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Cell Division
p. 46 -48
Binary Fission
•Used by Unicellular Organisms to reproduce
Asexually, resulting in genetically identical
offspring
•One parent = genetically identical offspring
•Instead of just splitting exactly in half (and creating
an individual with only half the DNA make up
needed)
•The cell makes a copy of its genetic material and
then divides
•This creates an exact copy with all of the DNA
material needed
For this stage the parent has twice
the amount of DNA it usually has
Mitosis
• Like Binary Fission, cells of the body in a multicellular organism
replicate in a process called Mitosis
• Mitosis: A type of cell division that produces two identical daughter
cells from one parent cell
• The parent makes an exact copy of DNA
• Produces two cells with the same number of chromosomes as a
parent
• Occurs in body cells and is responsible for GROWTH and CELLULAR
REPAIR
Mitosis
Stages of Mitosis
Meiosis
• We know that in Sexual Reproduction the male
produces a gamete called a sperm cell, and the
female produces a gamete called an Ova that
come together to form in a process called
fertilization to create a zygote.
• If both of these gamete cells contained the full
amount of DNA, then the zygote would contain
92 Chromosomes instead of 46
• That’s double what it can have
• To make sure our body has the correct amount
of DNA our reproductive cells use a different
type of cell division called Meiosis
Meiosis
• Cellular replacement of reproductive cells
(gametes)
• It involves two cell divisions
• A first Cell division takes place, where the
pairs of chromosomes are duplicated (like
in Mitosis)
• Then a second division occurs without
duplication of Chromosomes
• Resulting in 4 gametes (sex cells)
• These contain ½ the DNA of parent
• Crossing over of genetic material can also
occur, this process is responsible for the
variation amongst the different
chromosomes (switch genes)
Mitosis
Meiosis