Under anaerobic conditions (a lack of oxygen), the conversion of pyruvate to acetyl coa stops. which of these statements is the correct

Under anaerobic conditions (a lack of oxygen), the conversion of pyruvate to acetyl coa stops. which of these statements is the correct explanation for this observation? which of these statements is the correct explanation for this observation? a) oxygen is required to convert glucose to pyruvate in glycolysis. without oxygen, no pyruvate can be made. b)atp is needed to convert pyruvate to acetyl coa. without oxygen, no atp can be made in oxidative phosphorylation. c)oxygen is an input to acetyl coa formation. d) in the absence of oxygen, electron transport stops. nadh is no longer converted to nad+, which is needed for the first three stages of cellular respiration.


The answer is c)oxygen is an input to acetyl CoA formation.


After pyruvate is produced during glycolysis, its fate depends on oxygen availability. If there is enough oxygen available then pyruvate will enter the citric acid cycle, also called Krebs cycle. Pyruvate will then be oxidized by the pyruvate dehydrogenase complex into acetyl-coA and CO2. However, if there is not enough oxygen available, then pyruvate will undergo a reduction reaction by the lactate dehydrogenase enzyme and produced lactate along NAD+ production from NADH.

a. No, because Acetyl CoA goes into the TCA cycle, which will not occur in cells without oxygen.


Fatty acids in the body gets converted to acetyl-CoA by the process of β-oxidation. After the conversion of fatty acids to acetyl-CoA , acetyl-CoA undergoes the TCA cycle which produces NADH and FADH₂ which further undergoes electron transport chain where oxygen gas acts as the final receptor for these molecules and high energy molecules known as ATP are released in the process.

Thus, in the absence of oxygen, TCA will not occur and thus no energy is provided to the body.

anaerobic respiration is the respiration that takes place due to absence of oxygen

Organisms like yeast can survive in absence of oxygen

Cellular respiration that proceeds in the absence of oxygen is anaerobic respiration. 


A is correct because energy from electrons from oxygen are used to pump the H+ (as well as electrons from NADH) It's not D because glycolysis happens both in absence and presence of oxygen and never uses O2 so glycolysis is the same in both processes, its what happens after glycolysis that is dependent on the availability of oxygen (oxidative phosphorylation or fermentation)

Glycolysis is not an oxygen dependent process and the rate of glycolysis is not affected by the amount of oxygen present. The amount of oxygen present affects the rate of oxidative phosphorylation in the mitochondria. Hence with more oxygen present, there is increased oxidative phosphorylation in the presence of high amounts of final electron acceptor O2 which pumps more protons across the membrane and results in a steeper proton gradient across the mitochondrial membrane thus increasing the rate of ATP production. Thus the answer is A as the rate of proton pumping is increased with higher rate of oxidative phosphorylation due to the abundance of final electron acceptor O2.

Letter a. Yes, yeasts can exist in an oxygen-poor environment.


Mitochondria are an organelle that we can find in the majority of eukaryotic cells. Mitochondria help in produces the energetical molecule of ATP. We start with one molecule of glucose that passes through a process called glycolysis to convert glucose into pyruvate. This pyruvate molecule can follow two pathways: when oxygen is available the pyruvate enter into the Krebs cycle and proceeds to the respiratory chain in the mitochondria, when oxygen is not present, pyruvate pass into another pathway, one is the alcoholic fermentation producing ethanol and dioxide of carbon.

As yeast are a eukaryotic organism, they have mitochondria and can grow in the presence of oxygen. When oxygen is absent yeast can grow using the fermentation pathway producing alcohol.

No, glycolysis can not be continued without fermentation in the absence of oxygen.


In the absence of oxygen, cells perform fermentation to oxidize NADH into NAD+. NAD+ is required during the conversion of glyceraldehyde 3 phosphate into 1,3 bisphosphoglycerate. Fermentation reduces pyruvate and oxidizes NADH so that the NAD+ supply is continued to ensure continuity of glycolysis.

If fermentation does not occur under anaerobic conditions, cells will accumulate pyruvate and NADH. Glycolysis could not be continued in the absence of NAD+.

The cells exhibit all these stages in the presence of oxygen only.

C. The only way to start respiration is if oxygen is present; Otherwise, it would go through fermentation

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