Science (086) — AI-generated practice question

Read the following case and answer the questions that follow. Ravi is a healthy 15-year-old boy. One day during a sprint race, he feels severe cramps in his leg muscles. After the race, his doctor explains that during intense exercise, his muscle cells did not receive enough oxygen, so they switched to a different pathway for energy generation. The doctor also mentions that the oxygen he breathes is carried to his muscles by a pigment in his blood, and that the carbon dioxide produced is transported back to his lungs. (i) Name the 'different pathway' the muscle cells switched to, and name the end product responsible for the cramps. (ii) Name the pigment that carries oxygen in the blood and the cells in which it is found. (iii) How is carbon dioxide transported from the muscles back to the lungs according to the chapter? (iv) Once oxygen is restored to the muscle cells, in which part of the cell does aerobic respiration (the breakdown of pyruvate) occur?