BMS07-1031- Energy Release from Fat

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
Evian Chai
Flashcards by Evian Chai, updated more than 1 year ago
Evian Chai
Created by Evian Chai over 4 years ago
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Resource summary

Question Answer
Why are triglycerides an efficient way to store energy? They are large and can compact energy as fat droplets
In a triglyceride (eg. 18:1), what does each number indicate? 18 single C-C bonds 1 C=C bond
What is the structure of a triglyceride? A glycerol attached to 3 fatty acids via an ester bond
What 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
What 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
What 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
What does palmitoyl Transferase II do? Reattach Fatty acid to CoASH once they are both in the mitochondrial matrix (past inner membrane)
What 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
What does lipolysis do? Break down Triglycerol into fatty acids and glycerol so body can process it better
What is lipase activated by? (2) Adrenaline Glucagon
What 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
What happens to fatty acids from lipolysis? Bind to albumin in plasma because not very soluble, transported for use
What 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)
What is ketogenesis? The breakdown of ketone bodies as the body's main energy source
When does ketogenesis occur? Starvation/ diabietes
Where does lipolysis happen in a cell? In the cytosol
A 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
How are odd numbered fats metabolised? C15-->C13-->C11...C3 Then become succinyl CoA for TCA cycle
What 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
Why can the brain not use fatty acids? What does it use as emergency fuel instead? The blood brain barrier Ketone bodies
How 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
The brain can use... but not ... while RBCs cannot use either Ketone bodies Fatty acid RBCs must use glucose
What 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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