Download Why do cells need to divide?

Cell Cycle
all cells need to grow and divide.
there are two main stages of the life of a cell
growth stage = interphase
division stage = mitosis and cytokinesis
division
stage
growth
stage
Why do cells need to divide?
growth
replace
repair
(regeneration)
1
DNA
DNA is the hereditary material that is passed on
during cell division.
DNA contains all the instructions that determine all
the details of the cells life.
DNA is stored in the nucleus
DNA is very long and must pack together tightly
when a cell divides
DNA packed tightly forms a chromosome
Mitosis clips
Cell Division
http://www.teachersdomain.org/resource/lsps07.sci.life.stru.celldivision/
Mitosis Video 1
http://www.teachersdomain.org/resource/tdc02.sci.life.stru.dnadivide/
Mitosis Video 2
http://videos.howstuffworks.com/hsw/17710­mitosis­and­meiosis­mitosis­video.htm
2
Interphase
the cell grows and carries out its normal functions
it makes a copy of it organelles
it makes a copy of its DNA to prepare for division
page 29 in 2P book
Prophase
the nuclear membrane begins to disappear
the duplicated DNA condenses into chromosomes
that are visible under the microscope
the duplicated chromosome is made up of two
identical copies of DNA that are joined together
at one point.
3
Metaphase
spindle fibres in the cytoplasm push the duplicated
chromosomes
the duplicated chromosomes line up at the middle of
the cell
Anaphase
The duplicated chromosomes split apart,
separating the identical copies of DNA.
Each part is now called a chromosome
4
Telophase
Each nucleus has has a complete set of
chromosomes
Membranes
nuclei
begin to form around the new
the chromosomes begin to uncoil.
Cytokinesis
the cell pinches and divides the cytoplasm
into two parts
two identical separate cells are
formed
5
Cells remain in interphase:
• enough nutrients?
• enough organelles?
• enough cytoplasm?
• did the DNA replicate?
• is the DNA damaged?
• signal from neighbors not to.
6
Attachments
Cell Divison grade 10.ecw
2D Mitosis fill in the blanks worksheet.doc
Mitosis fill in the blanks worksheet.doc