Due to excessive workout, an athlete was suffering from fatigue. He was advised to take rest for some time and rejoin a. Why did he feel tired after the exercise? b. Why was he asked to take rest and then join the practice again?
A) The glucose undergoes metabolism in the presence of oxygen to form ATP(adenosine triphosphate) which is essential for muscle contraction. But during vigorous exercise, the body cannot meet the oxygen demand and the glucose undergoes metabolism in the absence of oxygen which results in the formation and accumulation of lactic acid. Feeling of fatigue after running fast for some time is due to the accumulation of lactic acid in muscles.
B)Taking rest will allow the body to replenish energy, stores and repair damaged tissues. Without sufficient time to repair and replenish, the body will continue to break down from intensive exercise.
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Breaking down of glucose can occur by different pathways;
In presence of oxygen: -
Breaking down of glucose into pyruvate (in cytoplasm) takes place in Mitochondria of a cell and End products are CO₂ , H₂O and energy.
Glycolysis is the breakdown of glucose in first step. Which common to both types of respiration. It occurs in cytoplasm. In glycolysis process, one molecule of glucose (6-carbon molecule) is broken down into two molecules of pyruvic acid or pyruvate (3-carbon molecule) with four molecules of ATP.
In insufficient presence of oxygen: -
In muscle cells, the cells undergoes anaerobic respiration due to insufficient presence of oxygen & forming Lactic acid and lot amount of energy.
In absence of Oxygen: -
In absence of Oxygen, glucose breakdown into pyruvate in cytoplasm only & final product are Ethanol, and small amount of energy
The energy obtained during cellular respiration is immediately used to synthesise a molecule called ATP which is used to fuel all other activities in the cell.