What happens under anaerobic conditions in beer yeast?Group of answer choicesLactate is formed by the pyruvate dehydrogenase complex.Ethanol is formed by the alpha-ketoglutarate dehydrogenase complex of the TCA cycle.NAD+ is regenerated by lactate dehydrogenase to allow glycolysis to proceed.NADH is converted back into NAD+ by the enzyme alcohol dehydrogenase.Acetaldehyde is oxidized to produce ethanol.

Under anaerobic conditions in beer yeast, the following steps occur:

1. Glycolysis: This is the process where glucose is broken down into pyruvate, producing ATP (energy) and NADH in the process.

2. Pyruvate Decarboxylation: The pyruvate produced in glycolysis is then converted into acetaldehyde. This process also releases carbon dioxide (CO2), which is what causes the bubbles in beer.

3. Alcohol Fermentation: The acetaldehyde is then converted into ethanol by the enzyme alcohol dehydrogenase. This step also converts NADH back into NAD+, which is necessary for glycolysis to continue.

So, the correct answers from your options are:

• NADH is converted back into NAD+ by the enzyme alcohol dehydrogenase.
• Acetaldehyde is oxidized to produce ethanol.

The other options are not correct because lactate and the TCA cycle are not involved in the anaerobic respiration of beer yeast.