Answer :
Answer: B) Lactic acid accumulates in muscles cells during anaerobic respiration when oxygen levels are low, leading to temporary muscle fatigue and soreness.
Explanation: Lactic acid is a product of lactic acid fermentation, a form of cellular respiration that occurs when there is a lack of oxygen in our bodies. (such as during intense exercise or instances when the respiratory system is not functioning optimally) Thus, lactic acid fermentation is a form of anaerobic respiration. (thus making answer choice A and D incorrect)
Lactic acid fermentation occurs after glycolysis. During this form of fermentation, pyruvate is converted into lactate with the addition of two hydrogen atoms from NADH, converting NADH into NAD+. The purpose of this process is to convert NADH into NAD+ so that it can be reused in glycolysis to produce ATP. However, as lactic acid builds up in cells, it causes fatigue and soreness in muscle cells. Afterwards, lactic acid is converted back into pyruvate in the liver to be reused in either aerobic or anaerobic respiration. (depending on the oxygen conditions)
Lactic acid is not involved in the synthesis of fatty acids, thus making choice C incorrect. Thus, the best description of lactic acid is that it's a product of anaerobic respiration that may cause soreness in muscles upon accumulation.
