OK, so it's been a while since I last posted. In the lapse I managed to remove the film of flour which settled over my kitchen after three days of holiday cookie baking, finish Christmas shopping and distribute gifts accordingly, and take down all of the Christmas decorations and tree. At least I've been productive these past two weeks
Meanwhile, I've been reading the cleverly titled Power, Sex, Suicide: Mitochondria and the Meaning Of Life by Nick Lane. It's not a new book- it was first published in 2005, although the first time I heard about it was last year when my biochemistry teacher mentioned it in class. It has been a great read so far so I figured I'd mention it here for anyone who is interested.
In Power, Sex, Suicide, Nick Lane discusses the importance of mitochondria and their role in evolution. Lane echoes a sentiment shared by many scientists- that mitochondria were crucial to the development of complex multi-cellular organisms, and that without them, the Earth would be teeming with single-celled bacteria.
At some point in evolution, millions of years distant, an alpha proteobacteria was incorporated into a larger cell- evidence suggests that the host may have been a methanogen, one of the single-celled archaea - and since then, the two have been inseparable. In the sequence of events that led to their union everything had to happen at just the right time, and in just the right way, to foster the relationship which has endured millions of years of evolution. Although mitochondria have retained most of their own DNA and protein making machinery, some mitochondrial genes have made their way into nuclear DNA, essentially trapping the mitochondria within its eukaryotic host. Lane discusses research concerning the origins of the mitochondrial-eukaryotic cell partnership and the theories which have been constructed from the data.
Mitochondria are often aptly referred to as the 'powerhouse of the cell', and play an essential role in keeping cellular processes running smoothly by providing the cell with 'energy' in the form of ATP (Adenosine triphosphate). ATP is considered the 'energy currency' of the cell. Cellular respiration occurs in the mitochondria, which function as tiny molecular factories churning out ATP molecules. The ATP produced by mitochondria are then used to drive a number of intracellular processes, including transport of proteins and other molecules throughout the cell and across the membrane, synthesizing messenger RNA from a DNA template, and building new proteins from the 'instructions' encoded in the messenger RNA.
Mitochondrial defects can be catastrophic to energy production within the cell, and they can also lead to the development of various diseases or misregulation of apoptosis, otherwise known as 'cell suicide'. Normally, when something goes wrong inside a cell or it is defective in some way, mitochondria begin the process of destroying the aberrant cell. One abnormal cell could potentially be dangerous to neighboring cells or to the organism which it is a part of.
Cancerous tumors sometimes arise as a result of the failure to inititiate cell suicide- a cell which has acquired deleterious novel mutations should be destroyed immediately; however, if cell suicide is disrupted the mutant cell may become immortalized or gain the ability to divide unchecked. Uncontrolled cell division may then produce a cancerous tumor which can often be lethal.
I could go on for quite a while about the importance of these microscopic generators- say about how injection of 'fresh' mitochondria apparently boost the efficacy of in vitro fertilization in women who are otherwise having trouble concieving- because I find them fascinating, but maybe I should just leave the rest to you, reader. I highly recommend this book to anyone looking to find out more about the mystery of mitochondria!