Fatty acid synthesis and catabolism

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  • Created by: kay
  • Created on: 28-05-19 12:28
Where does FA synthesis occur?
Cytosol
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Why does the biotin carrier protein on acetyl-CoA carboxylase flip?
So CO2 is on the transcarboxylase side
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At the start of FA synthesis, what parts of fatty acid synthase are malonyl-CoA and Acetyl-CoA bound to>?
Malonyl-CoA: ACP (acyl carrier protein) and acetyl-CoA: KS
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What are the 4 steps for FA synthesis?
Condensdation, reduction, dehydration and reduction
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What happens during condensation for FA synthesis?
CO2 is removed from malonyl-CoA
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What happens during the first reduction for FA synthesis? What is produced/used?
Beta carbon turned into alcohol, NADPH->NADP+, 1 ATP used
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What happens during dehydration for FA synthesis?
Double bond formed, H2O released
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What happens during the second reduction for FA synthesis? What is formed/used?
Double bond broken, chain lengthened by 2C, NADPH->NADP+, 1 ATP used
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At the end of FA synthesis cycle, what subparts of fatty acid synthase is the 4C chain passed from and to?
ACP to KS
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What happens to FA synthesis during a high blood sugar? Why?
Activation. Insulin leads to a phosphate being removed from acetyl CoA carboxylase which activates it to convert acetyl CoA to malonyl CoA. Malonyl CoA inhbiits carnitine acyl-transferase I moving 14C chains into the mitochondria for beta oxidation
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What happens when there is a high level of citrate?
It's converted out of mitochondira, actiavtes acetyl CoA carboxylase and converted to acetyl CoA
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What happens to FA synthesis during low blood sugar? Why?
Inhibition. Glucagon produces PKA which adds a phosphate to acetyl CoA carboxylase (inactivating it) and carnitine acyl-tranferase I is not inhibited (beta oxidation occurs)
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What happens when there is a high level of adrenaline? Why?
Inhibition/ Acetyl COA is needed for ATP, adrenaline adds a phosphate to acetyl CoA carboxylase inactivating it
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What are the 2 methods for producing other FA's from palmitate?
Add a double bond (desaturation) at position 9 or before. Or add more carbons (elongation)
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What are chymicrons made up of?
Triglycerides, cholesterol and alipoproteins
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What is the role of apoC-II?
Activates lipoprotein lipase to convert triglcerides into fatty acids and glycerol so they can enter the cell
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When there is low blood sugar and glucagon is released, what does it do?
Glucagon binds to receptors, forming cyclic AMP
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What is the role of cyclic AMP?
Activates protein kinase A
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What is the role of Protein kinase A?
Phosphorylates hormone sensitive lipase and perillipin
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What ist he role of hormone sensitive lipase?
Docks onto the surface of the lipid droplet and breaks down diglycerides into monoglycerides
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What is the role of perilipin?
DIssociates from CGI so CGI can interact with adipose triglycerol lipase
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What does adipose triglycerol lipase do?
Breaks down triglcerides into diglycerides
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What is the role of monoacylglycerol lipase?
Breaks down monoglycerides into fatty acids
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How are fatty acids transported in blood?
Bound to albumin
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In the carnitine shuttle, what does acyl-CoA synthases do?
Attaches CoA to fatty acids to form fatty acyl CoA
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In the carnitine shuttle, what does carnitine do?
Attaches to fatty acyl CoA to form a fatty acyl-carnitine ester
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In the carnitine shuttle, what does carnitine acyltransferase II do?
Transfers the fatty acyl to CoA
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What are the 4 steps in beta oxidation?
Dehydrogenation, hydrogenation, dehydrogenation 2 and removal of 1st acetyl-CoA
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In beta oxidation, what happens during the first dehydrogenation?
Fatty acid acyl CoA is converted to trans-enoyl-CoA by acyl-CoA dehydrogenase, creating a double bond and producing FADH2
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In beta oxidation, what happens during the hydrogenation step?
Trans-enoyl-CoA is converted to L-hydroxy-acyl-CoA by enoyl-CoA hydratase
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In beta oxidation, what happens during the second dehydrogneation step?
L-hydroxy-acyl-CoA is converted to beta-ketoacyl-CoA by hydroxyacyl CoA dehydrogenase, producing NADH
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In beta oxidation, what enzyme removes the 1st acetyl-CoA?
Thiolase (acyl CoA acetyl transferase)
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If beta oxidation of a 20 carbon sugar occured, how much total yield of ATP would there be?
136 ATP (9X4 = 36, 10X10 = 100)
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What happens when a cis C=C is reached during beta oxidation?
Enoyl-CoA isomerase converts cis to trans before step 2 of beta oxidation occurs
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Other cards in this set

Card 2

Front

Why does the biotin carrier protein on acetyl-CoA carboxylase flip?

Back

So CO2 is on the transcarboxylase side

Card 3

Front

At the start of FA synthesis, what parts of fatty acid synthase are malonyl-CoA and Acetyl-CoA bound to>?

Back

Preview of the front of card 3

Card 4

Front

What are the 4 steps for FA synthesis?

Back

Preview of the front of card 4

Card 5

Front

What happens during condensation for FA synthesis?

Back

Preview of the front of card 5
View more cards

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