2. Announcements
Test Corrections: 12/6 – 12/16
Take Biospheres Home

3. p. 329 A.Q. 1ab, 3a & p. 327 Analyzing Data 1, 4
Question of the Day
Question: What is mitosis and what does it create? Answer: … … …
More than 25 types of elements
3’s Turn In:
p. 329 A.Q. 1ab, 3a & p. 327 Analyzing Data 1, 4

4. Biosphere Report: Part 2
More than 25 types of elements

5. Meiosis Notes &
Vocabulary Sheet

6. Before Mitosis:
Phases of Mitosis:
Interphase
Prophase
Metaphase
Anaphase
Telophase
Interphase
Prophase
Metaphase
Anaphase
Telophase

7. Unit 5 Vocabulary
meiosis- cell divisions resulting in 4 unique cells with half of the normal number of chromosomes
19. mitosis- cell division resulting in 2 identical cells

9. Introduction
Meiosis is a type of cell division that makes cells with half the number of chromosomes
How 1N gametes (sex cells) are created

10. Unit 5 Vocabulary diploid (2n)- 2 sets of chromosomes
17. haploid (1n)- 1 set of chromosomes

11. Introduction
Meiosis creates genetic diversity through the recombination of chromosomes
DNA is replicated during interphase beforehand
In meiosis, the cell will divide twice to make four 1N cells

12. Prophase I Meiosis I DNA coils into chromosomes Spindle fibers appear
Homologous chromosomes pair together, forming a tetrad

13. Unit 5 Vocabulary
24. homologs (homologous chromosomes)- a pair of corresponding chromosomes, 1 from each parent
25. tetrad- a pair of duplicated homologous chromosomes

14. Meiosis I
Prophase I
Portions of chromatids may break off and attach to adjacent chromosomes; this is called crossing-over
Crossing-over exchanges genetic material between maternal and paternal chromosomes
20. crossing over- sections of chromatids are broken off and exchanged

15. Metaphase I Meiosis I Spindle fibers attach
Tetrads line up in middle of cell

16. Meiosis I
Anaphase I
Homologous chromosomes are pulled apart to opposite ends of the cell
Which homologous chromosome goes to which end is random

17. Telophase I Meiosis I Cytokinesis occurs, forming two 1N cells

18. Meiosis II
Prophase II
Spindle fibers appear

19. Meiosis II
Metaphase II
Chromosomes move toward middle of the cell

20. Meiosis II
Anaphase II
Chromatids separate, pulled to opposite ends of each cell

21. Telophase II Meiosis II Cytokinesis occurs again
Four 1N cells are formed

22. Formation of Gametes Sperm and eggs are produced through meiosis
makes 4 sperm in testes
makes 1 ovum (egg) and 3 polar bodies in ovaries

23. Unit 5 Vocabulary 9. ovum (ova)- a female sex cell or egg
10. sperm- a male sex cell
8. gamete- sex cells (ex: sperm or ovum)
7. somatic/body cell- a cell in an organism not used in sexual reproduction

24. Meiosis vs. Mitosis Lab

25. Mitosis Meiosis A process of cell division
DNA is replicated in prophase
Produces 2 identical cells
Produces diploid cells (2N)
Produces somatic (body) cells
A process of cell division
DNA is replicated in prophase
Produces 4 different cells
Produces haploid cells (1N)
Produces gametes (sex cells)