a) Mitochondria are the power plants of the cell. They provide energy, or ATP, for the cell through a process called oxidative phosphorylation. Without mitochondria, our cells would not be able to perform tasks necessary to live. Unlike the rest of the cell's organelles, mitochondria have their own unique set of DNA. One theory for why this is that mitochondria were once bacteria cells that became incorporated in a symbiotic relationship with eukaryotic cells. Mitochondria and bacteria are about the same size and both have similar, simple functions.
It is known that mitochondrial DNA can be traced back through the mother of each generation. A woman's egg contains all the organelles necessary for the embryo to survive, including all the mitochondria. A man's sperm has a lot of initial energy, but lacks mitochondria (thus, they eventually die). This way, when fertilization occurs and a baby is eventually born, all of the baby's mitochondria (and the mitochondrial DNA) were originally from the mother. This knowledge proves very useful for paternity testing and tracing family lines back for centuries.
b) The purpose of this lab is to extract our mitochondrial DNA and analyze it/compare it with other people at our lab table.
c) We will be using many similar techniques as the previous DNA extraction and "disease" testing lab. First, we will extract DNA from our cheek cells, using a saline mouthwash. Then we will concentrate the cells via centrifuge and add Chelex to the solution (Chelex binds to the ions released from the cells which inhibit PCR, thus allowing PCR to occur). The cheek cells will be lysed open via a hot water bath, releasing all the DNA. We will then add primers which specifically target a gene from the mitochondrial DNA. That way, when we run the DNA through PCR, only the mitochondrial gene will be amplified. Lastly, we will run the amplified DNA through gel electrophoresis so that we can get a visual on the DNA and compare our DNA results with the results of other people.
d) Since this lab is more of a comparison/knowledge activity than an experiment, there are no variables or controls. You could say the DNA is a variable, because obviously each person's DNA is different. However, we do not have a "control" gene to compare it to, so it makes no difference.
c) We will be using many similar techniques as the previous DNA extraction and "disease" testing lab. First, we will extract DNA from our cheek cells, using a saline mouthwash. Then we will concentrate the cells via centrifuge and add Chelex to the solution (Chelex binds to the ions released from the cells which inhibit PCR, thus allowing PCR to occur). The cheek cells will be lysed open via a hot water bath, releasing all the DNA. We will then add primers which specifically target a gene from the mitochondrial DNA. That way, when we run the DNA through PCR, only the mitochondrial gene will be amplified. Lastly, we will run the amplified DNA through gel electrophoresis so that we can get a visual on the DNA and compare our DNA results with the results of other people.
d) Since this lab is more of a comparison/knowledge activity than an experiment, there are no variables or controls. You could say the DNA is a variable, because obviously each person's DNA is different. However, we do not have a "control" gene to compare it to, so it makes no difference.
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