Flashcards
BMS07-1031- Energy Release from Fat
Cards in this deck (23)
- 1Why are triglycerides an efficient way to store energy?They are large and can compact energy as fat droplets
- 2In a triglyceride (eg. 18:1), what does each number indicate?18 single C-C bonds
1 C=C bond - 3What is the structure of a triglyceride?A glycerol attached to 3 fatty acids via an ester bond
- 4What is the purpose of the beta oxidation pathway? What does it produce?Break down fatty acids for energy
1. Fatty Acyl CoA (minus 2 Cs)
2. acetyl CoA
3. 1 NADH
4. 1 FADH2
5. ATP - 5What is the first step of beta oxidation? Is this reaction reversible?Fatty acid combines with CoASH to become Fatty acid-CoA
Uses ATP-->AMP+PPi
Irreversible - 6What happens to Fatty Acid-CoA to allow it to enter the Inner mitochondrial membrane? What enzyme catalyses this?Fatty acid attached to cartinine, transported past membrane via antiport translocase in exchange for cartinine
Palmitoyl Transferase I - 7What does palmitoyl Transferase II do?Reattach Fatty acid to CoASH once they are both in the mitochondrial matrix (past inner membrane)
- 8What occurs to Fatty Acid-CoA once it is inside the mit. membrane during Beta Oxidation? (4 steps)1. Oxidation of fatty acid CoA into Enoyl CoA
- FAD-->FADH2
- Acyl- CoA dehydrogenase
2. Hydration of Enoyl CoA into hydroxyacyl CoA
3. Oxidation of Hydroxyacyl CoA-->B-Ketoacyl
- NAD+-->NADH+H+
- Hydroxyacyl CoA Dehydrogenase
4. Cleavage of B-Ketoacyl+CoASH to Fatty acyl CoA (2 C less) and acetyl CoA (for TCA cycle)
- Ketoacyl-CoA thiolase - 9What does lipolysis do?Break down Triglycerol into fatty acids and glycerol so body can process it better
- 10What is lipase activated by? (2)Adrenaline
Glucagon - 11What does TAG lipase do? What about DAG lipase and MAG lipase?1. Breaks down Triacylglycerol to Diayclglyerol +fatty acid
2. Diayclglycerol to Monoacylglycerol +fatty acid
3. Monoacylglycerol to glycerol - 12What happens to fatty acids from lipolysis?Bind to albumin in plasma because not very soluble, transported for use
- 13What happens to glycerol from lipolysis?1. Diffuses into tissues where it enters glycolysis to become pyruvate, then into TCA cycle for oxidation to CO2
2. In starvation/ the liver, becomes DHAP where it can enter become glucose via gluconeogenesis (reverse glycolysis) - 14What is ketogenesis?The breakdown of ketone bodies as the body's main energy source
- 15When does ketogenesis occur?Starvation/ diabietes
- 16Where does lipolysis happen in a cell?In the cytosol
- 17A fatty acid with 16 C will go through how many cycles of the B oxidation and produce how much NADH/FADH2/Acetyl CoA?7 times
7 of NADH/FADH2
8 Acetyl CoA - 18How are odd numbered fats metabolised?C15-->C13-->C11...C3
Then become succinyl CoA for TCA cycle - 19What happens to excess acetyl CoA produced as a result of high fatty acid oxidation during starvation/diabetes?Turned to ketone bodies bc TCA cycle can't keep up
- 20Why can the brain not use fatty acids? What does it use as emergency fuel instead?The blood brain barrier
Ketone bodies - 21How are ketone bodies used for energy? Which cells cannot use ketone bodies for energy? Why?1. Turned back to Acetyl CoA
/Succinate for the TCA cycle
- Liver cannot use ketone bodies bc lack enzyme to convert them into Acetyl CoA
- RBC cannot use fatty acids OR ketone bodies bc no mitochondria for TCA/B-oxidation - 22The brain can use... but not ... while RBCs cannot use eitherKetone bodies
Fatty acid
RBCs must use glucose - 23What is allosteric control of fatty acid oxidation? (2)1. Rise in NADH+H+ in comparson to NAD+ or acetyl CoA to CoA inhibits it
2. Rise in Malonyl-CoA from TCA cycle also inhibits it
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- Description
- importance of triglyceride fat for long term fuel storage. role of adipose tissue lipase in breakdown of triglyceride to fatty acids/ glycerol. how fatty acids are activated to CoA esters, and how they transported to mitochondria w/carnitine shuttle system. enzyme reactions of the β-oxidation pathway that yield acetyl-CoA, NADH and FADH2. factors regulating fatty acid oxidation. Outline how odd-numbered carbon-chain fatty acids are metabolised ketone bodies+ketogenesis in starvation
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- Evian Chai
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