17 Which of the following statements is INCORRECT regarding oxidative phosphoryl
ID: 59269 • Letter: 1
Question
17 Which of the following statements is INCORRECT regarding oxidative phosphorylation and substrate level phosphorylation?
A) The process of oxidative phosphorylation refers to the electrochemical gradient used for the synthesis of the high energy bond of ATP
b) Oxidative phosphorylation is an example of an aerobic pathway
c) Substrate level phosphorylation is particularly important for converting fuel energy to ATP in red blood cells
d) Oxidative phosphorylation stops if oxygen is removed
e) The generation of ATP during the conversion of glucose to lactate is an example of oxidative phosphorylation
18- Which of these statements are TRUE?
a) Because NADH enters the electron transport chain at complex I, energy is released from the oxidation of NADH to synthesize three ATP.
b) Since FADH enters the chain at a lower energy level at complex II, it only provides energy to drive the synthesis to produce two ATP.
c) The NADH produced in glycolysis cannot pass through the mitochondrial membrane to the electron transport chain.
d) The hydrogen ions and electrons from NADH in the cytoplasm are transferred to compounds that can enter the mitochondria.
e) In the glycerol shuttle system, dihydroxyacetone phosphate, a compound in glycolysis that can enter the mitochondria, is reduced to glycerol-3- phosphate and NAD is regenerated
f) After glycerol-3-phosphate crosses the mitochondnal membrane, the hydrogen ions and electrons are transferred to FAD.
g) FADH is produced along with glycerol-3-phosphate, which returns to the cytoplasm. h) The overall reaction for the glycerol-3-phosphate shuttle is
NADH + H+ + FAD- NAD+ + FADH2
(cytoplasm) (mitochrondia)
i) all of the above
19- Which of these statements are TRUE about the transport of reducing equivalents?
A In skeletal muscle and brain cells, the glycerol phosphate shuttle produces FADH2 and thus the total combustion of glucose results in only 36 ATP
B In liver, kidney and heart cells, the malate aspartate shuttle produces NADH + H+ and thus the total combustion of glucose results in 38 ATP.
C If NADH + H+ appears inside the mitochrondrion, during the transport of reducing equivalents then its energy is converted into 3 ATP via electron transport and oxidative phosphorylation, but if FADH2 appears, then only 2 ATP are made, because NADH + H+ enters the electron transport chain at a higher level than FADH2.
D. The net result of the glycerol phosphate shuttle is that there is a continual conversion of the glycolytic intermediate, DHAP and glycerol-3-phosphate with the concommitant transfer of the electrons from reduced cytosolic NADH to mitochondrial oxidized FAD+.
E Within the mitochondria the electrons of NADH produced in glycolysis can be coupled to ATP production during the process of oxidative phosphorylation.
F. all of the above
20. Free Fatty acid production in DKA is favored by:
a. increased insulin and increased glucagons
b. increased insulin and decreased glucagons
c. decreased insulin and decreased glucagon
d. decreased insulin and increased glucagon
e. none of the answers shown are true.
Explanation / Answer
17 ans) The incorrect statement is - (e) The generation of ATP during the conversion of glucose to lactate is an example of oxidative phosphorylation
“Oxidative phosphorylation” is an aerobic process that involves a series of reactions, which include the transfer of electrons from the NADH or FADH2to oxygen. This process involves the transfer of electrons (oxidation) by a series of electron carriers (electron transport system (ETS)) and attachment of phosphate group (phosphorylation). Oxidative phosphorylation electro chemical gradient is used for the generation of ATP. If oxygen is not present ETS doesn't work. So in the absence of oxygen oxydative phosphorylation will stop generating ATP.
Substrate level phosphorylation mainly occurs in the cytosol. It is important to generate ATP in RBC due to the absence of mitochondria in the RBC.
The generation of ATP during the conversion of glucose to lactate is an example of "anaerobic glycolysis"
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