1. Cell Division and Mitosis
Chapter 5c
Cell Division and Mitosis

2. Prokaryotic organisms
Division Mechanisms
Eukaryotic organisms
Mitosis
Meiosis
Prokaryotic organisms
Prokaryotic fission`

3. Roles of Mitosis 1) Multicelled organisms a) Growth
b) Cell replacement
2) Some protistans, fungi, plants, animals
a) Asexual reproduction`

4. Chromosome 1) A DNA molecule & attached proteins
2) Duplicated in preparation for mitosis`
one chromosome (unduplicated)
one chromosome (duplicated)

5. Chromosome Number 1) Sum total of chromosomes in a cell
2) Somatic cells
a) Chromosome number is diploid (2n)
b) Two of each type of chromosome
3) Gametes
a) Chromosome number is haploid (n)
b) One of each chromosome type`

6. Human Chromosome Number
1) Diploid chromosome number (n) = 46
2) Two sets of 23 chromosomes each
a) One set from father
b) One set from mother
3) Mitosis produces cells with 46 chromosomes--two of each type`

7. Cell Cycle 1) Cycle starts when a new cell forms
2) During cycle, cell increases in mass and duplicates its chromosomes
3) Cycle ends when the new cell divides`

8. Interphase 1) Usually longest part of the cycle
2) Cell increases in mass
3) Number of cytoplasmic components doubles
4) DNA is duplicated`

9. Stages of Interphase 1) G1 2) S 3) G2
a) Interval or gap after cell division
2) S
a) Time of DNA synthesis (replication)
3) G2
a) Interval or gap after DNA replication`

10. Mitosis 1) Period of nuclear division
2) Ending with telophase and cytoplasmic division
3) Four stages:
a) Prophase
b) Metaphase
c) Anaphase
d) Telophase`

11. The Spindle Apparatus 1) Consists of two distinct sets of microtubules
a) Each set extends from one of the cell poles
b) Two sets overlap at spindle equator
2) Moves chromosomes during mitosis`

12. Spindle Apparatus one spindle pole one of the condensed chromosomes
spindle equator
microtubules organized
as a spindle apparatus
one spindle pole

13. Early Prophase - Mitosis Begins
1) Duplicated chromosomes begin to condense``

14. Late Prophase 1) New microtubules are assembled
2) One centriole pair is moved toward opposite pole of spindle
3) Nuclear envelope starts to break up`

15. Prometaphase 1) Spindle forms
2) Spindle microtubules become attached to the two sister chromatids of each chromosome`

16. Metaphase 1) All chromosomes are lined up at the spindle equator
2) Chromosomes are maximally condensed`

17. Anaphase 1) Sister chromatids of each chromosome are pulled apart
2) Once separated, each chromatid is a chromosome `

18. Telophase 1) Chromosomes decondense
2) Two nuclear membranes form, one around each set of unduplicated chromosomes`

19. Results of Mitosis 1) Two daughter nuclei
2) Each with same chromosome number as parent cell
3) Chromosomes in unduplicated form`

20. TRANSITION TO METAPASE
MITOSIS
pair of centrioles
plasma
membrane
nuclear envelope
nucleus
chromosomes
TRANSITION TO METAPASE
Now microtubules penentrate the nuclear region. Collectively, they form a bipolar spindle apparatus. Many of the spindle microtubules become attatched to the two sister chromatids of each chromosome.
CELL AT INTERPHASE
EARLY PROPHASE
LATE PROPHASE
The cell duplicates its DNA, prepares for nuclear division
Mitosis begins. The DNA and its associated proteins have started to condense. The two chromosomes color-coded purple were inherited from the female parent. The other two (blue) are their counterparts., inherited from the male parent.
Chromosomes continue to condense. New microtubules become assembled. They move one of the two pairs of centrioles to the opposite end of the cell. The nuclear envelope starts to break up.

21. METAPHASE
ANAPHASE
TELOPHASE
INTERPHASE
All chromosomes have become lined up at the spindle equator. At this stage of mitosis (and of the cell cycle), they are most tightly condensed
Attachments between the
two sister chromatids of each chromosome break. The two are separate chromosomes, which microtubules move to opposite spindle pores.
There are two clusters
of chromosomes, which decondense. Patches of new membrane fuse to form a new nuclear envelope. Mitosis is completed.
Now there are two
daughter cells. Each
is diploid; its nucleus has two of each type
of chromosome, just
like the parent cell.

22. Cytoplasmic Division
1) Usually occurs between late anaphase and end of telophase
2) Two mechanisms
a) Cell plate formation (plants)
b) Cleavage (animals)`