Meiosis Meiosis and Cell Cycle Review
Jan 05, 2016
Meiosis
Meiosis and Cell Cycle Review
Engage
The Meiosis Dance
Explore
Sockosomes - You will use a hands-on manipulative that will allow you to take a cell from the beginning of meiosis to the end.
Mitosis/Meiosis Manipulative
Explain: Think Back to Mitosis!!!
What is mitosis? What were the different phases of the cell
cycle? What happened in G1? S? G2? What were the phases of mitosis?
Asexual vs. Sexual Reproduction
Mitosis Asexual: CLONES
– Single parent
– Passes all genes from one parent
– Offspring genetically identical
Meiosis Sexual: VARIATION
– Two parents
– Each parent passes half of their genes
– Offspring have unique genetic combination
Meiosis, Slide 1
Preceded by chromosome replication, but is followed by TWO cell divisions (Meiosis I & Meiosis II)
4 daughter cells; 1/2 chromosome number (1N); variation
Meiosis, Slide 2
Meiosis I Prophase I Metaphase I Anaphase I Telophase I and
Cytokinesis
Meiosis II Prophase II Metaphase II Anaphase II Telophase II and
Cytokinesis
Prophase I
Chromosomes condense Synapsis occurs:
Homologous pairs (Tetrads) come together
Centriole pairs move apart Nuclear envelope and
nucleoli disperse Chromosomes begin to
move to equator
Crossing Over
Only Crossing Over Meiosis Crossing Over
Metaphase I
Tetrads are aligned
Anaphase I
Tetrads separate and are moved towards the poles
Sister chromatids remain attached
Telophase I and Cytokinesis
Cytoplasm Division Does NOT replicate
chromosomes again at this point
Getting ready for second division
Prophase II
Spindle apparatus forms and chromosomes move towards the Metaphase II plate
Metaphase II
Chromosomes align singly
Sister chromatids point towards opposite poles
Anaphase II
Sister chromatids separate
Telophase II and Cytokinesis
Nuclei form at opposite poles of the cell.
Cytoplasm divides four haploid (N) daughter cells are produced.
Sperm Eggs
Spermatogenesis Oogenesis
Meiosis vs. mitosis
Synapsis/tetrad/ (prophase I)
Homologous
(metaphase I) Tetrads Separate
(anaphase I) Meiosis I separates
homologous pairs of chromosomes, NOT sister chromatids of individual chromosomes.
Sister Chromatids join not homologous chromosomes or tetrads (Prophase)
Individual chromosomes
(Metaphase) Sister chromatids separate
not tetrads (Anaphase)
Elaborate
You will now complete a Flow Chart comparing Mitosis and Meiosis.
You will also complete a chromosome number worksheet to help solidify the haploid/diploid concept.