22087404
Description
Flashcards by Evian Chai, updated more than 1 year ago
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Created by Evian Chai
over 4 years ago
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| 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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