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Science Mitosis

Terms in this set (29)

Why do cells divide?
Cell division allows you to grow and replace cells that have died. ex cuts and bruises heal, red blood cells are produced at the rate of 2 billion new cells per second
Cell Cycle
the ______ _____ begins when the cell is formed and ends when the cell divides and forms new cells
Prokaryotic cells
Some of these are bacteria. Uses Binary Fission
Binary Fission
Cell division in bacteria. This means simply "splitting into two parts." This is a very simple process
DNA
before a cell divides, it must make a copy of its ______________________
Chromosomes
The DNA of a cell is organized into structures called ______. X shaped structures in the nucleus that contain all of the genetic information for an organism. Copying these ensures that each new cell will be an exact copy.
Interphase
Most of a cell's life cycle is spent in this. a period of rapid growth and development.
What happens during interphase
Rapid growth
preparation for cell division (chromosomes are doubling)
Chromatin
During Interphase, _______ masses of DNA and protein found in the nucleus, is very busy. It actively duplicates itself.
Animal Cell Mitosis
Only a small part of a cell's life span is actually spent in cell division.
2 parts of cell division
Mitosis and Cytokinesis
Mitosis
first the nucleus divides - the division of the neucleus into 2 new nuclei is called _____
Cytokinesis
After mitosis the cytoplasm divides - the division of the cytoplasm is called ________
4 stages of mitosis
1. Prophase
2. Metaphase
3. Anaphase
4. Telophase
Prophase
the chromatin thickens and becomes visible as chromosomes. The nuclear membrane dissapears
Centromeres
The chromosomes are held together by _______. The point at which 2 chromatids are attached to form a chromosome
Chromatids
are one strand of a double-stranded chromosome or "half of an X"
Centrioles
Poles at either end of the cell that send out spindle fibers during cell division- form at opposite ends of the cell
Spindle Fibers
finger like projections sent out from the centrioles to pull the chromosomes apart - begin to stretch across the cell
Metaphase
the chromosomes line- up across the middle of the cell
each centromere is attached to a spindle fiber
Anaphase
the centromeres divide

the double-stranded chromosomes separate to form chromatids

the separated chromatids more towards opposite ends of the cell
Telophase
the centrioles and spindle fibers disappear

chromosomes become harder to see as they revert back to chromatin

the nuclear membrane reappears

the cell membrane pinches inward ad the cytoplasm divides between the 2 new nuclei. (cytokinesis)
End of mitosis
Once mitosis is complete, two new cells(daughter cells) are formed. These are exact copies (identical) of the parent cell that is the original cell. The daughter cells have the same number of chromosomes as the parent. In human body cells, this mumber is 46 chromosomes.
Plant cell mitosis
Cells have rigid cell walls. Therefore they cannot pinch inward like animal cells. Instead of pinching apart, a cell plate forms. The real new cell wall forms along this cell plate
Cell Plate
it is the beginning of a new cell wall that forms between 2 the new nuclei in a plant cell.
Prophase
Metaphase
Anaphase
Telophase
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