Long Exam 2 Study Guide

Long Exam 2 Study Guide - Chapter 17 (Beta oxidation) Beta...

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Chapter 17 (Beta oxidation) Beta oxidation – the 4-step cycle that breaks down fatty acids into acetyl-coA and electrons for oxidation Triacyglycerol – glycerol backbone + 3 fatty acids Adipocyte – fat storing cell containing a single large droplet of lipid, pushing the mitrochondria, nucleus, and other organelles up against the edge of the cell Fatty acid – contains 95% of total TAG energy Glycerol – carbon backbone of the TAG, contains 5% of the total TAG energy Adipose tissue – fat-storing tissue - Cellular location of beta oxidation Beta oxidation occurs in the mitochondrial matrix. - Relationship between beta oxidation, citric acid cycle, and ETC Beta oxidation breaks down fatty acids into acetyl-coA while simultaneously giving off electrons to NADH. The acetyl-coA molecules are oxidized in the CAC to yield ATP, NADH, and FADH2. The NADH and FADH2 join the NADH produced in beta oxidation in the ETC for oxidative phosphorylation. - Properties of fats that make them good energy sources, and difficulties of digestion related to these same properties - Fat intake (as percentage of energy intake) in most industrialized countries vs. recommended intake - Role of fats in plants - Overview of fat ingestion, digestion, absorption In the small intestine, bile salts emulsify fats into mixed micelles so that more surface area is available to lipases. These lipases degrade TAGs into glycerols and fatty acids, both of which are taken up into intestinal cells and reconverted into TAGs. These TAGs become a part of chylomicrons (cholesterol + apolipoproteins). Chylomicrons transport TAGs into the blood. There, lipases are activated by the apoC-II lipoprotein in the chylomicrons, and they degrade TAGs (once again) into glycerols and fatty acids. Fatty acids then enter cells—either adipocytes or myocytes—and are either oxidized as fuel or reesterfied for storage. Glycerols are converted into glycerol-3-phosphate, then dihydroxyacetone-phosphate, and finally glyceraldehyde-3- phosphate by glycolysis. - Epinephrine/glucagon initiated reaction cascade resulting in fatty acid release Epinephrine or glucagon binds to an extracellular receptor, a part of a GCPR. The G protein is activated and moves to the adenyl cyclase, which is activated and thus converts ATP into cAMP. cAMP activates protein kinase, which in turn activates triacylglyercol lipase. This initiates the breakdown of stored TAGs in adipocytes. The fatty acids that are released move into the blood stream, carried by serum albumin, then enter myocytes for beta oxidation. - Carnitine-fatty acid transport into mitochondrial matrix (how, why) The carnitine shuttle exists in order to separate fatty acids for different purposes. In the mitochondrial intermembrane space, activated fatty acids are used for lipid biosynthesis. In the mitochondrial matrix, activated fatty acids’ fates are sealed for beta oxidation. The process begins with activated fatty acyl-coA being converted to fatty acyl-carnitine by carnitine
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This note was uploaded on 12/10/2011 for the course BCH 5045 taught by Professor Guy during the Fall '08 term at University of Florida.

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Long Exam 2 Study Guide - Chapter 17 (Beta oxidation) Beta...

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