Question

The percentage of mitochondrial DNA in cell is
A) 10% of total cellular DNA
B) 1% of total cellular DNA
C) 2.5% of total cellular DNA
D) None of the above

Answer 1

Hint: DNA is the carrier of heredity. In the Eukaryotic cell the double stranded DNA is found in the nucleus. The DNA is also present in the chloroplast as well as mitochondria. This DNA is circular and synthesises proteins and enzymes for the functioning of the organelle.

Complete answer:
To answer this question, we must know about the DNA in the cell. DNA is the most important component of the cell which controls the functioning of the cell. The DNA is present in the nucleus. It is also present in the mitochondria and chloroplast.

Nuclear DNA- Most of the DNA present in the organism is the nuclear DNA. In eukaryotes, the DNA is double stranded and is present in thread-like structure called the chromatin. It codes most of the genome of the organism.

Mitochondrial DNA- Mitochondria is an important organelle in the eukaryotic cell which convert the chemical energy in the food to ATP which can be easily utilised by the organisms. Mitochondria has its own DNA which is called the mitochondrial DNA or mtDNA/mDNA. It constitutes around 1% of the cellular DNA.

Plastid DNA- Chloroplast DNA (cpDNA) is present in the organelle chloroplast. It is the genome of chloroplast which codes for the proteins needed for the functioning of chloroplast. It is also present in a very little quantity.

Thus the correct answer is option ‘B’.

Note: Both mitochondrial and chloroplast DNA are the extrachromosomal DNA. The structure of chloroplast and mitochondrial DNA is the same as that of the prokaryotic circular DNA. The mitochondrial DNA is inherited through the mother whereas the nuclear DNA is inherited from both the parents.