Fermentation

Question 1

What goes into fermentation?

Answer 1

Pyruvate and NADH

Question 2

What is the major goal of lactic acid fermentation?

Answer 2

Convert NADH to NAD+

Question 3

What happens to pyruvate in lactic acid fermentation?

Answer 3

It is converted to lactic acid

Question 4

True or false: Ethanol fermentation is only performed by prokaryotes.

Answer 4

This statement is false. Although ethanol fermentation is much more common among prokaryotes than eukaryotes, certain eukaryotes can perform these reactions. The most notable example is yeast, which are single-celled eukaryotes that produce ethanol through ethanol fermentation. They are used to generate fermented food products, like alcoholic beverages.

Question 5

True or False: Lactic acid fermentation is a single step reaction

Answer 5

True. Lactic acid fermentation consists of a single reaction: the conversion of pyruvate to lactic acid by the enzyme lactate dehydrogenase. In the process, NADH is oxidized to NAD+.

Question 6

What enzyme is responsible for lactic acid fermentation?

Answer 6

Lactate dehydrogenase

Question 7

What are the two major enzymes in ethanol fermentation?

Answer 7

Pyruvate decarboxylase and alcohol dehydrogenase Ethanol fermentation is a bit more complicated. First, pyruvate decarboxylase converts pyruvate into acetaldehyde, releasing a molecule of carbon dioxide. Next, alcohol dehydrogenase converts acetaldehyde into ethanol, oxidizing NADH to NAD+.

Question 8

What enzyme is responsible for lactic acid fermentation?

Answer 8

Lacate dehydrogenase

Question 9

Describe lactic acid fermentation (what goes in, what comes out, who does it)

Answer 9

You start with Pyruvate and NADH. NADH gets oxidized to NAD+ and pyruvate gets reduced to lactate whcih is catalyzed by lactate dehydrogenase. This process does NOT create ATP.

Question 10

True or False: Fermentation creates ATP

Answer 10

False. It regenerates NAD+ to be resued in GLYCOLYSIS to make ATP

Question 11

Pyruvate Decarboxylase

Answer 11

Removes CO2 from pyruvate to create an acetaldehyde in the first step of ethanol fermentation

Question 12

Alcohol dehydrogenase

Answer 12

Second enzyme in ethanol fermentation that reduces acetaldehyde to ethanol to generate NAD+ from NADH

Question 13

What is the following reaction and what enzyme catalyzes it?

Answer 13

This is the first step of alcohol fermentation. The reactant on the left is pyruvate and it gets reduced to acetaldehyde releasing CO2. This is catalyzed by Pyruvate Decarboxylase

Question 14

What is the following reaction and what catalyzes it?

Answer 14

This is lactic acid fermentation catalyzed by lactate dehydrogenase.