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Practice! telophasemetaphaseprophaseanaphase You already know most of meiosis! Ta-da!

So, what makes meiosis different from mitosis? Like some people do with books, let’s look at the end first… What’s the final product of mitosis? What’s the final product of meiosis? 2 genetically identical cells 4 genetically different daughter cells Mitosis The first major differences between mitosis and meiosis is the products! Mitosis = 2 genetically identical cells (2n) Meiosis = 4 genetically different cells (n) Uh, Mrs. Lawrence: What’s with those ns?

‘n’ refers to the number of chromosomes we have! 23 or n + = 46 or 2n Let’s watch a movie!

So, the take home message on human chromosomes is: 23 or n + = 46 or 2n haploid (gamete) haploid (gametes) Think: Half! diploid (zygote) Two halves make a whole and wholes have 2 sets of chromosomes! For every chromosome from ma, there’s a similar one from pa. These are called homologous pairs !

Let’s look closely at a chromosome! This part, where the chromosomes sort of mix up is called crossing over! It happens during prophase I.

Ok, what’s another major difference between meiosis and mitosis? Another major difference is that in meiosis, the cells go through the phases twice!

You’ve seen this before… Meiosis I Meiosis II As you describe the phases, watch for the phases that are very different from what happens in mitosis. Don’t draw the ovals!

To Do: 1. Fill in the circle using pages 276 and 277 of your book. (Write in your own words – do not copy; you won’t learn anything that way!) 2. Shade the phases that are different from mitosis. (not just all of meiosis II, some of that is pretty much the same, too!) 3. Finish vocabulary on the back of the meiosis sheet IN YOUR OWN WORDS! 4. Complete the mitosis review by Friday!