1. Cellular Division: Mitosis

2. Mitosis: Division of the nucleus to:
1) Grow (SA:V)
2) Reproduce (asexual reproduction)
3) Repair damage replace worn cells
IN all of these cases mitosis is followed by
Cytokinesis
(Division of cytoplasm)

3. 1) Cell Growth Cell size limited by SA:V ratio.
As cell grows SA increases…
slower than volume
SA/V……20/20 = 1 … /8000=.05
Small SA limits how fast oxygen can get in &
How fast waste can get out
Cell must divide because smaller cells have a
Larger SA:V ratio = more SA per V

4. 2) Asexual Reproduction
A) Single celled organisms reproduce by splitting in ½
This type of mitosis is called binary fission
B) multicellular organisms do asexual reproduction by
budding

5. 3)Repair damage & Replace old cells
Heal wounds
Replace skin
Replace red blood cells

7. 4) Cell Cycle A) Interphase = between cell divisions 1) G1 = gap 1
a) cell grows
b) cell does its job in the body
2) S = synthesis
a) DNA replication
b) each chromosome goes from 1 molecule -> 2 molecules
c) become X-shaped

8. d) chromosome is not supercoiled so =
chromatin (1-4 in diagram)

9. 3) G2 = gap 2
a) get ready to divide

10. B) Prophase =
first phase
1) chromosomes condense into chromatids
2) nuclear envelope breaks down
3) nucleoli disappear
4) spindle fibers form (microtubules)

11. C) Metaphase
1) chromosomes line up single file at equator

12. D) Anaphase
1) centromere breaks
2) sister chromatids move to
opposite poles

13. E. Telophase
1) chromatids reach poles
2) spindle fibers break down
3) nuclear envelope reforms
4) chromosomes decondense into
chromatin

14. F. Cytokinesis
1) dividing up cytoplasm
2) plants form cell plate
a) grow new cell wall between nuclei
3) Animals form cleavage furrow
b) microfibers of cell cortex constrict
c) pinch cell in ½

15. 3 main parts to cell cycle
1) Interphase
2) Mitosis – nuclear division
PMAT
3) Cytokinesis – dividing cytoplasm
may not happen at all
may start during telophase of mitosis

16. New Cells formed by Mitosis
1) are identical clones
(sister chromatids have identical DNA)
2) are called daughter cells
3) are diploid
a) 2 of each type of C
b) 1 from Mom
& 1 from Dad

17. 4) notation for chromosome number is n a) n represents # different C
b) in the figure above n= 2
c) in the 2nd figure n=

18. 5) Humans n = 23
a) 22 different normal C:
autosomes
b) 1 sex chromosome pair
XX = female
Xy = male
6) 2n = diploid cell with 2 of each
7) 1n = haploid cell with
only one of each type of C