1. Cell Growth and Reproduction
Interphase and Mitosis

2. Reasons for Cell Division
Cell Size is Limited
Diffusion is inefficient if cell is too large.
Growth of Organism
Repair
Cuts, Scrapes, Broken Bones

3. 2 types of cell division Mitosis-produces body, or somatic cells.
Meiosis-produces sex cells, or gametes

4. Chromosome Structure
Each chromosome consists of 2 identical parts called chromatids joined together at a centromere.

5. Section 1 Chromosomes
Chromosome Structure

6. Chromosome Numbers of Various Organisms

7. III. Two Types of Chromosome
Autosome – does not determine the gender of an organism.
Sex chromosome – determines the gender of an organism.
Male (XY)
Female (XX)

8. Chromosomes (Continued)
In sexually reproducing organisms chromosomes occur in pairs.
Homologous chromosomes- Members of a pair have the same size and shape and carry the same genetic information
Diploid-Cells that contain both members of a pair
(2n)=46
Somatic Cells– Body Cells (Skin Cells)
Haploid-cells that have only one member of a pair
(n)=23
Gamete – Sex Cells
(Sperm & Egg Cells)

9. Cell Division
Produces two “daughter” cells that are identical to the original parent cell.
Parent Cell
23 Pair = 46 Chromosomes
Daughter Cell
23 Pair = 46 Chromosomes
Daughter Cell
23 Pair = 46 Chromosomes

10. The Cell Cycle – sequence of growth and division of a cell
Interphase G1 S G2
Mitosis
Prophase
Metaphase
Anaphase
Telophase
cytokinesis
REMEMBER!!!!
(IPMAT)

11. Interphase Longest period of the cell cycle
G1-chromosomes not visible; protein synthesis; growth
S-chromosomes (double) – form sister chromatids
G2-chromosomes condense; protein synthesis; centrioles replicate; growth

12. Mitosis-nuclear division
Prophase-longest stage of mitosis
The chromatin condenses to form chromosomes.
The nuclear envelope breaks down
Centrioles migrate of opposite ends of the cell
Spindles form between centrioles

13. Metaphase Spindles attach to centromeres
Chromosomes line up on the middle or equator of the cell

14. Anaphase
The spindles pull the sister chromatids of a chromosome to opposite ends of the cell.

15. Telophase Chromosomes unwind Spindles break down Nucleolus reforms
Nucleus forms around each set of chromosomes

16. Cytokinesis Stage in which cytoplasm divides
Membrane forms between the two new nuclei
In animal cells, membrane pinches in along the equator until the two new cells are separated.
Plant cells have a rigid cell wall that prevent pinching; cell plate forms along the equator and a cell wall forms along each side of the cell plate until the two new cells are separated.

18. Mitosis guarantees genetic continuity.
New cells are identical to original cell.
Cells perform specific functions
Examples- blood cells, nerve cells, bone cells, etc
Tissues- group of cells that work together to perform the same function
Examples - blood, nervous, bone, etc.
Organs-Made up of tissues that work together to perform a specific activity
Examples - heart, brain, skin, etc.
Organ systems -multiple organs work together to perform a specific function for the organism.
Examples - circulatory system, nervous system, skeletal system, etc.
Entire living things that can carry out all basic life processes.
Examples - bacteria, amoeba, mushroom, sunflower, human

19. Control of the cell cycle
Enzymes monitor cell progress during the cell cycle
Cancer-uncontrolled cell division
Tumor-mass of cancerous cells
Metastasis-cancer cells spread
Leading cause of deaths related to cancer
Causes of cancer
Problems with the genes
Cigarette smoke
Air and water pollution
UV radiation
Viral infections

20. Pictures and examples are taken from various websites.