Warm ups: List the four steps of mitosis – in order. Explain the end results of mitosis… are the cells different or identical to the parent cell, what types of cells go through mitosis, how many cells do you start with, how many cells do you end up with, How many cell divisions happen, and What is the type of cell you end up with? (haploid or diploid)

Itinerary: Meiosis notes Meiosis Video Meiosis animations Meiosis drawing worksheet

To differentiate between mitosis and meiosis Meiosis Notes Objectives: To differentiate between mitosis and meiosis To explain the 8 steps of Meiosis and explain what happens in each step

Meiosis – Cell division that creates sex cells. Nucleus divides 2 times Produce sex cells (sperm and egg) with exactly half of the chromosomes of the parent cell 3. Only happens to make cells for sexual reproduction (Oh my! “meiosis”)

Steps of Meiosis are broken down in two parts: Meiosis I and Meiosis II

Meiosis I: similar to steps of mitosis 1.) Prophase I – chromosomes already copied, nuclear membrane disappears 2.) Metaphase I – chromosomes line up in pairs in middle of cell 3.) Anaphase I – chromosome pairs separate 4.) Telophase I – cells pinch in

Meiosis II 1.) Prophase II – chromosomes do not copy 2.) Metaphase I – chromosomes line up in pairs (in middle) 3.) Anaphase I – chromosome pairs separate 4.) Telophase I – cells pinch apart, nuclear membrane forms You end up with 4 cells, with half the number of chromosomes!

Why is meiosis important? 1. It makes sexual reproduction possible

Cell Division Mitosis Meiosis 2 cell divisions Makes Body Cells – “my – toe – sis” Makes Sex Cells – “Oh my” myOsis) Creates 2 cells Creates 4 cells New cells = Same number of chromosomes (Diploid) New cells = Half number of chromosomes (Haploid)

Exit slip What type of cells does mitosis make? If a cell has 10 chromosomes and goes through meiosis, how many chromosomes will the new cells have? What process makes new body cells? What process makes reproductive cells? What is the study of heredity called?