Question

How does temperature affect cellular respiration?

Answer 1

Hint: The set of chemical metabolic reactions that occur in living organisms to produce energy through the breakdown of food molecules or sugar molecules by the action of oxygen is called cellular respiration.

Complete answer:
The process through which the chemical energy of the organic food molecules is converted into chemical forms that can be used by the organisms to maintain and sustain their life functions is called cellular respiration. The reactants of this reaction are- oxygen and glucose. ATP (Adenosine Triphosphate) and waste products like- carbon dioxide and water are the products obtained. These reactions begin in the cytoplasm of the cell and then proceed to the double-membranous organelle- Mitochondria. It occurs in the autotrophic as well as heterotrophic organisms. It occurs in the sets of three metabolic pathways- Glycolysis, Krebs cycle, and the electron transport chain reaction. Glycolysis is an anaerobic process that converts 1 molecule of glucose into two molecules of Pyruvic acid. The other steps of cellular respiration can be anaerobic or aerobic, depending upon the availability of oxygen. Aerobic respiration occurs in the presence of oxygen and is common in most plants and animals. Anaerobic respiration occurs in the absence of oxygen and is common in most prokaryotes like bacteria and archaea. The net ATP production through cellular respiration is - 38 ATP (Glycolysis- 2, Kreb Cycle- 2, Electron transport chain- 34).

A change in temperature affects the- rate of cellular respiration significantly. An increase in temperature results in the absorption of heat, thus making the reaction endothermic. The absorbed heat increases the molecular energy of the reactants, which further increases the number of high-energy collisions amongst them. The reactant particles move more quickly and thus increase the rate of reaction. The cellular respiration in plants increases with an increase in temperature until the point- when a further increase in temperature will lead to tissue deterioration.
When the temperature is decreased, the molecular energy of the reactants is decreased. Thus, fewer collisions are observed. The molecules have lesser energy and thus they cannot pass the activation energy barrier of the reaction. The rate of reaction is decreased- due to fewer collisions. The cellular respiration in plants decreases with a decrease in temperature until the point- when a further decrease in temperature will lead to the freezing of the tissues and plants.
The rate of reaction is directly proportional to the change in temperature. Temperature is directly proportional to the Kinetic energy of the reaction/reactant molecules.

Note: Activation energy is the minimum amount of energy required by the molecules for their activation to undergo a chemical reaction. This energy helps in the formation and breaking of bonds. The source of activation energy is heat or thermal energy.