1. Mitosis: Cell Division

2. New cells are produced:
for growth
to replace damaged or old cells
For asexual reproduction in some organisms

3. Interphase – cell copies DNA and prepares for division
Cell Division - process by which a cell splits into two identical daughter cells
*Occurs in two main phases: 
Interphase – cell copies DNA and prepares for division
Mitosis – chromosomes separate into two new cells

4. What are chromosomes? DNA containing cell’s genetic code
Each chromosome has a matching pair (homologous)
During interphase, each chromosome copies itself

5. Life Cycle of the Cell Mitosis = nuclear division
Mitosis is followed by cytokinesis (cell division)
The steps of mitosis ensure that each new cell has the exact same number of chromosomes as the original
Interphase = growth phase, differentiation occurs

6. DNA Replication DNA must be copied before cell division
Each new cell will then have an identical copy of the DNA
Happens during the S (synthesis) phase of cell cycle

7. The Cell Cycle Interphase (longest phase)
G1 - first growth (gap) phase
Synthesis - DNA makes a copy
G2 - second growth (gap) phase, preparing for mitosis
Mitosis - nucleus divides, ensuring each new cell has the exact number of chromosomes as parent

8. Uncontrolled Cell Division
If the cell cycle is not controlled, cell division does not stop and forms tumors.
Cancer is uncontrolled cell division
Cancer cells

9. Uncontrolled Cell Division
Cancer cells do not carry out necessary functions.

10. One chromosome comes from the mother, the other comes from the father.
Definitions
Homologous chromosomes a pair of chromosomes that are similar and carry genes for the same traits
One chromosome comes from the mother, the other comes from the father.

11. Diploid vs. Haploid
diploid (2n) cells have a full set of chromosomes - pairs of homologous chromosomes.
haploid (n) cells are Sex cells or gametes and have ½ the diploid number of chromosomes - one chromosome from each homologous pair.

12. MITOSIS
Mitosis is
Cell division that begins with 1 diploid cell and ends with 2 diploid cells
Asexual reproduction

13. Interphase • Prophase • Metaphase • Anaphase • Telophase
IPMAT

14. 1. chromosomes visible (chromatids)
2. centrioles migrate to the poles
3. nuclear membrane disappears
4. spindle forms

15. 1. chromosomes line up on the equator, spindle attaches

16. 1. chromatids separate and move to opposite poles

17. 1. chromosomes unwind
2. nuclear membrane reforms
3. spindle disappears

18. - division of the cytoplasm to form 2 new daughter cells
- organelles are divided
- daughter cells are genetically identical
Cells return to interphase

25. Name the phases starting at the top.

26. Name the phase
Identify X
Identify Y

27. 5. Name the phase

28. 6. Name the phase

29. Meiosis is the formation of gametes or sex cells (egg and sperm)
Meiosis II
Diploid
Haploid

30. Meiosis Forms Haploid Gametes
Meiosis is cell division that reduces the number of chromosomes.
from mom
from dad
child
too
much!
meiosis reduces
genetic content
The right number!

31. It begins with one diploid cell and ends with 4 haploid cells.
Meiosis
It begins with one diploid cell and ends with 4 haploid cells.
Meiosis is part of sexual reproduction.
Fertilization is when two haploid gametes join to form a diploid zygote.

32. Crossing-Over Homologous chromosomes cross over each other in meiosis
Pieces of chromosomes or genes are exchanged
Produces Genetic variation in the offspring

33. Karyotype A picture of chromosomes arranged in pairs
First 22 pairs are called autosomes
Last pair are the sex chromosomes
XX female or XY male

34. The Y Chromosome Decides
Boy or Girl?
The Y Chromosome Decides
Y - Chromosome
X - Chromosome

35. Comparing Mitosis and Meiosis

36. Comparison of Mitosis and Meiosis
REPRODUCTION TYPE
PURPOSE
# CELLS START
# CELLS END
CHROMOSOMES START (haploid/diploid)
CHROMOSOMES END (haploid/diploid)
sexual
asexual
Grow, repair, reproduction (in some organisms)
Produce gametes 1 1 4 2
diploid
diploid
diploid
haploid

37. Phases of mitosis

38. Asexual & Sexual Reproduction
CELL DIVISION
Process
Advantages
Genetic Variation
mitosis
meiosis
Produces haploid gametes that join to form a diploid zygote
Produces identical diploid cells
Not identical to parent
Un-wanted traits might not be passed on
Needed traits for adaptation are passed on
Good in changing conditions
Identical cells are produced
Only one parent
good in unchanging conditions No
Yes

39. Pop Quiz / Exit Ticket D