Question

dna mitochondria

Answer 1

Mitochondrial DNA (mt DNA) are double stranded circular molecule that are only 16bp in length, and contains 16,600 bp.
They are haploid in nature and codes for 37 genes.
13 genes in it provide instructions for making enzymes involved in oxidative phosphorylation. (a process that uses oxygen and simple sugars to create ATP)
It contains 22tRNA and 2rRNA coding genes, contains only exons ,no introns.
There is presence of one D loop , that is a DNA triple helix where most of DNA replication and transcription are controlled.,
Mitochondria DNA can not distinguish between individuals of same maternal ineage..
Maternal inheritance of mitochondrial DNA:
It refers to the transmission of genes only through the female . , During fertilisation sperm only contributes its nuclear DNA .
Mitochondria of Sperm is locatedat the mitochondrial sheath which is destroyed upon fertilisation.
and so only DNA of mitochondria from mother is transferred.
The mitochondrial DNA has a very high mutation rate , 10 to 17 fold higher than that observed in nucear DNA. It is due to
a) insufficient DNA repair system
b) spontaneous error arising in DNA
c) Lack of DNa proteins ike histones.
Diseases associated with mt DNA are :
a) Leigh syndrome
b) Cytochrome c oxidase deficiency
c)Cycic vomitting syndrome etc.