Cell Reproduction Chapter 4. Cell Growth and Division Chapter 4-1 Cells undergo division to:...
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Transcript of Cell Reproduction Chapter 4. Cell Growth and Division Chapter 4-1 Cells undergo division to:...
Cell Reproduction
Chapter 4
Cell Growth and DivisionChapter 4-1
Cells undergo division to: Increase in number Repair worn out cells Replace cells that have died
Cell cycle
Interphase – most of the life of any cell period of growth and
development DNA replication growth and preparation for
mitosis Nerve and muscle cells
don’t divide remain in interphase
Skin cells constantly change
Mitosis
The process in which the nucleus divides to form two identical nuclei.
It is a series of phases or steps.
Animal Mitosis
Interphase – Nucleus can be seen DNA is replicating
(making exact copies)
Prophase – Chromosomes visible Nucleolus and nuclear
membrane fade Centrioles move to
opposite end of cell Spindle fibers begin to
stretch across the cell
Metaphase- Double strands of
chromosomes line up across the center of cell
Attach to a spindle
Centromere – place where double stranded chromosomes are held together
Anaphase
Anaphase Centromeres divide Two strands separate Separate strands move
away toward opposite ends of cell
Telophase Centrioles and spindles
disappear Chromosomes stretch
out and become harder to see
Nuclear membrane forms around each mass of chromosomes
New nucleolus appears Cell begins to split by
pinching at cell membrane
Daughter cells – new cells that divided from a parent cell
Interphase
Mitosis
Mitosis in Plant Cells
All phases are the same as animal cells
Telophase Cell wall is produced
to separate the cells.
http://www.biology.arizona.edu/cell_bio/activities/cell_cycle/cell_cycle.html
Identify each phase of mitosis below.
Identify animal mitosis
Results of Mitosis
Two Important results of mitosis: Nucleus was divided Two new nuclei are identical
CytokinesisThe period of the cell cycle when the cell separates into two daughter cells
Animal cell cytokinesis – cell membrane pinches in the middle and a new membrane is formed
Plant cell cytokinesis – cell wall is formedbetween the two daughter cells, then a cell membrane forms and completely separates.
.