FA catabolism and Beta oxidation Flashcards
Where do fatty acids (FA) come from? (3)
Diet
Lipid droplets in cells/seeds (TAGs)
Synthesis and transport to another organ
Fatty acid catabolism provides:
Reducing equivalents that produce ATP
Acetyl CoA that can
- be oxidized by CAC –> ATP
- Converted into ketone bodies
- be used for cholesterol biosynthesis
- act as a precursor to fatty acid
synthesis
What do Bile salts do? Where are they produced?
Bile salts produced in the liver, specifically the Gallbladder.
Bile salts emulsify dietary fats
Define amphipathic
a molecule, especially a protein, having both hydrophilic and hydrophobic parts
Can glycerol enter glycolysis? (T/F)
True
What are chylomicrons made of (4)
TAGs
Cholesterol
Apolipoproteins
Phospholipids
Where is Lipoprotein lipase found? What does it do?
Capillary, it breaks chylomicrons to release FA and glycerol in the blood. FA are then diffused into cells.
What cells/tissues take up FAs?
Adipose tissue: TAGs as storage
Muscle tissue: Oxidized for energy
Why do fats need something to help carry them through the blood stream?
Because they’re more hydrophobic than hydrophilic
What signals to the adipose tissue that energy/fats are required?
Hormones / hormone signal
Glucagon
What is a muscle cell called?
Myocyte
Where is FA targeted for oxidation?
Once it enters the mitochondria
When FAs leave an adipocyte and enter the blood stream, what transports them to a myocyte?
Serum Albumin
Where does Beta oxidation occur?
mitochondrial matrix
We can harvest 100% of TAGs energy (Remember, TAG = glycerol + FA). What percentage of energy comes from the FAs and what percent of energy comes from the Glycerol?
FAs yield 95% of energy from TAGs
Glycerol yields 5% of energy from TAGs (because it is converted back into glucose = glycolysis)
When moving fatty acyl-Coa into the mitochondria, what is the rate limiting step?
Transferal of fatty acyl coa to creatine
When is fatty acyl coA committed to beta oxidation?
Once it’s in the mitochondria
If you have a 16C FA, how many Acetyl CoA will you produce? How many beta oxidation will occur? How many ATP is yielded?
7 beta oxidations (16/2 - 1 = 7)
8 acetyl coA
28 ATP (4x7) from beta oxidation
+ 80 ATP (8x10) from CAC
What energy molecule(s) are produced from one round of beta oxidation? How much total ATP does this yield?
NADH(2.5 ATP) and FADH2 (1.5 ATP)
Total = 4 ATP
Why is it called beta oxidation?
because the beta carbon is continuously oxidized each step.
A hydration reaction occurs in beta oxidation (T/F)
True, this is how we can yield NADH
How much ATP does one Acetyl Coa yield from the CAC?
10 ATP (3 NADH, 1 FADH2, 1 GTP)
If 8 acetyl CoA are yielded from a 16C FA, how many ATP are yielded from CAC alone?
How many ATP produced by beta oxidation of the 16C FA and CAC together?
8 acetyl coA x 10 ATP = 80 ATP
16/2 - 1 = 7 beta oxidations 4 ATP x 7betaox = 28 ATP
Total: 28 + 80 = 108 ATP - 1 ATP from mitochondrial commitment = 107 total
How much ATP does one round of beta oxidation yield?
4 ATP (1 NADH, 1 FADH2)
