Re: how do the mitochondria and the nuclei communicate with eachother?

Date: Wed Jan 17 14:56:28 2007
Posted By: Kevin, Grad student, Dept. of Chemistry and Biochemistry, George Mason University
Area of science: Cell Biology
ID: 1168991007.Cb

Message:
Almost every cell in the human body has the same DNA so the DNA in the mictrochondria is the same as the DNA in the nucleus. Different genes are expressed in different cells which account for the diversity we observe in cells. The stomach cells for example would transcribe the set of genes responsible for production beta-galactosidase which is needed to break lactose down after dairy consumption. This set of genes would not be needed in say a kidney cell and therefore is not expressed. It would be a tremendous waste of energy for our bodies to express all genes, proteins etc. in all of our cells. We only express what we need (unless you want to get technical and get into cancers and mutations etc.)

I molecule of ATP is worth ~ -20.5 KJ, that is the reaction: ATP --> ADP + Pi gives off 20.5 KJ

I am not familiar with mitochondrial disease's but I found this site; http://www.umdf.org/mito_info/whatismito.aspx

Check it out. I hope this helps. Take care and good luck with the cell bio!!

Kevin Jarboe
George Mason University
Department of Chemistry & Biochemistry

[Moderator's Note: The DNA found in the mitochondrion is quite different from the DNA in the nucleus. The nuclear genome consists of two copies of 23 linear chromosomes which total 3 billion nucleotides of sequence, and contains around 20,000 genes. The mitochondrial genome consists of hundreds or even thousands of copies of a single circular chromosome that is only 16,569 nucleotides long and contains 37 genes. The products of these mitochondrial genes are specific to the electron transport and respiration functions of the mitochondrion. For more information, take a look at these answers in our archives:
http://www.madsci.org/posts/archives/2005-05/1115222012.Ev.r.html

http://www.madsci.org/posts/archives/feb98/887302952.Ge.r.html

http://www.madsci.org/posts/archives/mar98/890683118.Cb.r.html

While beta-galactosidease does catalyze the hydrolysis of lactose, this enzyme is not produced by humans (or animals, for that matter). Instead, we produce the enzyme lactase, which is specific for the hydrolysis of lactose. In addition, lactase is not expressed in the stomach; it is expressed in the samll intestine. For more information, take a look at these answers in our archives: http://www.madsci.org/posts/archives/2005-03/1110993926.Ev.r.html

http://www.madsci.org/posts/archives/2005-09/1127696633.Ev.r.html

http://www.madsci.org/posts/archives/2005-04/1114114022.Gb.r.html

And this page about gene expression in the small intestine:
http://www.vivo.colostate.edu/hbooks/pathphys/digestion/smallgut/ontogeny.html

Finally, the free energy of hydrolysis of ATP to ADP + phosphate is between 7.2 and 7.3 kilocalories per mole. This translates to between 30.1 and 3.5 kilojoules per mole. For more information, review the pertinent section of a college-level biochemistry textbook, for example Biochemistry, by L. Stryer.

-- SM]

Current Queue | Current Queue for Cell Biology | Cell Biology archives

Try the links in the MadSci Library for more information on Cell Biology.