Question

The percentage of mitochondrial DNA in the cells 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

The correct option is D None of the above

In a eukaryotic cell, DNA is not only present in the nucleus but also in cell organelles like mitochondria and chloroplasts. The mitochondrial genome is built of 16,569 base pairs, whereas the nuclear genome is made of 3.3 billion DNA base pairs. In humans, mitochondrial DNA (mtDNA) forms closed circular molecules with each such molecule normally containing a full set of the mitochondrial genes. Each human mitochondrion contains, on average, 5 such mtDNA molecules. Each human cell contains approximately 100 mitochondria, hence approximately 500 mtDNA molecules per human cell are present. Hence, mitochondria contain less than 1 percent of cellular DNA. Since the amount of DNA is variable and not fixed. Thus, the correct answer is option D.