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Meiosis Pre-Discussion Assignment Meiosis ● Crash Course Biology o Meiosis: CrashCourse Biology #13 ▪ https://www.youtube.com/watch?v=qCLmR9YY7o&list=PL3EED4C1D684D3ADF&index=14 1. What are the main differences between mitosis and meiosis? Mitosis ● Mitosis is the genetic separation of a parent cell, resulting in two daughter cells that are identical to the parent and to each other.

Meiosis ● Meiosis is a 2 cycle genetic separation of a parent cell, resulting in four daughter cells, and the chromosomes separate, leading to 4 daughter cells that are different to each other and different to the parent.

● The daughter cells have no change in the number chromosomes in each cell ● The daughter cells are diploid

● Chromosomes synapse with each other, resulting in the genetic info to mix between the chromosomes. ● The daughter cells have half of each chromosome ● The daughter cells are haploid

● 1 division

● 2 divisions

2. What are homologous chromosomes? Homologous chromosomes are chromosomes that share the same structural features (same size, same centromere positions) and the same genes at the same loci positions (while the genes are the same, alleles may be different). 3. What is the difference between haploid and diploid? Diploid cells contain two complete chromosomes sets. Haploid cells contain one complete chromosome set. 4. How many divisions are in meiosis? 2 divisions 5. How many cells form in meiosis? 4 daughter cells form in meiosis. 6. Where does meiosis in men occur? Women? In men, meiosis occurs in the seminiferous tubules of the testicles. In women, it

occurs in the oogonia cells. 7. What are the diploid cells that begin this process in men? Women? In men, the diploid cells that begin meiosis is sperm. In women, thye are eggs. 8. In what phase does the DNA replicate? DNA replication occurs in the S phase 9. What happens in Prophase 1? In prophase 1, homologous chromosomes form bivalents (or tetrads), and crossing over occurs between non-sister chromatids 10. Each chromosome contains how many chromatids? Each chromosome contains 2 chromatids. 11. What is crossover and recombination? Crossover is when two homologous chromosomes break and then reconnect but to the different end piece. Homologous recombination is the process by which two chromosomes, paired up during prophase 1 of meiosis, exchange some distal portion of their DNA. 12. What is the main difference between Prophase 1 in meiosis and Prophase in mitosis? In mitosis, homologous pairs do not interact with each other. In meiosis, homologous pairs cross over. 13. What does recombination create? Recombination creates new combinations of alleles 14. Relate meiosis to natural selection and evolution. Meiosis and fertilization create genetic variation by making new combinations of gene variants (alleles). In some cases, these new combinations may make an organism more or less fit (able to survive and reproduce), thus providing the raw material for natural selection. 15. Why are all four chromatids different? The chromatids are different because of recombination. 16. What chromosomes make someone a male? Female? One X and one Y chromosome makes someone male. Two X chromosomes makes someone female. 17. What splits in Metaphase 1? The homologous pairs split in metaphase 1 18. What is the result of the end of Meiosis 1? How many cells and how much genetic material?

The result of meiosis 1 is two haploid daughter cells. 19. Is there DNA replication between Meiosis 1 and Meiosis 2? There is DNA replication between meiosis 1 and meiosis 2. 20. What is the final result of Meiosis? How many cells and how much genetic material? The final result is four different haploid daughter cells, 21. How many sperm form in Meiosis? Four haploid sperm cells form in meiosis . 22. How many eggs form in Meiosis? What else forms and why? 1 egg forms in meiosis. The other three cells are polar bodies (small cells that do not develop into eggs)....