Question

What is the term for conversion of acetyl CoA into energy in the form of ATP in the presence of oxygen?

a. oxidative phosphorylation

b. citric acid cycle

c. proton gradient

d. cellular respiration

e. electron-transport chain

Answer 1

Cellular respiration in eukaryotes is used to break down sugars(glucose) in the presence of oxygen to produce ATP energy which is required for many cellular processes. It consists of several steps and they are:

1. Glycolysis

2. Pyruvate Oxidation

3. Citric Acid cycle/ Kerbs cycle

4. Electron transport chain/ Oxidative phosphorylation

In Glycolysis, the glucose of converted into 2 pyruvate molecules, ATP and NADH. In pyruvate oxidation, the pyruvate molecules are converted into acetyl CoA, NADH, and CO2. In the citric acid cycle or the Krebs cycle, the acetyl CoA reacts with four molecules of carbon in the presence of oxygen to form ATP, NADH, FADH2, and CO2. Finally, in the electron transport chain or oxidative phosphorylation, the NADH and FADH2 send electrons down the electron transport chain where the protons are pumped out to form a proton gradient. The protons are converted to ATP thanks to ATP synthase and oxygen at the end of the electron transport chain accepts the electron and takes up the protons to form water.

ANSWERS:

a. oxidative phosphorylation: this step is synonymous with the electron transport chain, where NADH and FADH2 transfer electrons into the electron transport chain. This step produces the highest number of ATP. Therefore, this is not the answer.

b. CITRIC ACID CYCLE: This step converts acetyl CoA in the presence of oxygen to form ATP. Therefore, citric acid cycle is the answer.

c. proton gradient: The proton gradient is the protons pumped by the electron transport chain while electrons are transported down the chain.Therefore, this is not the answer.

d. Cellular respiration: Cellular respiration is the chemical process by which a cell can produce the necessary energy by breaking down glucose. It takes place in the mitochondria. Therefore, this is not the answer.

e. electron-transport chain: The electron transport chain is a series of complexes that transport electrons from NADH and FADH2 to oxygen which is the final electron acceptors. Therefore, this is not the answer.