Tricarboxylic Acid (TCA) Cycle Flashcards
What is the TCA cycle also known as?
Citric acid cycle
The TCA cycle connects the __ ___ to the electron transport/oxidative phosphorylation pathway in the generation of metabolic energy as ATP molecules
glycolysis pathway
What does the TCA cycle generate?
Metabolic energy as ATP molecules
The three linked pathways result in the production of ____ molecules of ATP per molecule of glucose
30-32
How many ATP/glucose are produced in glycolysis?
2 ATP/glucose
How many ATP/glucose are produced in the TCA cycle?
2 ATP/glucose
What is the total number of ATP/glucose produced via the three linked pathways?
30-32 ATP/glucose
What enters the TCA cycle?
Carbon
Carbon enters the TCA cycle as the two-carbon acetyl group of _____
acetyl-coenzyme A
The acetyl groups are derived from the ___ ___ ___ molecule
three-carbon pyruvate
What is the major product if glycolysis?
three-carbon pyruvate
What are the products of the TCA cycle?
2 ATP, CO2, NADH, and FADH2
2 pyruvate —-> acetyl-CoA
Glycolysis —-> TCA cycle
The glycolysis pathway is connected to the TCA cycle by the conversion of two of the three carbon atoms of ____ into the acetyl group of _____
pyruvate, acetyl-coenzyme A
What are the most important products of the TCA cycle?
NADH & FADH2
Protons and electrons connect & stimulate the next ____
Pathway, Oxidative electron transport phosphorylation
NADH binds to the ___ complex protein of the electron transport chain
first
FADH2 binds to the ___ complex protein of the electron transport chain
second
Protons are released into the ___ ___ of the cell
inter membrane space
The interaction of molecular oxygen with complex ___ leads to the production of H20
four
Complex four is stimulated by what reaction?
O2 from our lungs being converted into water
___ molecules are transported between complex 3 and 4
cytochrome c
NADH —-> NAD+ + ___ + ___
H+, 2e-
What two components are also involved in addition to oxygen to produce water?
protons and electrons
Coenzyme A contains pantothenic acid and the _____ ____
nucleoside adenosine
Coenzyme A bonds acetyl groups through the _____ group at the end of the molecule
sulfhydryl (-SH)
What enzyme converts pyruvate into acetyl coA?
pyruvate dehydrogenase
What is the active group of acetyl coA?
sulfhydryl
coenzymeA contains __ and __
pantothenic acid, adenosine
How does coenzyme A bind acetyl groups?
Through the sulfhydryl (SH) group at the end of the molecule
What two things occur when pyruvate is turned into acetyl coA?
O2 converts to CO2, NAD+ converts to NADH
Acetyl coA is a ___ carbon molecule
2
(1) what two things combine to create citrate?
oxaloacetate & acetyl -coA
(1) what is the short lived intermediate molecule produced during citrate synthesis?
citrate synthase
1 acetyl coA molecule produces ___ NADH molecule
1
How many CO2s are released per cycle?
2
How many FADH molecules are created per cycle?
1
One carbon of pyruvate is released in the form of ___ so that it can enter the cycle
CO2
What enzyme converts pyruvate into acetyl coA?
pyruvate dehydrogenase
What is the active group of acetyl coA?
sulfhydryl
coenzymeA contains ___ __ and ___
pantothenic acid, adenosine
(2) citrate is converted to isocitrate by ___
aconitase
(3) isocitrate is converted to alpha-ketoglutarate by
isocitrate dehydrogenase
(4) alpha-ketoglutarate is converted to succinylcholine coA by
alpha-ketoglutarate dehydrogenous
___ is released when isocitrate is converted to alpha-ketoglutarate
CO2
___ is released when alpha-ketoglutarate is converted to succinylcholine-coA
CO2
(5) succinylcholine coA is converted to succinate by
succinyl coA synthetase
(6) succinate coA is converted to fumarate by
succinate dehydrogenase
(7) fumarate is converted to malate by
fumarase
how many carbons are in oxaloacetate?
4
how many carbons are in citrate?
6
how many carbons are in isocitrate?
6
how many carbons are in alpha-ketoglutarate?
5
how many carbons are in succinylcholine coA?
4
how many carbons are in succinate?
4
how many carbons are in fumarate?
4
how many carbons are in malate?
4
What is released when oxaloacetate is converted into citrate?
coA (SH) , H2O
The reaction of oxaloacetate to citrate is a __ step reaction
2
The reaction of citrate to isocitrate is a __ step reaction
2
____ groups are lost in the form of CO2
carboxyl
What extra enzyme is seen during the conversion of succinylcholine coA to succinate and acts to convert ADP to ATP?
nucleoside diphosphate kinase
During what conversion is GTP produced from GDP
succinyl coA to succinate
During what conversion is FADH2 produced?
succinate to fumarate
The ____ ___ reaction produces FADH2
succinate dehydrogenase
What is unique about the enzyme succinate dehydrogenase?
it is an integral membrane protein of the inner mitochondrial membrane
Asparagine can be produced from what TCA molecule?
oxaloacetate
lysine, isoleucine, and methionine can be produced from what TCA molecule?
fumarate
Where are all of the enzymes besides succinate located in the TCA cycle?
Water soluble proteins in the mitochondrial matrix
acetyl coA is the precursor to what groups of molecules ?
fatty acids and steroids
Succinate is _____
hydrophobic
Uses of TCA cycle intermediates:
alpha-ketoglutarate
amino acids, nucleotides
Uses of TCA cycle intermediates:
fumarate
amino acids, nucleotides
Uses of TCA cycle intermediates:
oxaloacetate
amino acides, nucleotides, carbohydrates
Uses of TCA cycle intermediates:
acetyl coA
fatty acids, steroids
What molecules can synthesize from the TCA cycle?
amino acids, nucleotides, carbohydrates, fatty acids, steroids
Malate is converted to oxaloacetate is by
maltase dehydrogenase
pyruvate is the starting molecule for ___, ___, and ____
alanine, leucine and valine
