Question

Energy releasing reaction in a cell occurs in:
A.Cell Wall
B. Ribosomes
C. Mitochondria
D. Plastids

Answer 1

The process by which energy is released by utilizing the nutrients is known as respiration. The process is controlled by a series of enzymatic reactions. The energy thus released is converted to ATP molecules, which are known as the energy currency of the cell.

Complete step by step answer: The energy-releasing process of respiration takes place in a cell organelle known as mitochondria. It is an organelle which is bound by two membranes, due to its ability to produce ATP molecules, the organelle is known as the powerhouse of the cell. It is found only in the cells of eukaryotic organisms. Out of the two membranes of the mitochondria, the inner membrane is the site for electron transport chain or aerobic respiration which is the process leading to the production of ATP. And this site consists of enzymes such as ATP Synthase.
Considering the other given options:
Cell Wall: It is the outermost layer present only in plant, fungal, and certain bacterial cells. It can be made up of a variety of materials. The plant cell walls are made up of cellulose, while fungal cell walls are made of chitin. The major function of this layer is in providing rigidity and support to the less rigid cell membrane. It also has a protective role.
Ribosomes: Ribosomes are the only cell organelles present in both eukaryotic and prokaryotic cells. These are seen either as dispersed in the cytoplasm or in contact with the endoplasmic reticulum in eukaryotic cells. The major function of these organelles is in intercellular protein synthesis through the process of translation.
Plastids: These are the organelles found exclusively in plant cells. There are three kinds of plastids known as chloroplasts, chromoplasts, and leucoplasts. Each of these having its unique functions. Chloroplasts help in the process of photosynthesis and it contains chlorophyll thus providing green color to the leaves, chromoplasts impart the other characteristic color to the plant parts. Leucoplasts have a role in the storage of lipids.
Thus from the above-given options, the most appropriate answer was found to be option C, that is the energy-releasing reaction in a cell occurs in the mitochondria.

Note: Another process of respiration occurring in the cell is known as glycolysis. It occurs in both prokaryotic and eukaryotic cells, and it is the only process of respiration occurring in prokaryotes since they are devoid of mitochondria. Glycolysis occurs in the cytoplasm.