2. Mitosis
The parent cell splits to produce two IDENTICAL daughter cells…
each with the same number of chromosomes as the parent
(46 chromosomes in humans)
Asexual Reproduction
Binary Fission
EVERY cell in your body is doing it!

3. chromosomes duplicate
parent cell
chromosomes duplicate
chromosome pairs line up at middle of the cell
chromosome pairs are pulled apart… and go to opposite ends of the cell
cell divides into two identical daughter cells

4. Meiosis Parent cell splits twice to produce four SEX cells …
each with half the chromosomes of the parent
(23 chromosomes in humans)
ONLY special cells do it… they make gametes.

5. PART 1 PART 2 parent cell chromosomes duplicate
chromosomes exchange some genetic information
chromosomes line up in middle, and pull towards ends
cell divides into two cells (not identical to parent)
chromosomes line up in middle & pull towards the ends of each cell
each cell divides… producing 4 sex cells… each with ½ chromosomes as parent cell
PART 2

6. Sexual Reproduction Zygote Embryo female gamete: male gamete:
egg with ½ chromosomes
male gamete:
sperm with ½ chromosomes
fertilization:
egg with full set of chromosomes
Zygote
mitosis takes over and cells reproduce
Embryo
Questions:
What type of reproduction is shown at the top of the diagram?
How many chromosomes in EGG… SPERM… ZYGOTE
How many chromosomes in each of the different types of blood cells?
What type of cell division will occur to replicate bone cells?.... nerve cells?
How many chromosomes are present in blood cells?... in gland cells?... in a cell in your stomach?
DNA tells each cell what to be and what to do

7. Mitosis Meiosis 1 division 2 divisions 2 offspring cells
offspring cells genetically identical
offspring cells have = chromosomes as parent
used in ALL cells
for growth, repair, asexual reproduction
Meiosis
2 divisions
4 offspring cells
offspring are genetically different
offspring cells have 1/2 chromosomes of parent
used ONLY to produce sex cells

8. Check your chromosome math…