Beta Oxidation
Upon entering the cell, fatty acids are activated by CoA in an irreversible reaction catalyzed by ____ and requires the equivalent of 2 ATP molecules.
acyl-CoA synthetase
The key regulatory enzyme in the first stage of cholesterol synthesis is _______ and is allosterically inhibited by cholesterol.
HMG-CoA Reductase
Fatty acid synthesis occurs in the _____ and requires acetyl-CoA which is produced in the mitochondria.
cytosol
Three ketones, acetoacetate, _______, and acetone are formed in the liver in the mitochondrial matrix.
beta-hydroxybutyrate
Triglyceride (TG) digestion starts in the mouth with lingual lipase that cleaves ester or SN3 bonds between glycerol and fatty acids in MCT and SCT creating diacylglycerides and fatty acids. This digestion process continues in the stomach with ______.
gastric lipase
A highly regulated step in fatty acid oxidation is the transfer of the acyl CoA fatty acid to carnitine by ______ whereby it is transferred into the inner membrane space of the mitochondria.
carnitine acyltransferase 1
Cholesterol is endogenously produced primarily by the liver (20%) and other peripheral tissues, the _____, being the most active.
intestine
Acetyl-CoA is transferred to the cytosol via citrate, which transverses through the mitochondrial membrane and is broken down into _____ and acetyl-CoA.
oxaloacetate
Peripheral tissues can convert ketones back to _____ to be used as fuel in the TCA cycle.
acetyl CoA
In the small intestine, bile from the gallbladder and pancreatic _____ from the pancreas is needed for continued digestion.
lipase
The fatty acyl carnitine moves through a transporter into the matrix and then the _____ is removed by the enzyme carnitine acyltransferase II.
carnitine
Dietary cholesterol inhibits cholesterol synthesis in the _____, but not other tissues.
liver
The first regulated enzyme in fatty acid synthesis is acetyl-CoA carboxylase which catalyzes the conversion of acetyl-CoA to _____ and requires biotin as a coenzyme and ATP.
malonyl-CoA
Ketones are produced by the liver in situations of high fatty acid oxidation combined with low _____ intake, seen in starvation, uncontrolled diabetes, or a very low ______ diet.
carbohydrate
Bile is necessary for the solublization of LCT to form micelles so pancreatic lipase can cleave the first and third fatty acid from the TG to form _____ and fatty acids.
monoacylglycerides
Long chain fatty acids undergo beta oxidation in the _____ of the mitochondria.
matrix
Cholesterol activates acyl-CoA: cholesteryl acyl transferase (ACAT) to increase the stored pool of cholesterol _____ in the cell.
esters
Fatty acid synthesis is catalyzed by a fatty acid synthase system that contain two key components: acyl carrier protein (ACP) and the _____ enzyme.
condensing
In these situations, acetyl-CoA is not able to enter the TCA cycle without adequate _____ and, thus, is converted to ketones.
oxaloacetate
_____ are able to penetrate the water layer of the enterocyte to deliver digested monoacylglycerides, fatty acids and cholesterol to the enterocyte to be absorbed by passive or facilitative diffusion.
Micelles
The beta oxidation pathway consists of four enzymes that catalyze in the sequential removal of acetyl-CoA until the entire fatty acid has been broken down into acetyl-CoA molecules. FADH2 and ____ are produced in this process.
NADH
Cholesterol also reduces the _____ receptor expression and, therefore, surface expression.
LDL
Malonyl-CoA is loaded onto the ACP portion of the enzyme and acetyl-CoA is loaded to the condensing enzyme, both losing CoA. In a series of four reactions, acetyl-CoA is continually added to a growing fatty acid chain until _____ (16:0) is formed.
palmitate
A condition of high circulating levels of ketones is called _____ and can cause acid-base imbalance.
ketosis
TGs are reformed and packaged into _____ that are transported into the lymphatic system and then to the bloodstream to deliver TG to the body tissues via lipoprotein lipase.
chylomicrons