Thursday, December 18, 2008

Dying Before Their Time

This observation has made many species has prompted some researchers to conjecture that the increasing burden of mutations in mitochondrial DNA is a cause of aging. The majority of researchers have thought otherwise. They argue that the mutations are molecular consequences of aging, akin to wrinkles and graying hair. At some early point in the history of life, two microscopic cells—most likely different kinds of bacteria—apparently struck a complex bargain. One provided a safe, comfortable home inside its own cellular membrane. Mitochondria are the power plants of an animal cell. Some energy-hungry cells, such as those in muscles, contain up to a thousand of these remarkable organelles. Instead of making electricity, as conventional power plants do, mitochondria use oxygen and complex sugars in a process known as respiration. The product is an energy-rich molecule, adenosine triphosphate (ATP), which cells use to drive myriad chemical reactions. Without ATP, cells would be powerless and die. Highlighting the potential importance of mtDNA mutations, Samuels reports in the May Trends in Genetics that the vulnerability of mtDNA to deletions may constrain the maximum life span of most mammals to 80 to 100 years. Analyzing previously reported mtDNA sequences of 61 mammalian species, he considered the number of DNA repeats, which are nucleotide sequences that occur twice in close proximity along a DNA molecules. Such repeats mark areas of mtDNA that tend to get deleted with age.

I think this study is a very good one because it will make you not die before your time to go. We have been learning about adenosine triphosphate and with this story it got me thinking more about it. I learned a lot more about adenosine triphosphate with this story. It has got me to were I will answer more questions in class about adenosine triphosphate than I was before now. It teaches you more about the mitochondria.

1. Conjecture- An opinion or conclusion formed on the basis of incomplete information.
2.Myriad- A countless or extremely great number.
3. Vulnerability- Susceptible to physical or emotional attack or harm.
4. Surmises- Suppose that something is true without having evidence to confirm it.
5. Circumstantial- Pointing indirectly toward someone's guilt but not conclusively proving it.

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