Biology 9700 · AS & A Level · Respiration

Respiration — practice question

All living organisms carry out respiration to release energy from energy-rich compounds such as glucose.
(a(i))[2]

Anabolic reactions require energy to occur. State two examples of anabolic reactions that take place in living organisms.

(a(ii))[3]

Describe and explain how ATP is used in glycolysis.

(b)

In the early 20th century, some factory workers were exposed to chemical X and suffered severe side-effects. Exposure to chemical X can cause: • reduced ATP production • greater lipid metabolism, leading to weight loss • more pyruvate and lactate being produced • release of excess heat energy, which raises body temperature and may be fatal. Chemical X makes the inner mitochondrial membrane more permeable to protons (hydrogen ions), so some protons leak into the matrix.

(b(i))[3]

Explain why exposure to chemical X leads to: • decreased ATP production • increased lipid metabolism.

(b(ii))[2]

Suggest and explain why chemical X leads to greater production of pyruvate and lactate.

(b(iii))[1]

Suggest why so much heat energy is given out.

(i)[3]

Explain why exposure to chemical X leads to: • decreased ATP production • increased lipid metabolism.

(ii)[2]

Suggest and explain why chemical X results in more pyruvate and lactate being produced.

(iii)[1]

Suggest why heat energy is released in excess.

Worked solution & mark scheme

This 17-mark question has a full step-by-step worked solution and mark scheme. One marking point: idea of making larger molecules from smaller units

  • Full mark scheme, point by point
  • Step-by-step worked solution
  • Write your answer & get it marked instantly by AI