Does anyone know why the human has both mitochondrial dna and nuclear dna?

Question

I was shocked to hear that the human possesses both mitochondrial dna, which is ancient and the function unknown and the beter known nuclear dna which controls all known functions and characteristics of the human species. Could anyone please tell me more about the function of the mitochondrial dna and the role of the rna. Thank-you!

Answer 1

Many scientists believe that mitochondria were actually ancient prokaryotes that were taken up by another, larger prokaryote--this may have led to the evolution of eukaryotes. All cells have DNA so it shouldn't be surprising that mitochondria also have some DNA still if this theory is true. Biologists do think that some of the mitochondrial DNA still functions, but many of its functions have been lost due to the lack of selective pressure (if it is not needed because of redundencies in the nuclear DNA from the larger organism then it will change and likely become obsolete over time). Hope that helped...and fyi chloroplasts also have their own DNA (probably for the same reason).

Answer 2

mitochondria, is thought to be a prokaryotic organism,which was engulfed by a eukaryotic organism during evolution, and was not lost during it.It actually established a symbiotic relationship with the host, during this course.A few genes from this went to the nucleus, and thus it came under the control of nuclear DNA and bcame an organelle.

Though the mitochondria has the DNA, which codes for a few proteins, important in respiration and also its own replication, it is not independent.Many of the proteins req are still made by the nucleus and transported there.This theory of mitochondrial origin is called endosymbiotic theory.
precisely speaking, mitochondrial DNA codes for certain cytochromes, ATPases,rRNA and tRNA.

Coming to the second part, RNAs are nucleic acids, and basically, three types are found in the cell abundantly-mRNA, rRNA and tRNA.mRNA has the information for protein synthesis, rRNA helps in protein synthesis, and are present in the ribosomes, while tRNA also help in protein synthesis.

sometimes, RNA are also found as genetic material, as is seen in some viruses.

hope this helps....

Answer 3

Mitochondria is thought to be evolved from prokaryotes; it is belived that very long time ago, some kind of prokaryotes swallowed a smaller one, and formed together a symbiotic relationship, later on, the swallowed prokaryote evolved to the mitochondrion..

Scientist have mentioned some evidences about the truthness of this endosymbiosis theory:
(1) both the mitochondrion and the bacteria cell lack the nucleus, and have circular DNA.
(2) ribosomes of mitochondrion are similar to those of prokaryotes ( smaller than those of eukaryotes).
(3) both mitochondrion and prokaryotes multiply in the same way.

The DNA of the mitochondrion comes from the mother only, in fertilization, the sperms DNA is left outside!!

Mitochondrial DNA codes for some important proteins necessary for the syestems of the body,

a defect in the mitochondrial DNA can cause very serious diseases,

mitochondrial DNA is used nowadays for forensic purposes.

Plant cells also for your information has Chromosomal DNA, mitochondrial DNA, and chloroplast DNA..

Hope this help
thanks

Answer 4

DNA is transcribed into RNA which is translated into proteins. Nuclear DNA codes for most of the proteins needed. But the mitochondria needs some proteins that are not coded in nuclear DNA, they are coded by the mitochondrial DNA. This DNA is transcribed and translated inside the mitochondria and the proteins remain there for mitochondrial use.

Answer 5

The current theory is that a long, long time ago when life was evolving, mitochondria teamed up with other monocellular life to form a symbiotic relationship. Without mitochondria, eukaryotic organisms relied on more inefficient means to burn sugar for energy.

So in return for the ability to basically survive and become one of the most successful living organisms ever (mitochondria are found in nearly all complex living organisms) the other cells gained a far more efficient method of extracting energy from sugar.

This is all hypothesis and theory though. Since we have very little evidence from billions of years ago, it's really tough to say.

Answer 6

Mitochondrion...... small rod like or thread like organelle within the cytoplasm of cells. Functions in cellular respiration Provide the principle source ofcellular energy. Contains extra nuclear source of DNA, RNA polymerase, transfer RNA and ribosomes which are somehow involved in their replication.

Answer 7

My biology notes says that mitochondrial may be a degradation of an intracellular bacteria. Too much memory to tell the role of RNA. Go find wikipedia.

Answer 8

if i did, i wouldnt be here, i would be colecting a nobel prize or something.