The first stage of anaerobic respiration is .

The first stage of anaerobic respiration is glycolysis.

Here are the steps:

1. Glycolysis takes place in the cytoplasm of the cell. It is the process of breaking down one molecule of glucose (a six-carbon molecule) into two molecules of pyruvate (a three-carbon molecule).

2. During this process, two molecules of ATP (adenosine triphosphate) are used up, but four molecules are produced, resulting in a net gain of two ATP molecules.

3. In addition, two molecules of NAD+ (nicotinamide adenine dinucleotide) are reduced to form two molecules of NADH.

4. The two molecules of pyruvate then proceed to the next stage of anaerobic respiration, which varies depending on the type of organism and the availability of oxygen. In humans, if oxygen is not available, the pyruvate is converted into lactate in a process called lactic acid fermentation. In yeast and some bacteria, the pyruvate is converted into ethanol and carbon dioxide in a process called alcoholic fermentation.

The first stage of anaerobic respiration is glycolysis.

Here are the steps:

1. Glycolysis takes place in the cytoplasm of the cell. It is the process of breaking down glucose, a six-carbon sugar, into two molecules of pyruvate, a three-carbon compound.

2. The glucose molecule is phosphorylated by two ATP molecules to form fructose 1,6-bisphosphate. This step requires energy.

3. Fructose 1,6-bisphosphate is then split into two three-carbon molecules.

4. Each of these molecules is converted into pyruvate, generating ATP and NADH in the process.

5. The net gain from glycolysis is two ATP molecules and two NADH molecules for each glucose molecule that is metabolized.

6. If oxygen is present, the pyruvate will continue on to the Krebs cycle for further energy extraction. If oxygen is not present, the pyruvate will undergo fermentation to regenerate NAD+ so that glycolysis can continue.