According to the endosymbiotic theory, early eukaryotes acquired the mitochondri

Question

According to the endosymbiotic theory, early eukaryotes acquired the mitochondrion from a symbiotic bacterium. What happened to the bacterial genes?

All of the bacterial genes were transferred to the nuclear genome.

All of the bacterial genes still exist and comprise the mitochondrial genome.

All of the bacterial genes still exist and comprise the chloroplast genome.

Some bacterial genes were transferred to the nucleus, some were lost, and some comprise the mitochondrial genome.

All of the bacterial genes were transferred to the nuclear genome.

All of the bacterial genes still exist and comprise the mitochondrial genome.

All of the bacterial genes still exist and comprise the chloroplast genome.

Some bacterial genes were transferred to the nucleus, some were lost, and some comprise the mitochondrial genome.

Explanation / Answer

According to the endosymbiotic theory, the present day cell organelles, mitochondria and chloroplast have been evolved from prokaryotic bacteria when a large eukaryotic cell engulfed a tiny prokaryotic bacteria .

It is interesting that the eukaryotic cell did not digest the bacteria.

Endosymbionts are highly dependent on the host for their survival and growth.

As an endosymbiont evolves into organelle, most of the genes are transferred to the host cell genome.

Some of the genes already represented in the nucleus are lost. This is evident from the view that organelle genes are greatly reduced whereas nuclear genes are expanded and complex.

Most of the processes of mitochondroia and chloroplast are performed by the nucleus.

Mitochondria and chloroplast although have lost some of the genes, they are able to retain genes encdoding rRNAs, tRNAs, protein etc.,

Several hypothesis have benn proposed for the loss and retention of genes in the mitochondrai and chloroplast.

One such hypothesis is hydrophobicity hypothesis according to which, highly hydrophobic proteins are not easiy transported through the cytosol and thus these genes must be retained by the mitochondria and chloroplast.

Thus it is evidenced that some bacterial genes were transferred to the nucleus , some were lost and some comprise the mitochondrial genome.

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