1. Cell Division

2. II . Eukaryotic Cell Division
A. Cell division divided into two parts
1. mitosis = division of nucleus
2. cytokinesis = division of cytoplasm

3. B. Why cells do Mitosis & cytokinesis
A. produces clones (daughter cells)
B. unicellular organisms : reproduction
C. Multicellular organisms :
1. asexual reproduction (budding)
2. growth
3. replacement
4. repair

4. Cell Cycle – Pattern of stages in cell life
Interphase – time spent between cell divisions
(90% of cell cycle)
Mitosis – nuclear division
Cytokinesis – cytoplasmic division

5. Interphase : 3 sub-phases
G1 – gap 1- cell grows ( max size based on..
SA:V ratio)
cell performs its function for the body
cell may never leave G1 (ex nerve cells)
S – synthesis :DNA is synthesized
by semi-conservative replication
G2- gap 2 – cell gets ready to divide

6. Semi-conservative Replication in S phase make the X-shape

7. Vocab. Chromosome – naturally occurring segment of DNA Chromatin –
DNA in spread out form (thin)
Chromatid –
One double helix of DNA condensed

8. Sister Chromatids Identical Formed by semi-conservative replication
While joined at centromere = 1 chromosome

9. unduplicated
duplicated
One chromosome
One chromatid
One double helix
One chromosome
(one centromere)
Two chromatids
Two double helixes

12. Prophase Cell does what has to happen BEFORE it can move chromosomes
1. condense chromosome into
chromatids
2. break down nuclear membrane
3. attach microtubules (spindle fibers)

13. Metaphase Chromosomes lined up at equator C line up single file,
One sister chromatid on each side

14. Anaphase Centromere breaks apart
Sister chromatids move toward opposite poles

15. Telophase A) begins when chromatids reach poles B) reverses prophase
1) microtubules break down
2) Nuclear membrane reforms
3) Chromosomes de-condense into
chromatin

16. Cytokinesis Cell cytoplasm splits in half to make
2 identical daughter cells

17. Meiosis – special type of cell division
A. done only for sexual reproduction
B. makes non-identical cells with ½ the number of chromosomes
C. Cells it makes are called gametes (egg or sperm)
D. Before a cell can begin meiosis it has duplicated its chromosomes (they are X shape)

18. E. Before starting meiosis a cell goes through interphase: G1, S and G2…but then it leaves the cell cycle
F. the cell that leaves
the cellcycle can do
meiosis
G. gametes either
die or form a zygote
(the 1st cell of baby)

19. Meiosis I – separates homologous pairs

20. Meiosis II – separates sister chromatids

21. Vocab. Diploid cell – has 2 copies of each chromosome Haploid cell –
has 1 copy of each chromosome
Chromosome –
naturally occurring segment of DNA and associated proteins

22. Genome Genome = all of a cells DNA
All eukaryotes have set # Chromosome in their genome
Humans have 46
Two of each type…
23 different types