What is a cell?
The body consists of cells. Each cell of the body has a cell membrane and in each cell is DNA and proteins. What about the actual situation? And how does it work?
What is a cell?
Whole body composed of cells
The whole body is composed of cells. There are many different cells in the body, and each cell has its own task. Sometimes a group of cells with another group of cells the same and we call it an institution. Like an orange. Each slice consists of small cells. Actually, the cell can best be described as a colony of wasps. Each wasp has its own task, and sometimes there are groups that do the same. There are workers and there are females that take care of the larvae and a queen who makes the offspring. Together they are a great whole and they can not live without each other.
Membrane composed of phospholipids
There are some similarities between the cells. The cells from the brains, liver and heart all have a cell membrane. It is made of phospholipids. A phospholipid is a type of fat. It is a glycerol molecule, which carries a phosphate group and two fatty acids. The fatty acid with the COOH group (see What is an acid? ) bound to the glycerol. The two oxygen atoms of the fatty attract electrons to itself a bit. We call this polar: if the charge is not quite right about the molecule is divided. If the electrons prefer to oxygen atoms, which are a bit negatively charged. Not quite, because the electrons are not quite at the oxygen atoms, but a little. The phosphate group is charged and thus provides an even greater polar character of the phospholipid. The head of the molecule is polar, the tails of the fatty acids, not. Polar molecules like to sit in water. Water is polar, two polar compounds and would like to be together. If you submit a drop of water on phospholipids, the heads go in the water and feet remain together in the interior of the droplet. This is called a micelle. A cell membrane as a whole really needs to feel comfortable in water. Therefore a second layer formed from phospholipids. This is called a bilayer. The heads of the phospholipids on the outside, the inside legs.
Transport across the cell membrane
The cell has a membrane around it that is like water (and it should be, because blood is a liquid based on water) but from within like fatty substances. This allows various fat-soluble substances in the membrane. For substances not so much like the cell, there are mechanisms by which it succeeds anyway. A flip flop or a pump for example sodium channel. The flip flop pump does exactly what you think he does: it binds a substance itself and turns to dust and all over the cell membrane, the cell. The CD36/FAT vetreceptor for example, uses this mechanism to the cell to get fat. The sodium channel allows sodium into the cell. However, sodium is positively charged, and the cell will always remain neutral. So there will be another positively charged substance to the cell. That may be potassium. The sodium pump is actually called sodium / potassium pump. Sodium and potassium can not pass through the same channel, because potassium is much greater. In the periodic table of elements is a row of lower potassium than sodium, which means that a whole lot bigger.
In each cell's DNA and proteins
Every cell in your body has the same DNA (see What is DNA? ). But not in every cell are the same genes. Liver cells have functions other than brain cells and therefore require other proteins. The proteins control your body. They are put on or off because there is hung a phosphate group and therefore they perform a certain task. Most cells in your body also, except nerve cells, which do not divide. This is not a cure SCI. The damaged nerve cells can not be replaced by new shares arising from other neurons. When a cell divides, the new cell DNA again. It is made by DNA polymerase, which ensures that the DNA is completely copied. This copy is sometimes wrong. The stop signal hits each. Then shall the cell is not as often as needed, but continues to share if there are enough new cells. A tumor may arise. So when the tumor cells become detached from and going somewhere else to grow, creates metastases. Tumors treated with chemotherapy with cytotoxic drugs. That means making it static, so stopping cyto, another word for cell. The tumor cells divide rapidly, faster than most other cells in the body. Intestinal cells and hair cells divide quickly. This makes the intestines and hair are most affected by the chemotherapy, in addition to the tumor.
Aging
A cell can only a limited number of parts. Then it stops and the body can no longer regenerate. As a result, old people. The skin renews itself no more, the heart can go fail in its operation, liver and kidneys it increasingly difficult to continue to function properly. And finally there to keep all cells. And the body also.
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