Question

11) (a) During fermentation, cells generate ATP via...circle all that apply Electron Transport Chain or Citric Acid Cycle or Glycolysis (b) If a cell ran out of NAD", then would that cell be able to continue performing glycolysis? If you say "no", then identify the specific step of glycolysis (draw it) that requires NAD. (c) During aerobic respiration, NAD* is regenerated when NADH donates its H atom to the electron transport chain. Explain how NAD is regenerated during fermentation. (d) During the process of fermentation, pyruvic acid is... oxidized or reduced (e) After pyruvic acid undergoes the chemical modification you indicated in part d, it becomes converted to what? There are two possible answers to this question. (f) Which of the following processes requires the presence of oxygen? Aerobic respiration or Fermentation (g) Which of the following processes generates more ATP per glucose molecule? Aerobic respiration or Fermentation (h) Explain your answer to partg

Answer 1

According to guidelines I can only give the answer to the first 4 parts. Please post remaining in as another question.

A. Fermentation is the process of producing ATP in the absence of oxygen, through glycolysis alone.

B. Glycolysis requires two molecules of NAD+ per glucose molecule, producing two NADH as well as two hydrogen ions and two molecules of water.

During this step, NAD+ is used. Two half-reactions occur simultaneously: 1) Glyceraldehyde-3-phosphate (one of the three-carbon sugars formed in the initial phase) is oxidized, and 2) \text{NAD}^{+}NAD+start text, N, A, D, end text, start superscript, plus, end superscript is reduced to \text{NADH}NADHstart text, N, A, D, H, end text and \text{H}^+H+start text, H, end text, start superscript, plus, end superscript. The overall reaction is exergonic, releasing energy that is then used to phosphorylate the molecule, forming 1,3-bisphosphoglycerate.

I have attached an image of this step.

2x c=0 H-C-OHO Glyceraldehyde H-C-o-Po 3-phosphate HO Glyceraldehyde- NAD+P; 3-phosphate dehydrogenase NADH + H+ P ADPO Cao sphoglycerate H-C-OHO Se H-C-O-Pro но- 1,3-Bisphosphoglycerate te

C. Going from pyruvate to ethanol is a two-step process. In the first step, a carboxyl group is removed from pyruvate and released in as carbon dioxide, producing a two-carbon molecule called acetaldehyde. In the second step, \text{NADH}NADHstart text, N, A, D, H, end text passes its electrons to acetaldehyde, regenerating \text{NAD}^+NAD+start text, N, A, D, end text, start superscript, plus, end superscript and forming ethanol.

I have attached image.

Glucose Glycolysis 2 NAD+ 6 72 NADHI 2 ADP 2 ATP}* (net) 2 Pyruvate NAD+ Regeneration) 1 2002 2 Acetaldehyde - 2 NADH 1 2 NAD+ 2 Ethanol

D. Under these conditions, pyruvate undergoes a process termed fermentation, whereby pyruvate is reduced and NADH is oxidized to regenerate NAD+..