University:
York University
Course:
BIOL 2020 | Biochemistry
Academic year:

2023
Views:

240

Pages:

3
Author:

Nick T.

In Class Notes 4/11/23 Triacylglycerols (TAG) - dietary fat Lipid Fatty Acid 1 Fat Triglycerides Steroid Cholesterol Triacylglycerols Fatty Acid Metabolism Lipids need transport molecule b/ they're hydrophobic Metabolism of Triglycerides Storage * Mobilization B-Oxidation Ketogenesis Lipogenesis Fatty Acid enters Cytosol of cell that needs energy... Activation Fatty acid is activated by addition of Coenzyme A Cost equivalent of 2 ATP Transport Fatty acid transported into mitochondrial matrix Carnitine moves fatty acid across membrane Oxidation the fatty acid-SCoA is oxidized by enzymes "Oxidation occurs by B-oxidation four reactions making up oxidation is oxidation of B-Carbon to the ester link Protein kinase activates Hormone Sensitive Lipase (HSL) removes fatty acids from triglycerides FAD removes hydrogen forms C=C Hydration water adds to new double band Secondary alcohol with OH on B carbon NAD oxidizes B-OH group to a Ketone Acetyl group is removed Why make (l-hydroxybutyrate or acetone? Acetoacetate is a relatively strong acid High concentrations of acetoacetate (ketosis) can lower blood pH (ketoacidosis) l-hydroxybutyrate is a weaker acid, so its effect on blood pH is much less Acetone is not acidic But it cannot be used as fuel Fatty Acid Oxidation β-Oxidation Pathway purpose: Oxidize Fatty acids "Cuts" fatty acids into 2-carbon Acetyl-CoA starting Materials: Fatty Acid-SCoA Free CoA -NAD -FAD products: Acetyl-CoA NADH, FADH2 Total Energy Production "One cycle of β-oxidation produces: 1 NADH 1 FADH2 Leads to total of 5 ATPs per cycle "In the Citric acid Cycle, each Acetyl-CoA produces: 3 NADH 1 FADH2 1 GTP Leads to total of 12 ATPs per Acetyl-CoA Ketogenesis occurs at a higher rate when... too much Ac-CoA Low glucose Low insulin CAC runs low Too much acetyl-SCoA for Citric acid Cycle to process, produces Ketone Bodies Ketone Bodies Compounds produced in the liver that can be used as fuel by muscle & brain cells Ketogenesis Synthesis of ketone bodies from acetyl-SCoA