Question

What is cellular respiration in a plant cell?

Answer 1

Hint: Two types of cellular respiration are seen in plants– a) aerobic respiration and b) anaerobic respiration. In most cases, aerobic respiration is performed but in some exceptional cases (when roots of plants are submerged in water) anaerobic respiration occurs. The main difference between aerobic and anaerobic respiration lies in the fact of the presence of free molecular oxygen species inside the cell.

Complete answer:
Cellular respiration can be defined as a biochemical and enzymatically controlled catabolic process by which a respiratory substrate (glucose) present inside the cell is oxidized in the presence or absence of free oxygen. In this process, the stored potential energy from the food is transferred to kinetic energy for the performance of metabolic activities. The process of respiration occurs in two steps. The first step includes glycolysis and the second step includes Krebs’ cycle and Electron Transport System.
Two types of reaction are seen in the case of cellular respiration :
Oxidation –
By the addition of oxygen(a process by which food is oxidized).
Dehydrogenation (in the case of aerobic respiration the glucose is oxidized in a stepwise manner by removal of hydrogen. This hydrogen is used in the reduction of hydrogen carrier NAD and finally is oxidized to water).
By removal of electrons-
Decarboxylation - Removal of carbon from compounds to produce carbon dioxide.
The terminal electron acceptor of aerobic respiration is oxygen. The principle reaction is involved in the production of $6$molecules of carbon dioxide and $6$ molecules of water and the release of $686$ kcal of energy.
In the case of anaerobic respiration, the terminal electron acceptor is an inorganic acid. The product evolved here is $2$molecules of ethyl alcohol and $2$ molecules of carbon dioxide and releases $50$ kcal of energy.

Note:
The process of respiration occurs in the cytoplasm and mitochondria of the cell. The glycolysis process occurs within the cytoplasm and the Krebs cycle and ETS occurs in mitochondria. It is to be kept in mind that though plants require oxygen, they don't possess any specialized organ for the exchange of gases, and also the transport of gases from one plant to another is very limited. Oxygen is taken up by stomata and the lenticels.