Fatty Acid synthesis
Each of the following metabolic intermediates is a precursor to one or more of the nonessential amino acids except
Except--> Fumarate Is an intermediate--> -Alpha ketogluterate -oxaloacetate -3-phosphoglycerate -pyruvate
Coq
(ALL OF THE ABOVE) -Is an isoprene synthesized from an intermediate of the cholesterol synthesis pathway. -Is a component of the Electron transport chain -Undergoes reversible oxidation and reduction
The NAPDH used in fatty acid synthesis is generate by
- The pentose phosphate pathway -Malic enzyme (A& C on test)
The reciprocal control of Beta- oxidation and fatty acid biosynthesis involves which enzymes and which allosteric effectors?
-Malonyl- CoA the active intermediate of fatty acid biosynthesis allosterically inhibits carnitine acyltransferase I of Beta- Oxidation. - Fatty acyl- CoA's the active form of fatty acids for Beta oxidation- allosterically inhibits acetyl- CoA carboxylase of fatty acid biosynthesis
Which of the following statements regarding fatty acid biosynthesis is FALSE?
False--> Fatty acids are synthesized three carbon atoms at a time from malonyl- CoA (really 2) True--> -The CO2 used to activate the acetly- CoA to malonyl-CoA -The growing fatty acid is carreid from enzyme active site to enzyme active site covalently coupled to acyl carrier protein -after each cycle the the pathway the growing fatty acid is transferred from the acyl carrier protein to a -SH in the active site of Beta- Ketoacyl ACP synthase
(amino acid question on 2012) The common features of catabolism of all amino acids include
removal of the amine group and conversion of the carbon skeleton intermediate that can enter metabolism
Fatty acids (fatty acyl CoA's) activated in the cytoplasm cannot cross into the mitochondrial matrix until
they are transferred to a carrier molecule of caritine
The animal fatty acid synthase is a single multifunctional polypetide able to carry out the six reactions of the pathway. Which of the following is an advantage of this arrangement over the production of six individual enzymes
Dilution of the intermediates in the pathway is minimized
The coenzymes used in fatty acid synthesis is(are) ____ and it(they) is(are) synthesized primarily by the _________ pathway.
NADPH; Pentose Phosphate pathway
Which coenzyme form is the reducing agent for fatty acid biosynthesis
NAPDH
(amino acid question on 2012) Four of the nutritionally essential amino acids for adult humans are
leucine, lysine, threonine, and histidine
An animal volunteer is feed radioactive serine. After several days the animal is sacrificed and cellular components isolate and purified. Where would the radioactive label from serine not be found
Linolate
The rate limiting step in fatty acid synthesis is catalyzed by
Acetyl-CoA carboxylase
The glycerol necessary for the synthesis of triacylyglycerols and phosphoglycerides is obtained from
Dihydroxyacetone phosphate generated in glycolysis
Which of the following statements regarding fatty acid biosynthesis is false
False--> The CO2 used to activate the acetate group to malonyl is incorporated into the fatty acid and becomes part of the final product True--> -The growing fatty acid is carried from enzyme active site to enzyme active site coupled to acyl carrier protein -After each cycle through the pathway growing fatty acid is transferred from the acyl carrier protein to the Beta- Ketoacyl ACP synthase -Two reduction steps occur during the process of fatty acid biosynthesis -Fatty acids are synthesized two carbons at a time
Acyl carrier protein is used during
Fatty acid biosynthesis
Which of the following metabolic pathways does NOT require NAD+ or NADH
Fatty acid biosynthesis (NADP+ and NADPH)
Regulation of fatty acid synthesis in humans is affected by all of the following except
Insulin maintains acetyl-CoA carboxylase in the inactive form
Which of the following sequences of events is correct for the synthesis of fatty acids
Loading, condensation, reduction, dehydration, reduction, transfer
Which of the these statements about the regulation of cholesterol synthesis is not true
Not true-->Cholesterol is synthesized primarily when the cell is energy poor True--> -High cholesterol inhibits the synthesis of HMG- CoA reductase. -Failure to regulate cholesterol synthesis predisposes humans to atherosclerosis -Cholesterol acquired in the diet will inhibit the synthesis of cholesterol in the liver -Cholesterol allosterically inhibits HMG-CoA reductase
The reason saturated acyl residues generally occupy the 1 position and unsaturated acyl residues the 1 position of triacylglycerols and phospholipids is that:
The two acyl transferase involved in phosphatidate biosynthesis exhibit different specificities toward the saturated and unsaturated acyl-CoA residues that serve as substrates
What is the function of malonyl ACP in the biosynthesis of fatty acids
To add two- carbon units to the growing fatty acid chain
The cholesterol biosynthesis pathway is the source of isoprenes for the synthesis of CoQ
YES
What compound serves as the starting material for the biosynthesis of fatty acids and is also key intermediate in fatty acid metabolism
acetyl- CoA
The covalent attachment of CoA to a fatty acid functions
activates a fatty acid for metabolism
During fatty acid biosynthesis, to what substance are the activated intermediates bound
acyl carrier protein
(Found an amino acid question on 2012) In the synthesis of nonessential amino acids in humans,
asparagine is made from asparatate by an amid transferase reaction
In a fatty acid which carbon is atom is the beta carbon
carbon 3
Where in the cell are the enzymes responsible for fatty acid biosynthesis located
cytoplasm
The least likely source of acetyl-CoA for fatty acid biosynthesis is
fatty acids
Which of the following products results from the action of lipase on triacylglycerols
fatty acids and glycerol
The most likely source of acetyl- CoA for fatty acid biosynthesis is
glucose
(amino acid question on 2012) The conversion of nitrogen derivatives to urea takes place in the
liver
Triacylglycerols and phosphoglycerides are synthesized from a common intermediate. This common intermediate is
phosphatidate
Triacylglycerols and phosphoglycerides are synthesized from a common intermediate. This common intermediate is
phosphitidate
