Question

What molecule accumulates during anaerobic respiration that causes muscle burning?

Answer 1

Muscle contraction occurs via metabolism of adenosine triphosphate (ATP) derived primarily from the simple sugar glucose.

Glucose NAD MADN 2 Pyruvate NAD 2 Lactate sore muscles

• ATP is required for muscle contraction. Four sources of this substance are available to muscle fibers: free ATP, phosphocreatine, glycolysis and cellular respiration.
• A small amount of free ATP is available in the muscle for immediate use.
• Phosphocreatine provides phosphates to ADP molecules, producing high-energy ATP molecules. It is present in low levels in the muscle.
• Glycolysis converts glucose to pyruvate, water and NADH, producing two molecules of ATP. Excess pyruvate is converted to lactic acid which causes muscle fatigue.
• Cellular respiration produces further molecules of ATP from pyruvate in the mitochondria. It is also required to resynthesize glycogen from lactic acid and restore stores of phosphocreatine and ATP in the muscle.
• During anaerobic respiration, your muscle cells use sugar to make ATP, but they don't use oxygen. This process produces lactate, which is quickly converted to lactic acid, which makes your Muscle burn. Lactic acid, as you may have experienced, makes it harder to exercise.