Cells are able to keep the concentration of ions inside the cell different from that in the extracellular environment. It is estimated that animals may use $50\%$ of ATP made by respiration to maintain higher concentrations of some ions inside cells. Name the mechanism that can maintain a higher concentration of ions inside a cell.
Only part of the energy released when glucose is respired is converted into ATP. The energy yield from aerobic respiration of glucose is $2870\ \text{kJ mol}^{-1}$. When ATP is hydrolysed to ADP, it releases $30.5\ \text{kJ mol}^{-1}$ of energy. It is estimated that $31$ moles of ATP are produced per mole of glucose respired. Calculate the percentage efficiency of glucose respiration. Show your working.
The energy that is not turned into ATP during respiration is given out as heat energy. State one homeostatic use of this heat energy in mammals.
State the term used for the reaction that leads to ATP being produced during the Krebs cycle.
When a person exercises, power is produced. Power is measured in joules per second $(\text{J s}^{-1})$. An experiment was carried out to find out whether increasing the intensity of exercise in a healthy human male led to a change in the value of the respiratory quotient (RQ). The results are shown in Fig. 2.1. Referring to Fig. 2.1, suggest what can be deduced from: the RQ at rest; the RQ when the power produced is $110\ \text{J s}^{-1}$; the RQ when the power produced is $200\ \text{J s}^{-1}$.
Explain why a person keeps breathing deeply and at a higher rate for some time after stopping exercise.