BIOL 1000 Chapter Notes - Chapter 9: Synapsis, Y Chromosome, Sister Chromatids
22 Apr 2014
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9. 1 mechanism of genetic recombination: alleles are different versions of the same gene, genetic recombination requires: Two dna molecules that differ from one another. Mechanism for bringing the dna molecules into close proximity. Plants and some fungi: an alternating-generations life cycle. Either the haploid or the diploid phases are multicellular. The diploid phase is limited to a single cell produced by fertilization which then immediately undergoes meiosis. The haploid phase is unicellular: the products of meiosis are haploid gametes, the diploid phase is restored when one gamete fuses with another at fertilization. To reduce chromosome # (from diploid to haploid) To generate diversity in sexually reproducing organisms: occurs only in eukaryotes that are at least diploid have at least 2 copies of each chromosome. Premeiotic interphase: dna replicates and the chromosomal proteins are duplicated. Producing two copies, the sister chromatids, of each chromosome.
