1. Cell Division Chapter 2 Section 3

2. Cell Division
The Regular sequence of growth and division that cells undergo is known as the_______________.
The three main stages of the cell cycle are:
Interphase
Mitosis
Cytokinesis
Cell Cycle

3. The Cell Cycle

4. Interphase What three things occur during Interphase? The cell grows
The cell makes a copy of its DNA
The cells prepares to divide into two cells.

5. Replication of DNA What is replication?
The process by which the cell makes an exact copy of the DNA inside of the nucleus.
Chromatin

6. Cell Division
The second stage of the cell cycle during which the cell's nucleus divides int two new nuclei is called ______________.
Mitosis

7. Mitosis Mitosis is divided into the following four phases: Prophase
Metaphase
Anaphase
Telophase

8. Mitosis - Prophase
______________ condenses and coils – looks like rods.
Chromatin

9. Mitosis - Prophase
Each doubled rod of condensed chromatin is called a _______________ and held together by a _______________.
Each single strand of the chromosome is called a ____________.
Chromosome
Centromere
Chromatid
Chromatid
Centromere
Chromatid

10. Mitosis - Prophase nuclear envelope The __________________ beaks down
Spindle fibers from a bridge (attached to the centrioles).
Spindle fibers
Nuclear envelope
Centrioles

11. Mitosis - Metaphase
Spindle fibers
______________ line up across the center of the cell.
Each chromosome attaches to a spindle fiber at its ___________
Chromosomes
centromere
Chromosome
centriole

12. Mitosis - Anaphase _____________ split. Two __________ separate.
Spindle fibers
_____________ split.
Two __________ separate.
_____________ move to the opposite ends of the cell.
Cell stretches out.
Centromeres
Chromatids
Chromatids
Separating chromatids
centriole

13. Mitosis - Telophase
Cell membrane pinches inward
____________ unwind and lose their rod-like appearance
New ______________ forms around each region of chromosomes
Cell membrane starts to pinch inward.
Chromosomes
nuclear envelopes
New nuclear membrane forms
Chromosomes unwind

14. Cell Division – Final Stage
The final stage of the cell cycle that follows mitosis is called _____________.
_____________ are distributed between the two new cells, called daughter cells
At the end of cytokinesis, new cells enter _____________ and the cycle begins again.
cytokinesis
organelles
Interphase

15. Cytokinesis in animal vs. plant cells
In animal cells:
The _______________ squeezes together around the middle of the cell and the ___________ pinches into two new cells.
In Plant cells
A ___________ forms across the middle of the cell and develops into new cell membrane.
Then new ____________ form around the cell membrane
cell membrane
cytoplasm
cell plate
cell walls

16. Cytokinesis
Plant Cell
Animal Cell

17. Mitosis Animation http://www.cellsalive.com/mitosis.htm

18. Length of the cell cycle
Varies for different organisms.
Can range from ____hours to ____ hours.
Nerve, heart, and _______ cells never divide. They remain in interphase for as long as they live.
Cancer cells divide rapidly. 2 22
brain

19. DNA Structure DNA replication ensures that:
The replication process ensures that each new daughter cell will have a complete set of DNA which it needs to carry out all the cell’s activities.

20. The Discovery of the Structure of DNA
James Watson and Fransis Crick
Rosalind Franklin

21. DNA Structure
DNA looks like a twisted ladder and is often called a ________________.
double helix

22. DNA Structure
The sides of the ladder are made up of molecules of ______________ called ______________ that are alternating with molecules of phosphate.
sugar
deoxyribose

23. DNA Structure
Ladder rungs are made up of a pair of molecules called nitrogen bases (containing nitrogen and other elements). The four nitrogen bases are:
____________________(A)
____________________(T)
____________________(G)
____________________(C)
Adenine
Thymine
Guanine
Cytosine

24. DNA Structure
How do the nitrogen bases pair up to make the rungs of the DNA ladder?
______________ pairs only with _______________
Adenine
Thymine
Cytosine
Guanine

25. Nitrogen Base Pairing

26. DNA Replication
DNA molecule unwinds and separates between the nitrogen bases on each rung.
____________________ that are floating in the nucleus pair up with each half (A with T and G with C)
Two new DNA molecules are formed
The order of nitrogen bases in each new DNA molecule will exactly match the order in the original DNA molecule.
Nitrogen bases

27. DNA Replication

28. Cancer Cancer is a disease in which:
Cells grow and divide uncontrollably, damaging the parts of the body around them.
Cancer can occur when something damages a portion of DNA in a chromosome. This damage causes a change in DNA called _____________.
mutation

29. Cancer
Abnormal cells that develop uncontrollably may form a mass of abnormal cells which is called a _________________.
Treatment for cancer include _____________, ________________ and or ____________________
tumor
radiation
surgery
Drugs (chemotherapy)