During cellular respiration, _____ is reduced to eventually form _____.

Question

BlackTom AI · Accepted Answer

Oxygen acts as the final electron acceptor in aerobic respiration and is reduced to form water.

1) Relevant knowledge points and concepts
- Oxidation-reduction: oxidation = loss of electrons, reduction = gain of electrons.  
- In cellular respiration, organic fuels (e.g., glucose) are oxidized; electron carriers (NAD+ and FAD) are reduced to NADH and FADH2, which then donate electrons to the electron transport chain (ETC).  
- The ETC transfers electrons to the terminal electron acceptor, O2, which is reduced to H2O. This reduction drives proton pumping and ATP synthesis.

2) Step-by-step reasoning
- Glucose is oxidized through glycolysis, pyruvate oxidation, and the citric acid cycle; electrons are carried by NADH and FADH2 to the inner mitochondrial membrane.  
- At the end of the ETC, molecular oxygen accepts electrons (and protons) to form water. Thus oxygen is the species that is reduced.

3) Calculations and intermediate steps (chemical equations)
- Overall combustion-like equation: C6H12O6 + 6 O2 → 6 CO2 + 6 H2O. Here glucose is oxidized to CO2; O2 is reduced to H2O.  
- Half-reaction for oxygen reduction: O2 + 4 e– + 4 H+ → 2 H2O. This shows O2 gaining electrons and protons to produce water.

4) Why the correct answer is correct
- The ETC explicitly transfers electrons to O2; the reduction product is water. Therefore oxygen is reduced to eventually form water during aerobic cellular respiration.

5) Why the other options are incorrect
- (a) sugar → carbon dioxide: sugar is oxidized (loses electrons) to CO2, not reduced.  
- (c) oxygen → sugar: oxygen is not reduced to form sugar; sugar is the electron donor in respiration, not the product of oxygen reduction.  
- (d) water → carbon dioxide: water is a reduction product, not the species that is reduced to CO2.

6) Conclusion
- This confirms the correct choice is b. oxygen; water.

During cellular respiration, _ is reduced to eventually form _.单项选择题

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During cellular respiration, _____ is reduced to eventually form _____.单项选择题

类似问题

What is the term for the process by which cells convert glucose into energy?

Question at position 14 Indirect calorimetry is based upon the concept that Oxygen is used in ATP production and ___ is a by-product of ATP production.NADHFADH2WaterCarbon dioxide

Question at position 13 For an unknown macronutrient, approximately 14 molecules of oxygen are required for oxidation and 10 molecules of carbon dioxide are produced. The RQ of this molecule is:0.930.830.711.00

Which of the following stages of cellular respiration directly produces the LEAST reduced electron carriers?

Which of the following stages of cellular respiration directly produces the LEAST reduced electron carriers?

The primary function of the mitochondrion is the production of ATP. To carry out this function, the mitochondrion must have all of the following except

Which of the following cellular processes would be most directly interfered with (ignoring downstream processes) by a toxin that binds to pyruvate and inactivates it?

How many ATP molecules are generated from the complete oxidation (aerobic utilisation) of one glucose molecule?

更多留学生实用工具

希望你的学习变得更简单

During cellular respiration, _ is reduced to eventually form _.单项选择题