1. Mitosis, Meiosis, DNA, Cell cycle

2. Replication Proceeds from 5’ to 3’ Occurs in the nucleus
Occurs during interphase
Is semiconservative
Requires enzymes

3. Enzymes DNA polymerase: attaches new nucleotides
DNA Iigase: joins 3’ end of one Okazaki fragment to the 5’ end of another Okazaki fragment.
Helicase: Breaks hydrogen bonds, opens the zipper
Topoisomerase: facilitates unwinding and unzipping of DNA

4. Haploid and diploid Haploid (n): after meiosis
1 chromosome from each pair
Diploid (2n): somatic cell, zygote
2 chromosomes from each pair
Beginning of meiosis
4 chromosomes from each pair
2 x diploid number

5. Cell cycle Interphase: most time Prophase: chromosomes condense
Metaphase: replicated chromosomes line up on the equatorial plate
Anaphase: pairs separate to opposite poles
Telophase: New nuclei form
Cytokinesis: cell divides

6. Cancer Tumor, Benign, Malignant, Metastatic High rate of mitosis
Shorter cell cycle
Poor or “broken” cell regulation

7. Enzymes

8. DNA

9. Electrophoresis
Electric current pulls DNA toward the positive lead. What about DNA causes it to move to the positive end?

10. Avery, MacCleod, and McCarty

11. Avery, MacCleod, and McCarty
Heat treating and protein degrading enzyme break down protein
DNAase breaks down DNA

12. Crossing over Produces recombinations % recombination = map distance
Increases genetic variability in gametes

13. Nondisjunction Tetrads fail to separate during anaphase II
Can produce trisomy or monosomy

14. DNA Chargaff Watson Crick Adenine = Thymine Cytosine = Guanine
Adenine is complimentary to Thymine
Cytosine is complimentary to Guanine

15. Possibilities
Number of gamete possibilities = 2n, where n = number of homologous chromosome pairs
For humans 8,388,608 possible combinations

16. Mitosis and meiosis Mitosis produces copy (2n)
Growth and repair
Meiosis produces half a copy (n)
Gametes
Sperm
Egg and polar bodies