Each person will find mitosis in the book and model each stage on a paper plate with yarn. meiosis is involved with organisms that undergo SEXUAL REPRODUCTION -means of reducing number of chromosomes in sperm or egg so when combined through fertilization, the original number is restored - reduction of genetic state from diploidy to haploidy necessary -occurs in reproductive organs in humans - ovary & testis - produces haploid cells called gametes (sperm, egg) -completed with fertilization of male gamete & female gamete to produce diploid zygoteĩ Paper Plate Models Each group will be in charge of making a paper plate model of mitosis. Mitosis: Growth, development & repair Asexual reproduction (yields identical cells) Occurs in somatic (body) cells Produces 2 identical cells Meiosis: Sexual reproduction (yields different cells) Occurs in reproductive cells (gametes) Produces 4 DIFFERENT cells So far, I’ve been talking about mitosis only What? Somatic (body) cells Why? Growth & development, repair lost or injured cells Allows many organisms to reproduce asexually But there is a 2nd type of cell division - meiosis that occurs only in select cells within certain tissue at particular phases of an organism’s lifetime.
Chromosomes replicate Cell membrane pushes inward Cell divides in two, each with a chromosome Through cell division the numbers are increased Cell then specialise and change into their various roles (blood cell, bone cell, nerve cell, etc)Ĥ Why do cells divide? Growth Reproduction Replacement of dying cells – skin, blood cellsĬell division in prokaryotes: Binary fission Bacteria have a single chromosome (versus the 46 humans have). 2 Cell Review Cells have DNA, the information needed for life.ĭNA is packaged into something called chromosomes.ģ Cell division All complex organisms originated from a single fertilized egg.
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