Materials: Worksheet Turn in Action Plan and Progress Reports to the BLUE TRAY. Catalyst: What is the purpose of mitosis? How many daughter cells are produced in Mitosis? What happens to the chromosome number when a cell goes through Mitosis?

Announcements Work on Mutant Makers project DUE Wednesday for periods 1, 2, 4, 6. Due in 2 weeks for periods 5, 7 New tutorial days: Monday and Wednesday TUTORIAL TODAY! 3:50-4:30 Bring back progress report signed for EC. AUCTION TODAY!

Objectives I can explain the difference between sexual and asexual reproduction. I can name and identify the steps of Meiosis. I can explain the process of crossing over why it is viewed as being beneficial. I can compare and contrast the processes of Mitosis and Meiosis.

Mitosis Review

Metaphase! Mitosis: Which stage? Which stage is this? How do you know? What are the chromosomes doing? Has the DNA been duplicated at this stage? Metaphase!

Telophase! Mitosis: Which stage? Which stage is this? How do you know? What are the chromosomes doing? Has the DNA been duplicated at this stage? Telophase!

Anaphase! Mitosis: Which stage? Which stage is this? How do you know? What are the chromosomes doing? Has the DNA been duplicated at this stage? Anaphase!

Prophase Mitosis: Which stage? Which stage is this? How do you know? What are the chromosomes doing? Has the DNA been duplicated at this stage? Prophase

Interphase! Mitosis: Which stage? Which stage is this? How do you know? What are the chromosomes doing? Has the DNA been duplicated at this stage? Interphase!

Sexual Reproduction Sexual reproduction: reproduction with 2 parents 2 haploid gametes (egg and sperm) combine Fertilization: egg and sperm meet to form a new individual (zygote)

But how do we form gametes?

Meiosis

Meiosis Occurs in 2 phases: Meiosis I Meiosis II

Meiosis Meiosis: how gametes are formed 1 diploid cell divides into 4 haploid gametes 1 Body cell (diploid) 4 gametes (haploid)

Meiosis Meiosis has 2 cell division phases When a cell goes through meiosis the chromosome number cuts in half 1 Body cell (diploid) 4 gametes (haploid)

Meiosis Similar to mitosis in SOME ways Division of cells PMAT DIFFERENCES BETWEEN MEIOSIS AND MITOSIS: Meiosis Involves 2 cell divisions instead of 1 Meiosis Results in 4 cells with ½ the genetic information (HAPLOID cells) called GAMETES

You be the teacher! For the next 20 minutes, you and your group will be assigned one step of meiosis. You must use your resources to research this step. Necessary poster components Name of the phase Clear drawing of the cell (make it easy to see) Description of exactly what is happening. Be specific! You will present your findings to the class to complete our notes.

Meiosis 1

Meiosis 1

Meiosis I occurs after DNA has been replicated. Meiosis I divides homologous chromosomes in four phases.

Meiosis II divides sister chromatids in four phases. DNA is not replicated between meiosis I and meiosis II.

Crossing over during meiosis increases genetic diversity. Crossing over: process by which chromosome segments are exchanged between a pair of homologous chromosomes. occurs during prophase I of meiosis I Increases genetic diversity

Think What does meiosis form? How many cells does meiosis make? How many times does the cell divide in half in meiosis? What happens to the number of chromosomes in a cell as it goes through meiosis?

Meiosis/Mitosis comparison video

Think: Mitosis or Meiosis?

Asexual Reproduction

Gametes

Produces 2 cells

Variation

Sexual Reproduction

Cell divides in half

No variation

2 cell divisions

Produces 4 cells

Mitosis vs. Meiosis MITOSIS MEIOSIS Asexual Sexual Diploid Haploid 1 2 Sexual or Asexual? Diploid or haploid formed? Number of Divisions? Number of cells produced? Variation or Stability? Asexual Sexual Diploid Haploid 1 2 4 Stability Variation

Body Cells Chromosomes come in pairs (called homologous chromosomes) Body cells have 2 copies of each chromosome (46 chromosomes total) Diploid (2n): 2 copies of each chromosome Body cells are diploid (46 chromosomes)