section 1

Question Answer
What is solubilization of dietary lipids?Emulsification
How is emulsification of dietary lipids accomplished?Via bile salts
Where are bile salts synthesized?Liver
Where are bile salts secreted?Gallbladder
Where are pancreatic lipases secreted from?Pancreas
What do pancreatic lipases do?degrade emulsified fats

Section 2

Question Answer
What are the primary sources of FAs for oxidation?Dietary and mobilization from stores
What is the stimulus to activate the mobilization of stored TAGs for use by peripheral tissues?Glucagon or Epinephrine
Is glucagon or epinephrine a stronger mobilizer?Epinephrine
What inhibits the mobilization of fat from adipose tissue most significantly?Insulin

Section 3

Question Answer
What catalyzes the activation (within the cytoplasm) of fatty acids?Fatty acyl-coA ligase ("acyl-coA synthetase")
Why is fatty acid oxidation termed B-oxidation?it occurs the sequential removal of 2-carbon units at the B-carbon position of the fatty acyl-coA molecule
What does each round of B-oxidation produce?one mole of NADH, one mole of FADH2, and one mole of acetyl-coA
Where does B-oxidation occur?In the cytosol (mitochondria)
What the B-oxidation require?The equivalent of 2 ATP molecules
Why is carnitine important in B-oxidation?Allows fatty acyl-coA to be transported into the mictochondria
Why is there a metabolic difference between the oxidation of saturated vs. unsaturated fats?Unsaturated fats produce less energy because there double bond has to be moved from cis to trans by enoyl-coA isomerase which required two ATP. Unsaturated fatty acids provide less energy because they are more highly reduced.
How does B-oxidation of odd-numbered fatty acids proceed?By the same reaction steps as even numbered until the final three carbons are reached
What are the final three carbons of odd numbered fatty acids called?propionyl coA
What is proprionoyl coa converted to in odd B-oxidation?succinyl coA through a multistep ATP-dependent pathway. Succinyl CoA can then enter the TCA cycle.
What does mutase require?Vitamin B12

Section 4

Question Answer
What is produced in large amounts during high rates of B-oxidation (primarily in the liver)?Acetyl-CoA
What is the result of Acetyl-CoA production exceeding the capacity of the TCA cycle?the synthesis of ketone bodies
What is the synthesis of ketone bodies called?Ketogenesis
What are the predominate ketone bodies in ketogenesis?Acetoacetate, B-hydroxybutyrate, and acetone
What happens to the production of B-hydroxybutyrate when glucagon in the liver is HIGH?The production of b-hydroxybutyrate increases
What happens when the last remnant of fat are oxidized?Heart and skeletal muscles will consume primarily ketone bodies to preserve glucose for use by the brain.
What does the oxidation of fats involve?the reduction of FADH+ and NAD

Section 5

Question Answer
Where does fatty acid synthesis occur?Cytoplasm
What does synthesis of fats involve?Oxidation of NADPH
What carrier molecule is involved in the transfer of acetyl coA from mitochondria to cytoplasm in FA synthesis?Citrate
What is the first committed step of fatty acid synthesis?Malonyl CoA
What enzyme catalyzes the first rxn in fatty acid synthesis?ACC- major site of regulation of FA synthesis
What is the primary fat produced in FA synthesis?palmitate

Section 6

Question Answer
What is the key regulatory site for B-oxidation?ACTI/II

Section 7

Question Answer
Where is the greatest proportion of cholesterol used?Bile acid synthesis
What lipoprotein transports cholesterol from the intestine to the liver?Chylomicron
What lipoprotein transports cholesterol from the liver to the muscle?VLDL
What lipoprotein transports cholesterol from the peripheral tissues to liver?HDL
What is the primary mechanism for controlling the level of cholesterol biosynthesis?HMG-CoA Reductase activity