Chapter 10: Carbohydrate Metabolism II: Aerobic Respiration Flashcards
What is the main function of the citric acid cycle?
- Oxidation of acetyl-CoA to CO2 and H2O
- producing NADH and FADH2
After glucose undergoes glycolysis, its product, ____________, enters the mitochondrion via active transport and is oxidized and decarboxylated. These reactions are catalyzed by what multienzyme complex?
pyruvate; pyruvate dehydrogenase complex
Pyruvate dehydrogenase complex is inhibited by what? What could caused this?
An accumulation of acetyl-CoA and NADH; can occur if ETC is not properly function or is inhibited
Coenzyme A is a ____________, which means it contains what functional group?
Thiol; -SH
When acetyl-CoA forms, it does so via covalent attachemnt of the ________ group to the -SH group, resulting in the formation of a ________________, which contains sulfur instead of the typical oxygen ester -OR.
acetyl; thioester
What are the 3 enzymes that are part of the pyruvate dehydrogenase complex?
- pyruvate dehydrogenase
- dihydrolipoyl transacetylase
- dihydrolipoyl dehydrogenase
When pyruvate is oxidized by pyruvate dehydrogenase (PDH), it yields ____, and the remaining 2-carbon molecule binds covalently to ____________ ________________. This is a coenzyme held by noncovalent interactions to PDH. ____ is also required.
CO2; thiamine pyrophosphate; Mg2+
The 2-carbon molecule bonded to TPP is oxidized and transferred to ________ acid, a coenzyme bonded to dihydrolipoyl transacetylase. Lipoic acid’s disulfide group acts as an oxidizing agent, creating the ________ group, which is now bonded to lipoic acid via ____________ linkage. Dihydrolipoyl transacetylase catalyzes the ____-____ interaction with the newly formed thioester link, causing transfer of an acetyl group to form ________-________.
lipoic; acetyl; thioester; CoA-SH, acetyl-CoA
Flavin adenine dinucleotide is used as a coenzyme in order to reoxidize lipoic acid, allowing lipoic acid to facilitate acetyl-CoA formation in future reactions. As lipoic acid is reoxidized, FAD is reduced to ________, which is later reoxidized to ____, while NAD+ is reduced to ____.
FADH2, FAD, NADH
Flavin adenine dinucleotide is used as a coenzyme in order to reoxidize lipoic acid, allowing lipoic acid to facilitate acetyl-CoA formation in future reactions. As lipoic acid is reoxidized, FAD is reduced to ________, which is later reoxidized to ____, while NAD+ is reduced to ____.
FADH2, FAD, NADH
Acetyl-CoA is best known as being generated by oxidative decarboxylation of ____________ in the ____________ pathway.
pyruvate; glycolysis
Acetyl-CoA can also be made during ________ ________ oxidation. A process called ____________ causes a thioester bond to form between carboxyl groups of fatty acids and CoA-SH.
fatty acid; activation
Because activated ________ ________-________ cannot cross the inner mitochondrial membrane, the fatty acyl group is transferred to ____________ via a trans-esterification reaction.
Once acyl- carnitine crosses the inner membrane, it transfers the fatty acyl group to a mitochondrial CoA-SH via another transesterification reaction. Carnitine’s main function is what?
fatty acyl-CoA; carnitine
Fnction is to carry acyl group from cytosolic CoA-SH to a mitochondrial CoA-SH; once acyl-CoA is in the matrix, beta-oxidation can occur
Certain ________ ________ can also be used to form acetyl-CoA. They have to lose their ________ group via transamination. Their carbon skeletons can then form ________ ________. This is why they are labeled “ketogenic.”
amino acids; amino; ketone bodies
Although acetyl CoA is typically used to produce ____________ when pyruvate dehydrogenase complex is inhibited, the reverse reaction can occur as well, and this produces?
ketones; acetylCoA
