Question

The main function of mitochondria in a cell is
a) Secretion
b) Excretion
c) Osmoregulation
d) Respiration

Answer 1

Hint: Mitochondria is also known as the power-house of the cell as it takes part in a process that occurs in the presence of oxygen in eukaryotic cells and helps in the formation of energy currency of the cell.

Complete answer:
Mitochondria helps in the energy generation as it is required to keep up the structure and function of a cell. The process of breakdown of macromolecules by utilizing oxygen into micro molecules is respiration and occurs in mitochondria. The chemical energy Is stored in adenosine triphosphate (ATP) and used when required.

Each mitochondrion has two membranes. The outer membrane defines the organelle’s surface, while the inner membrane forms a series of sac-like cristae (singular: crista).
The solution enclosed within the inner membrane is called the mitochondrial matrix.
In eukaryotes, the chemical energy in carbohydrates and fats is used to produce ATP. in the inner membrane of the mitochondria most of the enzymes used in cellular respiration are present.
There are numerous copies of circular or linear chromosomes called mitochondrial DNA (mtDNA) in mitochondria.
The mitochondrial DNA contains only a tiny fraction of the genes responsible for the function of the organelle—the other genes reside in the nuclear DNA.

So, the correct answer is option d) Respiration.

Note:
Most of the proteins found in mitochondria are produced from ribosomes in the cytosol and imported into the organelle.
Mitochondria grow and divide independently of cellular division because they have their own DNA and 70s ribosomes.