7.6 anaerobic respiration- fermentation

Question 1

Pyruvate has many possible fates in the cell. In the absence of oxygen, it can be broken down by

Answer 1

fermentation

Question 2

how is fermentation accomplished?

Answer 2

through a wide variety of metabolic pathways that extract energy from fuel molecules like glucose.

Question 3

Why is fermentation important?

Answer 3

for anaerobic organisms that live without oxygen or when oxygen can’t be delivered fast enough in aerobic organisms.

Question 4

What are the 2 major fermentation pathways?

Answer 4

lactic acid fermentation

ethanol fermentation

Question 5

when does lactic acid fermentation occur? and what happens

Answer 5

in animals and bacteria. electrons from NADH are are transferred to pyruvate to produce lactic acid and NAD+
Glucose+ 2ADP +2Pi -> 2 lactic acid + 2ATP + 2H20

Question 6

when does ethonol fermentation occur? and what happens

Answer 6

in plants and fungi. pyruvate release carbon dioxide to form acetaldehyde, and electrons from NADH are transferred to acetaldehyde to produce ethanol and NAD+
Glucose+ 2ADP + 2Pi -> 2ethanol + 2CO2 + 2ATP + 2H20

Question 7

How did early cells meet their energy requirements?

Answer 7

• Early cells evolved mechanisms to. pump protons out of the cell, powered by ATP and electron transport.
• Eventually electron transport powered pumps became efficient enough to run the ATP-driven pump in reverse