1. Cell Division
Chapter 10

2. Why do you think cells in all plants and organisms need to divide?
To replace damaged tissue
To increase in size (the organism)
To reproduce

3. Repair Cells are constantly repairing themselves
If a cell can’t be repaired new ones are produced to fill the void

4. Growth Cells are also what create our size
As we grow our cells are constantly reproducing
If the reproduction rate is faster than normal, we grow

5. Reproduction Asexual Sexual Done by somatic or body cells
Done also by unicellular organisms
Creates identical daughter cells
Done by gametes or sex cells
Creates genetically different daughter cells

6. What does the DNA look like inside the nucleus of the cell?
When the cell is not dividing, the DNA looks like a tangled mass called CHROMATIN

7. When the cell is ready to divide, the DNA condenses into CHROMOSOMES
Sister chromatids
Centromere
TEM 36,600
Chromosome: a compacted piece of chromatin that is used for cell division
Sister Chromatids: A pair of identical Chromosomes
Centromere: The center section where the sister chromatids are connected

8. DNA supercoil

9. Chromosome distribution to daughter cells
LE 8-4
Sister chromatids
Centromere
TEM 36,600
Sister
chromatids
Chromosome
distribution to
daughter
cells
duplication

11. How do cells divide?
Cell Cycle: an orderly sequence of events where cells divide
The cell cycle consists of two major phases
Interphase (90% of the time)
Mitotic Phase/cell division (10% of the time)

12. The Cell Cycle
In humans and other mammals, cells that reproduce daily have a cell cycle that usually lasts 10 to 20 hours.

13. The Cell Cycle: series of events that cells go through from “birth” to reproduction

14. Interphase Phase where all metabolic processes and functions happen
Ex:
Cellular respiration
Protein creation
Movement
Growth
Other desired function

15. Interphase Interphase is also when the cell prepares for cell division
Ex:
Increases proteins
Duplicates organelles
Grows in size
Replication (duplication) of DNA

16. Mitotic Phase The division phase of the cell
There are two main parts of M phase
Mitosis
Cytokinesis

17. Mitotic phase Mitosis Cytokinesis
The division of a cells nucleus and DNA into two equal parts
Creates two daughter nuclei
Cytokinesis
The division of the cells cytoplasm
Together they create two identical daughter cells

18. Mitosis Prophase: Metaphase: Sister chromatids are formed
Formation of spindle
Nuclear envelope breaks down
Metaphase:
Sister chromatids line up
Spindle is formed and attaching to chromosomes

19. LE 8-6a LM 250  INTERPHASE PROPHASE PROMETAPHASE Early mitotic
spindle
Fragments
of nuclear
envelope
Centrosomes
(with centriole pairs)
Centrosome
Chromatin
Kinetochore
Nucleolus
Nuclear
envelope
Plasma
membrane
Chromosome, consisting
of two sister chromatids
Centromere
Spindle
microtubules

20. Mitosis Anaphase: Telophase: Cytokinesis:
Separation of sister chromatids
Spindle pulls chromosomes to either side of the cell
Telophase:
Spindle breaks down
Nuclear envelopes form (2)
Chromosomes loosen to become chromatin
Cytokinesis:
After mitosis, cell pulls apart to create two identical cells

21. LE 8-6b Metaphase plate Cleavage furrow Nucleolus forming Nuclear
ANAPHASE
TELOPHASE AND CYTOKINESIS
Metaphase
plate
Cleavage
furrow
Nucleolus
forming
Nuclear
envelope
forming
Daughter
chromosomes
Spindle

22. Cytokinesis in animal cells
Cleavage furrow
Cleavage
furrow
Daughter cells
Contracting ring of
microfilaments
SEM 140
Animal
Plants
Formation begins with indentation
Cell is pulled/ pinched until it breaks apart
Formation begins with a disc containing cell wall materials
A cell plate forms between the two nuclei

23. Cytokinesis in plant cells
Formation begins with a disc containing cell wall materials
A cell plate forms between the two nuclei
Cell wall
New cell wall
Daughter cells
Cell plate
Vesicles containing
cell wall material

25. Benign vs. malignant tumor
Benign tumor:
abnormal mass of normal cells
Malignant tumor:
Masses of cells that result from the reproduction of cancer cells
Cancer
Disease caused by cells that loose their ability to control rate of division

28. Cell Differentiation