Fat Metabolism Flashcards
What does the presence of lots of malonyl coA indicate?
Fed state
How is citrate formed?
Oxloacetate + acetyl CoA
What does malonyl CoA do?
Inhibit carnatine transferase so fatty acid can’t be transported into the mitochondria for respiration
What causes fat to be taken up for storage?
Insulin
What do chylomicrons do?
Dietary TAG
What does HDL do?
Cholesterol is moved from the tissue to the liver
What does LDL do?
Move cholesterol to tissues
What does VLDL do?
Carries endogenous (bodily) TAG
What does HDL do?
Cholesterol leaves the tissue
Describe the structure of a lipid (4)
Apoprotein, phospholipids and cholesterol and then TAG and cholesterol esters
Why are lipoproteins used?
To carry insoluble fat
What makes up VLDL (3)
Apoproteins, TAG and polar lipids
What are apoproteins?
Proteins that can’t function alone
What is lipoprotein A?
LDL and apoprotein A
What is atherosclerosis?
Deposition of fat in arteries
What is a foam cell?
A cell that takes up cholesterol and fat that has built up
Describe the journey of HDL
Cholesterol leaves the tissue or smooth intestine binds to apoA and enters the liver
Describe the path of a chylomicron
TAG and apoB leave the small intestine and take apoE and apoC from HDL to form a chylomicron
It enters a capillary and lipoprotein lipase removes the TAG for storage leaving the remains to go into the liver
Describe the paths of VLDL and LDL
ApoB and TAG leave the liver and take ApoC and ApoE from HDL in the capillary and then lipoprotein lipase releases the FA for storage leaving a glycerol and intermediate density protein
That can either loose B100 to form HDL or loose apoE and apoC to form LDL which enters the liver to pick up TAG and form VLDL
Where do we get LDL?
We make it in the liver
What does LDL do?
Inhibit nucleic enzymes so they can’t make cholesterol or LDL receptor
What makes HMG CoA?
Acetyl CoA and acetoacetyl CoA
What do stations do?
Inhibit the enzyme that makes HMG CoA
When do we make cholesterol?
When we aren’t eating enough
How does coenzyme A form acetyl coA?
Add a COOH to it
What activates the enzyme lipase?
Adrenaline, low ATP and glucagon
How are TAG’s completely broken down?
Lipase remove 1 FA
DAG lipase removes another
MAG lipase removes another
How do FA travel in the blood?
Bound to albumin
What is the TAG’s remaining glycerol used for?
Diffuses into tissues to form pyruvate or glucose
When the body’s main fuel is fat what other process if also occurring and why?
Ketogenesis
There is too much acetyl coA so its converted to ketone bodies
How do we form fatty acyl coA?
FA + coA + ATP + fatty acyl coA synthetase
Describe beta oxidation
Fatty acyl coA is converted to enoyl coA
FAD to FADH2
Enoyl coA is converted to hydroxyacyl coA
Water is used
Hydroxyacyl coA is converted to keto acyl coA
NAD to NADH2
Keto acyl coA is converted to fatty acyl coA
Coenzyme A is used
Why may beta oxidation occur multiple times on the same compound?
If the chain is still very long
What do odd number chains form instead of acetyl coenzyme A?
Propionyl-coA
What happens when propionyl coA is made?
CO2 and ATP is added to convert it to methylmalonyl coA which is converted to succinyl coA which is then used in the krebs cycle
