Meiosis 4 Meiosis and Cell Cycle Review

Engage 4 The Meiosis Dance

Explore 4 Sockosomes - You will use a hands-on manipulative that will allow you to take a cell from the beginning of meiosis to the end. 4 Mitosis/Meiosis Manipulative

Explain: Think Back to Mitosis!!! 4 What is mitosis? 4 What were the different phases of the cell cycle? 4 What happened in G1? 4 S? 4 G2? 4 What were the phases of mitosis?

Asexual vs. Sexual Reproduction 4 Mitosis 4 Asexual: CLONES –Single parent –Passes all genes from one parent –Offspring genetically identical 4 Meiosis 4 Sexual: VARIATION –Two parents –Each parent passes half of their genes –Offspring have unique genetic combination

Meiosis, Slide 1 4 Preceded by chromosome replication, but is followed by TWO cell divisions (Meiosis I & Meiosis II) 4 4 daughter cells; 1/2 chromosome number (1N); variation

Meiosis, Slide 2 4 Meiosis I 4 Prophase I 4 Metaphase I 4 Anaphase I 4 Telophase I and Cytokinesis 4 Meiosis II 4 Prophase II 4 Metaphase II 4 Anaphase II 4 Telophase II and Cytokinesis

Prophase I 4 Chromosomes condense 4 Synapsis occurs: Homologous pairs (Tetrads) come together 4 Centriole pairs move apart 4 Nuclear envelope and nucleoli disperse 4 Chromosomes begin to move to equator

Crossing Over 4 Only Crossing Over 4 Meiosis Crossing Over

Metaphase I 4 Tetrads are aligned

Anaphase I 4 Tetrads separate and are moved towards the poles 4 Sister chromatids remain attached

Telophase I and Cytokinesis 4 Cytoplasm Division 4 Does NOT replicate chromosomes again at this point 4 Getting ready for second division

Prophase II 4 Spindle apparatus forms and chromosomes move towards the Metaphase II plate

Metaphase II 4 Chromosomes align singly 4 Sister chromatids point towards opposite poles

Anaphase II 4 Sister chromatids separate

Telophase II and Cytokinesis 4 Nuclei form at opposite poles of the cell. 4 Cytoplasm divides four haploid (N) daughter cells are produced.

SpermEggs 4 Spermatogenesis 4 Oogenesis

Meiosis vs. mitosis 4 Synapsis/tetrad/ (prophase I) 4 Homologous (metaphase I) 4 Tetrads Separate (anaphase I) 4 Meiosis I separates homologous pairs of chromosomes, NOT sister chromatids of individual chromosomes. 4 Sister Chromatids join not homologous chromosomes or tetrads (Prophase) 4 Individual chromosomes (Metaphase) 4 Sister chromatids separate not tetrads (Anaphase)

Elaborate 4 You will now complete a Flow Chart comparing Mitosis and Meiosis. 4 You will also complete a chromosome number worksheet to help solidify the haploid/diploid concept.