1. DNA Structure Macromolecule – nucleic acid
View as a spiral ladder or double helix
Composed of nucleotides - deoxyribose sugar, phosphate group, and nitrogenous bases
Nitrogenous bases – thymine, adenine, cytosine, & guanine
Base pairing
A bonds with T and C bonds with G
Double strands are held together by hydrogen bonds

2. Chromosomes Structures in the cell that contain genetic information
Passed on from one generation to the next
Made up of chromatin
Humans body cells contain 46

4. KARYOTYPE

5. Intro to Genetics
Normally all cells have 2 sets of chromosomes; one from ma and one from pa. Humans have 23 pair or 46 chromosomes.
46 is our diploid (2N) number of chromosomes.
Meiosis
Process by which gametes (sex cells) receive only one set of chromosomes.
23 is our haploid (N) number of chromosomes.
Sperm and eggs are haploid. They only have 23 chromosomes.

6. Intro to Genetics
Each chromosome we receive from a parent has a corresponding one we receive from the other parent. (ma and pa). They each contain the same genes (sections of DNA covering a particular trait).
These chromosomes are said to be homologous.

7. CELL GROWTH and DIVISION Examples
Cells must multiply to:
*replace damaged or dead cells.
*Repair wounds
*Body Growth

8. CELL GROWTH An increase in size due to the production of more cells
Growth is controlled by the amounts of food, oxygen, and water that enter the cell.
And waste products that leave the cell

9. RATES OF CELL GROWTH
Different types of cells divide at different rates
E-coli can double every 30 minutes

10. CONTROLS ON CELL GROWTH
Cells in the heart and nervous system rarely divide.
Cells in the skin and digestive system divide rapidly throughout life.
Cell growth and division can be turned on and off
When an injury occurs cell division increases near the injury.
When the healing process is complete cell division stops.

12. LIFE SPANS OF DIFFERENT HUMAN BODY CELLS
Brain Cells years
Liver Cells 200 days
Skin Cells 20 days
Stomach Cells 2 days
Muscle Cells mitosis does not occur. You are born with all the muscle cells you will have.

13. Uncontrolled Cell Growth
Cancer: A disorder in which some cells have lost the ability to control their own growth rate.

14. Cell Division Example
Mitosis: The process by which the nucleus of the cell is divided into 2 nuclei, each with the same number of chromosomes as the parent cell.
Cytokinesis: The process by which the cytoplasm divides, forming 2 distinct cells

15. The Cell Cycle
The period of time from the beginning of one mitosis to the beginning of the next
1 The cell grows
2 prepares for division
3 Divides to form 2 daughter cells

16. The Cell Cycle G1, S, and G2 represent the 3 phases of Interphase
G1=Growth
S=DNA Synthesis
G2=Growth

17. The cell Cycle M= Mitosis and Cytokinesis
The Nuclei and cell divides to form 2 new ones

18. Interphase The period between Cell Divisions G1: Cell growth
S: DNA Replication occurs in this phase
G2: The synthesis of organelles required for cell division

19. 4 Phases of Mitosis
Prophase
Metaphase
Anaphase
Telophase

20. Prophase 1st phase of mitosis The longest phase 50-60% of mitosis
Chromosomes become visible
Centrioles separate to opposite sides of the cell
Spindle develops
Nuclear envolope breaks down

21. Metaphase Shortest phase (few minutes)
Chromosomes line up along the center of the cell
Spindles connect from the centromeres to the chromosomes

22. Anaphase 3rd phase of mitosis Begins when sister chromatids split
Sister chromatids separate to oppposite ends of the cell
Anaphase ends when movement stops

23. Telophase The final phase of mitosis The nuclear envelope reforms
The spindle breaks apart
Mitosis is complete
Cell division is not

24. Cytokinesis Division of the cytoplasm into 2 cells
Animal Cells: The Cell membrane pinches inward
Plant Cells: a cell plate forms to separate the cells (It becomes the cell wall)

25. E-coli, salmonella and other bacteria can reproduce quickly
E-coli, salmonella and other bacteria can reproduce quickly. Lets say 30 minutes. If you eat contaminated food and it contains one cell how many will you have after 4 hours? 5 hours?

26. ½ 2
1hr 4
1 +1/2 8
2 16
2+1/2 32
3 64
3 + ½ 128
4 256
4 +1/2 512