7.5: Fermentation and anaerobic respiration enable cells to produce ATP without the use of oxygen

Question 1

What happens if there is no oxygen or not much.

Answer 1

We resort to anaerobic or fermentation

Question 2

Anaerobic respiration

Answer 2

uses ETC but with a different final electron acceptor

Question 3

Fermentation

Answer 3

Starts with Glycolysis, uses SLP and not the ETC, replenishes NAD+

Question 4

What are 2 common types of Fermentation

Answer 4

Lactic Acid Fermentation and Alcoholic Fermentation

Question 5

Alcoholic Fermentation steps

Answer 5

Pyruvate is converted to ethanol in two steps. The First step releases CO2 from pyruvate and the Second step reduces acetaldehyde to ethanol

Question 6

Lactic acid fermentation

Answer 6

pyruvate is reduced by NADH, forming lactate as an end product, with no release of CO2. Used by human muscles when there is a lack of O2

Question 7

2 Similarities between Fermentation, Aerobic, and Anaerobic

Answer 7

• All use glycolysis(net ATP = 2) to oxidize glucose and harvest chemical energy of food
• In all three, NAD+ is the oxidizing agent that accepts electrons during glycolysis

Question 8

2 differences between Fermentation, Aerobic, and Anaerobic

Answer 8

• The processes have different final electron acceptors: an organic molecule in fermentation and O2 in cellular respiration
• Cellular respiration produces 32 ATP per glucose molecule; fermentation produces 2 ATP per glucose molecule

Question 9

Obligate anaerobes

Answer 9

carry out only fermentation or anaerobic respiration and cannot survive in the presence of O2

Question 10

Facultative anaerobes, how does pyruvate act here

Answer 10

are yeast and other bacteria, meaning they can survive using either fermentation or cellular respiration, pyruvate is a fork in the metabolic road that leads to 2 alternative catabolic routes

Question 11

Why was fermentation said to be used

Answer 11

Ancient prokaryotes used fermentation back when there was little to no O2 in the earth’s atmosphere

Question 12

Quick summary of cell resp.

Answer 12

C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy(ATP + heat)

Glycolysis: happens outside of mitochondria, reduces and oxidizes glucose into pyruvate

Krebs cycle: happens inside: pyruvate becomes Acetyl CoA, though oxidation, oxaloacetate is created, and the Krebs cycle starts again

ETC: at the IMS, electromagnetic gradient of protons is harnessed as they fall, they fall due to reduction.

Chemiosmosis: proton motive force is harnessed and over 26 ATP are formed.