What molecules decrease the rate of glycolysis and how? What molecules increase the rate of glycolysis and how?

Glycolysis is a metabolic pathway that is central to both aerobic and anaerobic respiration. It is tightly regulated by several molecules that can either increase or decrease its rate.

Molecules that decrease the rate of glycolysis:

1. ATP: High levels of ATP indicate that the cell has plenty of energy, so there's no need to break down more glucose. ATP inhibits phosphofructokinase, a key enzyme in glycolysis, slowing down the process.

2. Citrate: Citrate, a key component of the citric acid cycle, inhibits phosphofructokinase when its levels are high. This slows down glycolysis and prevents the accumulation of intermediates.

3. Alanine: This amino acid can inhibit pyruvate kinase, the enzyme that catalyzes the final step of glycolysis. This slows down the entire process.

Molecules that increase the rate of glycolysis:

1. AMP: AMP is a sign that the cell is running low on energy. It activates phosphofructokinase, speeding up glycolysis to produce more ATP.

2. Fructose 2,6-bisphosphate: This molecule is a powerful activator of phosphofructokinase, and thus speeds up glycolysis. Its levels are regulated by hormones like insulin.

3. ADP: Like AMP, ADP indicates that the cell needs more energy. It activates phosphofructokinase and pyruvate kinase, speeding up glycolysis.

In summary, the rate of glycolysis is controlled by the energy needs of the cell. When energy (in the form of ATP) is plentiful, glycolysis slows down. When energy is needed, glycolysis speeds up.