Lecture 26 - Fatty acids as a fuel molecule #2 Flashcards
Do adipose tissues make lipoproteins?
NO
What does adipose lipase do?
cleaves TAGs to give
three FFAs and glycerol
Are free fatty acids polar or non-polar?
non-polar
Where can fatty acids come from?
- diet or the liver
- storage in adipose tissue
How is the delivery of fatty acids to tissues?
- Adipose lipase makes FFA + Glycerol by cleaving TAG
- FFA passively travel in blood
- FFA bind albumin
- Transported to tissues passively
When are fatty acids activated?
before B-oxidation
When does fatty acid activation occur before or after entering the mitochondria?
Before
How are fatty acids activated?
By the attachment of CoA to make fatty acyl-CoA
What energy is required to CoA?
hydrolysis of ATP to AMP (energy equivalent of 2 ATP)
Oxidation of fatty acids occurs in the?
mitochondrial matrix
Movement between the cytosol and matrix
requires?
two membranes to be crossed
How are fatty acids transported to the mitochondrial matrix?
- The fatty acyl-CoA must pass through two membranes
- Outer membrane: uses fatty acyl-CoA carrier
- Inner membrane: requires the conversion to fatty acyl-carnitine
The carnitine acyltransferase reaction?
- Exchanges CoA and carnitine on a fatty acid
- Reversible reaction
Where does B-oxidation occur?
In mitochondrial matrix
What fatty acids does B-oxidation use?
fatty acids with an even number of carbons that are saturated (no double bonds)
Is ATP produced during B-oxidation?
No, ATP is not directly made in β-oxidation
What is energy released during B-oxidation transfered to?
the coenzymes NAD and FAD
What happens to the carbon chain during B-oxidation?
Is cut into two pieces
What is the product of B-oxidation?
acetyl-CoA
What happens to acetyl CoA?
is further oxidised in the citric acid cycle
What are the 4 steps of B-oxidation?
- Oxidation
- Hydration
- Oxidation
- Cleavage
What happens during the first reaction of B-oxidation (oxidation)?
Fatty acyl-CoA is oxidised forming a double bond, the 2x H atoms form FADH2 from FAD (FAD -> FADH2)
What happens during the second reaction of B-oxidation (hydration)?
Fatty acyl-CoA is hydrated by the addition of H2O, this breaks the double bond and puts an OH on one carbon and H on the other
What happens during the third reaction of B-oxidation (oxidation)?
Fatty acyl-CoA is oxidised, the O of the OH loses its hydrogen forming a double bond, and the carbon bonded to the O loses its hydrogen. (NAD+ -> NADH + H+)
