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Meiosis Gamete Formation.

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Presentation on theme: "Meiosis Gamete Formation."— Presentation transcript:

1 Meiosis Gamete Formation

2 Homework Complete Graphing handout And 11-4 in Guided Reading Workbook

3 Reproduction Asexual reproduction - Asexual reproduction is the formation of new individuals from the cell(s) of a single parent. The new cell (daughter cell) is usually identical to the parent. Sexual reproduction - In sexual reproduction, two individuals produce offspring that have genetic characteristics from both parents. Sexual reproduction introduces new gene combinations in a population

4 Diploid - term used to refer to a cell that contains both sets of homologous chromosomes
Haploid - term used to refer to a cell that contains only a single set of chromosomes and therefore only a single set of genes

5 Chromosomes Human’s have 46 chromosomes
23 from your mother’s egg 23 from your father’s sperm A normal human cell is a diploid cell (2N) A sex cell or gamete (egg or sperm) is a haploid cell (N) In human cell’s what does N represent? 23

6 Apply what we learned about human cells to drosophila melanogaster.
Does 2N or N represent this cell best? Is this cell haploid or diploid? What number does N represent?

7 Homologous - term used to refer to chromosomes that each have a corresponding chromosome from the opposite-sex parent Homologous chromosomes are similar in shape, position and information, but not identical to each other.

8 Meiosis Meiosis is a process of reduction division in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell. Tetrad - structure containing 4 chromatids that forms during meiosis. crossing-over - process in which homologous chromosomes exchange portions of their chromatids during meiosis

9 Formation of a tetrad while going through the process of crossing-over
This occurs during prophase I of meiosis

10 Meiosis is broken down into two halves. Meiosis I an Meiosis II

11 Meiosis II

12 Gamete Formation Meiosis produces four genetically different haploid cells.

13 Comparing Mitosis and Meiosis
Similar processes with very different and distinct outcomes Mitosis results in the production of two genetically identical diploid cells (2N), whereas meiosis produces four genetically different haploid cells (N).


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