#49 Warm UP Why do you think our cells need to be able to replicate themselves? SWBAT compare and contrast Mitosis and Meiosis by analyzing diagrams and making observations Standards: 4.1c The processes of meiosis and fertilization are key to sexual reproduction in a wide variety of organisms. The process of meiosis results in the production of eggs and sperm which each contain half of the genetic information. During fertilization, gametes unite to form a zygote, which contains the complete genetic information for the offspring. 4.1d The zygote may divide by mitosis and differentiate to form the specialized cells, tissues, and organs of multicellular organisms. Change the # on your sheet to 49

Activity – Cell Division Observations Part 1 - Diagrams Look at the two diagrams. One is mitosis, and one is meiosis. Write captions in the boxes. Part 2 – Animated Interactive Get a laptop for you and your partner and go the Cell Division Link at the school website. Answer the questions on the notes sheet. Part 3 – Comparing 1. Try to fill out the table in the notes. 25 Minutes Extension: Work on the Regents Practice HOMEWORK. Work on VOCAB

Mitosis vs. Meiosis

Animation Questions In step 3 of Meiosis, what do you see happening to the paired-up chromosomes? At the end of all of the steps, how do the daughter cells (cells at the end of the processes) compare to each other? Mitosis: Meiosis: 3. How do they compare to the parent cells?

How does meiosis lead to genetic variation? Crossing-over and recombination occur during meiosis: parts of the chromosomes overlap and exchange Every gamete produced will have a new and different genetic combination of the parent’s genes! Meiosis only happens to cells in the ovaries of females and in the testes of males

MITOSIS MEIOSIS How many cells do you end with? How much DNA compared to parent? Same or different DNA? How many divisions? Asexual or sexual? What is it used for?

Regents Practice What would most likely result if mitosis was not accompanied by cytoplasmic division? 1) two cells, each with one nucleus 2) two cells, each without a nucleus 3) one cell with two identical nuclei 4) one cell without a nucleus

REGENTS PRACTICE

REGENTS PRACTICE Reflection How does meiosis contribute to the variation present among the offspring of sexually reproducing organisms? HOMEWORK Regents Practice – Mitosis & Meiosis Study Island #2 VOCAB 5 minutes Give students a few minutes to think about the question. Check notes sheet while they are writing. Call on 2-3 students to volunteer answers. HOMEWORK Vocab Practice Sheet