1. 10.2 The Process of Cell Division

2. Preparing for division..
One cell will divide into two new, identical cells
Parent cell – original
Daughter cell – new cells

3. Before division, DNA must be copied
each new cell gets an identical copy of the parent cell’s DNA

4. Chromosomes. Condensed packages of chromatin (DNA and proteins)
Prokaryotes – Contain a single circular chromosome

6. Eukaryotes usually contain several chromosomes!
Fruit fly – 8
Carrot – 18
Human – 46
Chicken – 78

7. Formation of chromosomes
DNA wraps around proteins called histones, and forms structure called nucleosomes

8. Nucleosomes condense and twist to form coils.

9. Coils twist and tighten further to form super coils.

10. Supercoils fold up to form a single chromosome.

12. Chromosomes formed during cell division contain two identical pieces
Each piece is called a sister chromatid
Held together at center by the centromere

13. Cell cycle and division of Prokaryotes..
Cycle involves periods of growth, DNA replication, and division
Divides (asexually reproduces) by process call Binary Fission
DNA is copied  Cell pinches at center
 Cell splits in half

16. Cell Cycle & Division in Eukaryotes..
Overview:
Involves two primary phases
Interphase
Interphase is separated into 3 stages
 G1 – Gap 1  S - Synthesis  G2 – Gap 2

17. 2. M Phase
M Phase is separated into 2 stages:
 Mitosis  Cytokinesis

18. Interphase Most of cell’s life is spent in interphase
Period between division in which cell performs normal functions and prepares to divide

20. G1 - Cell growth  Cell grows to normal size  Produce new proteins and organelles
S – Synthesis of DNA  DNA (chromosomes) is copied to make two identical sets of DNA
G2- Prep for mitosis
 Structures needed for mitosis are produced

21. M Phase
Very short
Mitosis – Division of the nucleus  Nucleus is broken down  Chromosomes are separated (1 set for each cell)

22. Cytokinesis – Division of the Cytoplasm
 Organelles are divided

24. Mitosis
Prophase
Metaphase
Anaphase
Telophase
PMAT

26. Prophase DNA condenses into chromosomes Nucleus begins to break down
Centrioles begin to separate and begin producing spindles
Spindles – microtubules that separate the chromosomes during mitosis

28. Metaphase Spindles attach to chromosomes
Chromosomes are pulled towards center of cell
Line up at metaphase plate

30. Anaphase Spindle fibers pull sister chromatids apart
Each sister chromatid from each chromosome moves to opposite end of the cell
Cell begins to elongate

32. Telophase
Chromatids (single chromosomes at this point) reach ends of cell
Spindle fibers break apart
Nucleus begins to reform

34. CYTOKENISIS Cell membrane pinches inward at center
Each side of cell separates
when membrane meets at center
Cell cycle will continue for each new cell at G1

37. Quiz TIME!!!!