Cellular Respiration Flashcards
Formula for Cellular Respiration
C6H126O + 6 O2 → CO2 + 6 H2O + ATP or energy
The first event is the ____(1)____ to form ____(2)____.
Transition reactions between glycolysis and the Krebs cycle
(1) decarboxylation (removal of a carboxyl (-COO-) group)
(2) carbon dioxide
The intermediate compound then donates ____(1)____ to ____(2)____ to reduce it to ____(3)____. Then a ____(4)____ is donated by ____(5)____ complete the formation of ____(6)____.
Transition reactions between glycolysis and the Krebs cycle
(1) donates two electrons
(2) NAD+
(3) NAD-
(4) hydrogen ion
(5) coenzyme A
(6) NADH
The ____ then attaches to the positive charge left on the ________ forming _________.
Transition reactions between glycolysis and the Krebs cycle
The coenzyme A ion (blue) then attaches to the positive charge left on the acetyl ion forming acetyl CoA.
____ is the stage of cellular respiration following glycolysis and
decarboxylation of pyruvate.
Krebs cycle
A cycle of reactions catalyzed by enzymes in which pyruvate derived from
nutrients and converted to Acetyl coenzyme A is completely oxidized and
broken down into CO2 and H2O to produce high-energy phosphate
compounds which are the source of cellular energy.
Krebs cycle
In Eukaryotes, the Krebs cycle occurs in the (1) whereas in prokaryotes, it occurs in the (2)
(1) matrix of the mitochondrion
(2) cytoplasm
The cycle begins with the reaction between (1) and the
(2) to form (3)
(1) acetyl-coA
(2) four carbon oxaloacetate
(3) six carbon citric acid
Through the next steps of the cycle, two of the six carbons of the
citric acid leave as (1) to ultimately yield the four
carbon product, (2), which is used again in the first step
of the next cycle
(1) Carbon Dioxide
(2) Oxaloacetate
During the eight reactions that take place, for every molecule of
acetyl-coA the cycle produces ____ NADH and ____ flavin
adenine dinucleotide (FAD/FADH2)
(How many?)
three, one
What happens during the 1st reaction?
Krebs Cycle
ENZYME: citrate synthase.
- oxaloacetate is joined with acetyl co-A then citric acid is formed
- once joined, a water molecule attacks the acetyl leading to the release of coenzyme A
What happens during the 2nd reaction?
Krebs Cycle
ENZYME: acontinase
- a water molecule is removed from the citric acid then put back on in another location
- –OH group is moved from the 3’ to the 4’ position on the molecule.
- yields isocitrate
What happens during the 3rd reaction?
Krebs Cycle
ENZYME: isocitrate dehydrogenase
- first generation of NADH from NAD
- oxidation of the –OH group at the 4’ position of the isocitrate to yield an intermediate
- carbon dioxide molecule removed is from that intermediate
- then yields alpha ketoglutarate
What happens during the 4th reaction?
Krebs Cycle
ENZYME: alpha-ketoglutarate dehydrogenase
- alpha-ketoglutarate loses a carbon dioxide and coenzyme A is added in its place.
- decarboxylation occurs with the help of NAD, which is converted to NADH
- yields succinyl-coA
The mechanism of this conversion is very similar to what occurs in the first few steps of pyruvate metabolism
What happens during the 5th reaction?
Krebs Cycle
ENZYME: succinyl-coA synthetase
- a free phosphate group attacks the succinyl-coA molecule releasing coA
- After the phosphate is attached to the molecule, it is transferred to the GDP to form GTP
- yields succinate
What happens during the 6th reaction?
Krebs Cycle
ENZYME: succinate dehydrogenase
- removal of two hydrogens from succinate
- a molecule of FAD is reduced to FADH2 as it takes the hydrogen from succinate
- yields fumarate
FAD oxidizes (1) while NAD oxidizes (2).
(1) carbon-carbon double and triple bonds
(2) mostly carbon-oxygen bonds
What happens during the 7th reaction?
Krebs Cycle
ENZYME: fumarase
- addition of a water molecule to the fumarate in the form of an –OH group
- yields L-malate
What happens during the 8th reaction?
Krebs Cycle
ENZYME: malate dehydrogenase
- regeneration of oxaloacetate by oxidizing L – malate with a molecule of NAD to produce NADH.
In the citric acid cycle , one (1) acetyl-coA molecule generates the following:
- The acetyl-coA, has been oxidized to two molecules of carbon dioxide
- Three (3) molecules of NAD were reduced to NADH x 2 = 6
- One (1) molecule of FAD was reduced to FADH2 x 2 = 2
- One (1) molecule of GTP. x 2 = 2
REMEMBER: There are two (2) pyruvates produced from each glucose, both the intermediate step and the cycle occur twice. So, x2 mo yung products
Computation for Total No. ATP (36-38)
GLYCOLYSIS:
2 NADH x 2/3 ATP = 4-6 ATP +
2 ATP
____________
6-8 ATP
DECARBOXYLATION OF PYRUVATE:
2 NADH x 3 ATP = 6 ATP
KREBS CYCLE
6 NADH x 3 ATP = 18 ATP +
2 FADH2 x 2 ATP = 4 ATP +
2 ATP
____________
24 ATP
TOTAL: 34-34 ATP
Computation for Total No. ATP (30-32)
GLYCOLYSIS:
2 NADH x 2.5/1.5 ATP = 3-5 ATP +
2 ATP
____________
5-7 ATP
DECARBOXYLATION OF PYRUVATE:
2 NADH x 2.5 ATP = 5 ATP
KREBS CYCLE
6 NADH x 2.5 ATP = 15 ATP +
2 FADH2 x 1.5 ATP = 3 ATP +
2 ATP
____________
20 ATP
TOTAL: 30-32 ATP
Each pair of electrons delivered by ________ is ultimately responsible for the formation of three (3) ATP molecules
ETC
NADH+ and H+
Those delivered by ________ responsible for the formation of two (2) ATP molecules
ETC
FADH2
Delivers two hydrogen atoms to a carrier at the top of the chain
ETC
NADH+ and H+
____ is the final electron acceptor, being reduced to water
ETC
Oxygen
The final carrier receives electrons from the previous carrier and passes them onto oxygen.
ETC
Cytochrome oxidase complex
What are the carriers in the chain
ETC
NADH dehydrogenase, Coenzyme Q, Cytochrome b-c1 complex, Cytochrome C, Cytochrome oxidase complex
