Chapter 10 Cell Growth and Division. Cell Growth. A. A living thing grows because it produces more and more cells. 1. The cells of a human adult are no larger than the cells of a human baby, but there are more of them.
A. A living thing grows because it produces more and more cells.
1. The cells of a human adult are no larger than the cells of a human baby, but there are more of them.
3. Cell division is the process whereby the cell divides into two daughter cells.
1. Cells can grow very fast.
3. Bacteria will grow and grow and then split in half into two identical cells.
6. The process by which a cell divides into two new daughter cells is called cell division.
A. The first stage of cellular division in Eukaryotes is called mitosis. The second stage is called cytokinesis.
1. In Eukaryotic cells, chromosomes carry the genetic information that is passed on from one generation of cells to the next.
6. Well before cell division, each chromosome is replicated, or copied.
1. The cell cycle describes the life of a Eukaryotic cell.
2. The cell cycle is a repeating sequence of cellular growth and division during the life of an organism.
4. First growth (G1)phase- a cell grows rapidly and carries out its routine functions. Cells that are not dividing remain in the G1 phase.
7. Mitosis- The process during cell division in which the nucleus of a cell is divided into two nuclei.
1. If a cell spends 90% of its time in interphase, how do cells “know” when to divide?
2. Cell Growth (G1) checkpoint-This checkpoint makes the key decision of when the cell will divide or not.
4. Mitosis check point- will trigger the exit from mitosis.
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Interphase (not really a phase)
A. Controls on cell division.
1. Scientists can observe the effects of controlled cell growth in the lab by placing some cells in a petri dish.
3. Most cells will grow until they form a thin layer covering the bottom of the dish. (see page 250) Then the cells stop growing.
5. The same thing happens in the body to repair from an injury.
1. For many years scientists are looking for something that can regulate the cell cycle.
4. It was also discovered that there are two types of regulator proteins 1- those that occur inside of the cell and 2- those that occur outside of the cell.
1. Proteins that respond to events inside the cell are called internal regulators.
2. Internal regulators that allow the cell cycle to proceed only when certain processes have happened inside of the cell.
1.Proteins that respond to events outside the cell are called external regulators.
2. External regulators direct ells to speed up or slow down the cell cycle.
4. They stimulate the growth and division of cells.
5. Growth regulators are very important in embryonic development and wound healing.
1.Why is cell growth regulated so carefully?
2.Cancer is a consequence of uncontrolled cell growth.
3. Cancer is a disorder in which some of the body’s own cells lose the ability to control growth
5. As a result, they divide uncontrollably and form masses of cells called tumors that can damage the surrounding tissues.
7. There are certain carcinogens that can cause this to happen. Such as: tobacco, radiation exposure, and even a viral infection.