Here are the answers to the pop quiz: 1. The main goal of cell division is to replicate the cell's DNA and divide it evenly between two daughter cells. 2. The 3 phases of interphase are G1 phase, S phase, and G2 phase. 3. The 4 phases of mitosis are prophase, metaphase, anaphase, and telophase. 4. If a cell has 12 chromosomes and undergoes cell division, there will be two daughter cells at the end. 5. Each of the two daughter cells will have 12 chromosomes, the same number as the original parent cell.

1. Chapter 10: Cell Growth
and Division
Growth , Development and
Reproduction

2. 10.1: Cell Growth, Division and
Reproduction
WHY DO CELLS DIVIDE???
To reproduce.
To grow bigger.
To repair injuries.
To become more efficient.

3. A. Limits of Cell Growth
1. Volume grows faster than surface area
2. Therefore a larger cell has a more difficult time
getting stuff into (oxygen & nutrients) and out of
(wastes) the cell
3. SOLUTION: Cell Division
https://www.youtube.com/watch?v=jw0ZHLJGVTY

9. B. Rates of Cell Growth
1. Vary depending on cell type
2. E. Coli every 30 minutes
3. Some cells take much longer to divide or
“stop” dividing for a while
Prokaryotic Cell Division
Binary Fission – asexual

10. Section 10.2
Chromosomes
1. Chromosomes:
o “colored body”
o seen only when the cell divides
o contain genetic info in the form of
DNA
o are coiled chromatin
2. Composition of Chromatin
o Make up chromosomes
o Composed of DNA and protein called
histones (helps to condense the
DNA)
o DNA in a chromosome is 10,000x
longer than the chromosome itself
o Nucleosome: DNA coiled around
histones (“ball with string”)
o Nucleosomes coil into supercoils –
then into chromosomes
o Must condense in order to separate
correctly during mitosis

14. 3. Chromosome Structure
o Can only see chromosomes
during division
o Each chromosome replicates
and is paired as sister
chromatids joined at a
centromere
o Human cell = 46 chromosomes
(2n)
1. “n” number = 23 = “haploid”
2. 2n = 46 = “diploid”
3. 4n = 92 (during interphase)
4. Body cells (aka somatic cells)
= 2n = 46 MITOSIS
5. Sex cells (aka eggs & sperm)
= n = 23 MEIOSIS

15. 10.2 Cell Division: Mitosis & Cytokinesis
Define mitosis and cytokinesis.
Describe the cell cycle and the changes
that take place during interphase.
Discuss the events and significance of
mitosis.

16. The Process of Cell Division

18. 2. Mitosis - Prophase

19. 3. Mitosis – Metaphase (hint “M”=middle)
 Chromosomes attach
to the spindle fibers
 Chromosomes line up
in the middle (aka
equator)
 Spindle fibers run
from centrosomes to
centromeres of the
chromosomes

20. 4. Mitosis - Anaphase (hint “A” = away)
 Centromeres split
 Spindles retract and pull
sister chromatids apart
 Chromosomes move to
opposite poles (toward
centrioles)

21. 5. Mitosis - Telophase
 Chromosomes cluster at
poles
 Chromosomes uncoil – back
into chromatin
 Nuclear envelope reforms
around each new nuclei
 Mitosis is done
 Cell membrane begins to
pinch in the middle

22. 6. Cytokinesis
 Cell membrane moves inward and pinches in the middle forming
two identical cells
 In plant cells – a cell plate (eventually becomes the cell wall)
and cell membrane appear separating the 2 new cells
 There are now 2 identical cells – same DNA, etc.

24. Mitosis Animations
 http://media.pearsoncmg.com/bc/bc_campbell_c
oncepts_5/media/assets/interactivemedia/activit
yshared/ActivityLoader.html?c6e&12&03&8B%2
0Mitosis%20and%20Cytokinesis%20Animation
 http://media.pearsoncmg.com/bc/bc_campbell_c
oncepts_5/media/assets/videos/AnimalMitosis-
V.html
 http://www.stolaf.edu/people/giannini/flashanima
t/celldivision/crome3.swf

25.  Mitosis:
AP Text Animation
AP Bioflix - Mitosis
Bozeman - Mitosis
McGraw Hill - Simple Mitosis Summary
 http://www.youtube.com/watch?v=pOsAbTi9tHw Mitosis Song
 http://www.youtube.com/watch?v=1TAzsL8qQeU Scene from Twilight

Meiosis:
Meiosis Squaredance (Long)
AP Text Animation
AP Bioflix - Meiosis
Bozeman - Meiosis
Bozeman - Mitosis vs. Meiosis
Bozeman - Mitosis vs. Meiosis Simulation

26. 10.3 Controls on Cell Growth
1. Some cells rarely/never
divide – nervous and heart
cells
2. Some cells divide daily –
skin and digestive tract
cells
3. STOP switch: cells stop
growing when they bump
into each other
4. ON switch: cut or break
in tissue cause cells to
grow rapidly (but growth
slows as healing reaches
completion)

27. Regulating the Cell Cycle
 Cyclins – proteins that regulate the timing of the cell cycle in
eukaryotic cells by
 Regulatory Proteins
 Internal Regulators – respond to event occurring inside the
cell (proceed only when certain checkpoints have been cleared)
 External Regulators – respond to events outside the cell –
direct cells to speed up or slow down the cell cycle (embryonic
development and wound healing
 Apoptosis – Programmed Cell Death
 When not occurring when needed, many disease can result
(cancer, AIDS, Parkinson’s)

28. D. Uncontrolled Cell Growth
1. = CANCER
2. Cells have lost the
ability to control their
own rate of growth
3. Continue to divide until
nutrient supply is
exhausted (may invade
other normal cell’s
space, even if they
bump into each other,
and use up their
nutrients)

29. Cancer
 Tumor – mass of cells NOT responding to
“stop” signals
Benign – does not spread to healthy surrounding
tissue
Malignant – cancerous tumors which spread to and
destroy healthy surround tissue
Metastasis – spreading
 Causes
Genetic Defects
Can be caused by lots of different factors (smoking,
TANNING, radiation exposure, viral infections,
defective genes…)
 Treatment Options …

30. 10.4 Cell Differentiation
 Differentiation – process by which cells become
specialized and differentiate into many different
types of cells
 Stem Cells – cells that are totipotent (able to develop
into any type of cell in the body – fertilized egg and
cells produced by first few cell divisions)
 Embryonic stem cells are considered pluripotent b/c they
produce the cells in the early embryo, can develop into
many different types, but not all types of cells
 Adult stem cells are considered multipotent b/c they can
develop into many different types of differentiated cells
(bone marrow cells can make different types of blood
cells, brain cells make neurons or nerve cells)

31. Pop Quiz????
1. What is the main goal of cell division?
2. What are the 3 phases of interphase?
3. What are the 4 phases of mitosis?
4. A cell has 12 chromosomes. At the end of
cell division how many cells will there be?
5. A cell has 12 chromosomes. At the end of
cell division how many chromosomes will
there be in each cell?