Chromosomes and Mitochondria
Human have 23 pair of chromosomes. Why are human chromosomes in pair? Chromosomes that pair one another are known as homologous. Homologous means that the chromosomes have the same length and their centromeres are in the same position, they show the same pattern of light and dark bands when stained, and they carry genes for the same inherited characteristics, line up on the chromosome in the same order.
Out of 23 pair of chromosomes, only male sex chromosomes are heterogeneous because they have chromosome XY while female has a matching pair which is XX. It is the Y chromosome that is of major interest to the genealogist because, as it is handed from father to son, virtually unchanged, it becomes a signature or fingerprint for the surname which is passed down in the same way in many cultures.
Now, you have learned something about human chromosomes but chromosome is not only the pieces that contain DNA. Now we are going to talk about Mitochondria which also contain DNA important for cell growth.
Mitochondria are extremely small, ranging from 0.002 to 0.008 millimeters in length whose details can only be seen with the electron microscope. Mitochondria are the power plant in our cell to generate energy for reaction and metabolism to take place. I give you an instance involving the job of Mitochondria in human cell. When you eat carbohydrate, it is broken down and finally converted to glucose. Mitochondria release the energy from glucose to power our cell.
Mitochondria contains small amount of DNA which is used to direct the manufacture of thirteen of the proteins needed for its activities. Mutations in the protein coding part of mitochondrial DNA can cause some human diseases, typically involving either neuromuscular dysfunction or some forms of diabetes.
Of interest to the genealogist (among others) is the fact that all of an individual’s mitochondria are derived from his/her mother. Although the sperm cell tail is packed with mitochondria to power its long journey to the egg cell, the tail and mitochondria drop off of the sperm at fertilization and never enter the egg cell. Consequently, all of the mitochondria in the fertilized egg come from an individual’s mother.
Each cell contains thousands of copies of mitochondrial DNA but only one paired set of chromosomal DNA.
Out of 23 pair of chromosomes, only male sex chromosomes are heterogeneous because they have chromosome XY while female has a matching pair which is XX. It is the Y chromosome that is of major interest to the genealogist because, as it is handed from father to son, virtually unchanged, it becomes a signature or fingerprint for the surname which is passed down in the same way in many cultures.
Now, you have learned something about human chromosomes but chromosome is not only the pieces that contain DNA. Now we are going to talk about Mitochondria which also contain DNA important for cell growth.
Mitochondria are extremely small, ranging from 0.002 to 0.008 millimeters in length whose details can only be seen with the electron microscope. Mitochondria are the power plant in our cell to generate energy for reaction and metabolism to take place. I give you an instance involving the job of Mitochondria in human cell. When you eat carbohydrate, it is broken down and finally converted to glucose. Mitochondria release the energy from glucose to power our cell.
Mitochondria contains small amount of DNA which is used to direct the manufacture of thirteen of the proteins needed for its activities. Mutations in the protein coding part of mitochondrial DNA can cause some human diseases, typically involving either neuromuscular dysfunction or some forms of diabetes.
Of interest to the genealogist (among others) is the fact that all of an individual’s mitochondria are derived from his/her mother. Although the sperm cell tail is packed with mitochondria to power its long journey to the egg cell, the tail and mitochondria drop off of the sperm at fertilization and never enter the egg cell. Consequently, all of the mitochondria in the fertilized egg come from an individual’s mother.
Each cell contains thousands of copies of mitochondrial DNA but only one paired set of chromosomal DNA.
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Great article!
So the mitochondria has 1 paired set of chromosomes with 37 genes?