New Finding! - A recent article said that mitochondrial DNA exhibits great diversity even in the same individual. This is a big surprise and has great significance in making of genetic markers as well as in the field of forensics.
The article says that different tissues are observed to have different mitochondrial DNA. They are not sure yet when this diversity become manifest.
Here is the link to this article.
http://www.the-scientist.com/blog/display/57199/
Showing posts with label mitochondrion. Show all posts
Showing posts with label mitochondrion. Show all posts
Thursday, March 4, 2010
Monday, January 5, 2009
energy generation in the mitochondrion, a summary
I have made this concept map to summarize all the processes of energy generation in the mitochondrion. I hope that you find it useful.
Saturday, January 3, 2009
Energy generation in the mitochondrion, part 2
source of image: www.britannica.com
As mentioned in yesterday’s post, the next 2 phases of energy generation in cells are Krebs’ cycle and oxidative phosphorylation.
Krebs’ cycle is also known as citric acid cycle because the first substrate formed is citric acid. This process occurs in the matrix of the mitochondrion.
This cycle is an 8-step process that changes AcetylCoA to citric acid and the latter into oxaloacetate. Main products of this cycle are Hydrogen ions and electrons which are immediately received by Hydrogen acceptors and transferred to the last phase or oxidative phosphorylation. By-products of this cycle are CO2 and H2O.
Only 2 ATPs are actually produced in the Krebs’cycle itself. However, since it is coupled with the last phase, oxidative phosphorylation, 22 more ATPs are produced through the coupled reactions.
We will talk about the last phase of this energy generation in tomorrow’s post.
Friday, January 2, 2009
Energy generation and the mitochondrion
Energy generation or cell respiration consists of 4 phases: glycolysis, conversion of pyruvic acid to Acetyl Coenzyme A, Krebs’ cycle and oxidative phosphorylation.
The last 3 phases of energy generation take place inside the mitochondrion while the first phase takes place in the cytoplasm of a cell.
Glycolysis is an anaerobic process (does not need oxygen to proceed) that involves breaking down of a sugar molecule (usually glucose) into 2 molecules of pyruvic acid. If oxygen is still not available after this process, then pyruvic acid is converted into lactic acid in animal cells and into ethyl alcohol in plant cells.
If oxygen is available however, the 2nd phase of energy generation takes place, that is, pyruvic acid is converted to Acetyl Coenzymne A in preparation for the 3rd phase of the process.
Glycolysis yields 4 molecules of ATP (the energy currency of cells) but the net yield is only 2 molecules of ATP because 2 molecules are used up to prepare glucose for the process. On the other hand, phase 2 or the conversion of pyruvic acid to AcetylCoA yields a net of 6 ATP molecules.
The last 2 phases of cell respiration are coupled. That is, one cannot occur without the other. We will thus talk about these 2 in another post.
The last 3 phases of energy generation take place inside the mitochondrion while the first phase takes place in the cytoplasm of a cell.
Glycolysis is an anaerobic process (does not need oxygen to proceed) that involves breaking down of a sugar molecule (usually glucose) into 2 molecules of pyruvic acid. If oxygen is still not available after this process, then pyruvic acid is converted into lactic acid in animal cells and into ethyl alcohol in plant cells.
If oxygen is available however, the 2nd phase of energy generation takes place, that is, pyruvic acid is converted to Acetyl Coenzymne A in preparation for the 3rd phase of the process.
Glycolysis yields 4 molecules of ATP (the energy currency of cells) but the net yield is only 2 molecules of ATP because 2 molecules are used up to prepare glucose for the process. On the other hand, phase 2 or the conversion of pyruvic acid to AcetylCoA yields a net of 6 ATP molecules.
The last 2 phases of cell respiration are coupled. That is, one cannot occur without the other. We will thus talk about these 2 in another post.
Thursday, January 1, 2009
Mitochondrion
source of image: www.britannica.com
I thought a good way to start the New Year right is to talk about cell energy and the mitochondrion.
The mitochondrion is an organelle that is involved in energy production. It is a rather complex organelle, it will probably take a few posts to completely its story.
Anyway, just to get started, let’s first talk about its structure today.
A mitochondrion (plural, mitochondria) is usually rod-shaped but this shape can change at anytime under varying conditions. It has a double membrane, the outer one being smooth and the inner one being thrown into folds called cristae (sing. crista). These folds increase the area for enzymes embedded in it and the more active a cell is, the more folds there are. Thus, a heart muscle cell for example has more cristae in its mitochondrion compared with a cartilage cell's mitochondrion.
There is a narrow space between the outer and inner membranes of the mitochondrion. This space is called the intermembrane space. Another space is found in the middle of the mitochondrion and this is called the matrix space or simply the matrix. Contents in both spaces differ.
The contents of the intermembrane space are somewhat similar to that of the cytosol whereas the matrix space contains many enzymes involved in the Kreb’s cycle process. Ribosomes as well as a circular DNA and tRNA are also found in the matrix.
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