Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
All Detentions due by Monday OR REFERRAL!!!! For a species to continue to exist. Cell division resulting in chromosome numbers being reduced by half This is achieved because there are two division The result: production of gametes 23 23 23 46 46 23 sex cells made in meiosis Gametes are haploid (n), which means they only have one set of chromosomes (23 in humans) The gametes made in the testes by males are called sperm The gametes made in the ovaries by females are called eggs Somatic cells are the BODY cells that are made in mitosis Somatic cells are diploid (2n), which means they have two homologous sets of chromosomes HUMAN HAVE 46 Total Chromosome # Diploid 38 20 46 200 78 What is the haploid # for humans? matching Chromosomes >>Two sets >>Homologous pairs = One from father & One from mother To increase genetic diversity through crossing over and independent assortment Homologous chromosomes contain different versions of the same genes from each parent Alleles are different variations of one gene Hair Color: Blonde, brown, brunette, auburn, red Crossing over creates genetic diversity Tetrads exchange sections of chromosomes This forms four new chromatids Chromosome pairs are randomly lined up and separated Creates: More genetic diversity! You can make trillions of sperm and never make the same one twice! Homologous chromosomes pair up Crossing over occurs In metaphase I, the tetrads are lined up in the middle In anaphase I, the homologous chromosomes separate and are pulled toward opposite poles Independent assortment creates new combinations of chromosomes/traits Separate the homologous pairs Meiosis II is very similar to mitosis Separate the sister chromtids Four daughter cells, called gametes The gametes are haploid (1n) The gametes are genetically different In fertilization haploid gametes combine to form a new diploid (2n) set of genes Mitosis and meiosis have several key differences: The chromosome number is reduced by half in meiosis, but not in mitosis 2. Mitosis produces two identical daughter cells, but meiosis produces four different cells 1. Meiosis # Daughter Cells # Chromosomes Genes Type of Cell Created # of Sets of genes (n) Mitosis Daughter Cells Chromosomes Genes Type of Cells Sets of genes Meiosis Mitosis 4 2 Meiosis Mitosis Daughter Cells 4 2 Chromosomes 23 46 Genes Type of Cells Sets of genes Meiosis Mitosis Daughter Cells 4 2 Chromosomes 23 46 Genes unique identical Type of Cells Sets of genes Meiosis Mitosis Daughter Cells 4 2 Chromosomes 23 46 Genes unique identical Type of Cells gametes Somatic cells Sets of genes Haploid (1N) Diploid (2N) Your cells will have two sets of chromosomes (a total of 8) In first meiotic division your will show crossing over and independent assortment Then turn you paper over and show a second meiotic division that demonstration a different crossing over event and a different independent assortment. Start with your cell in prophase (remember that the first division skips telophase and proceeds to