EFB 285 – ZOOLOGY LAB 2: Answers to paragraphs on pages 28 and 31 PAGE 28 1. Stages of meiosis, showing division of cell with three (THIS SHOULD ACTUALLY BE TWO) pairs of chromosomes. At what stage does exchange of genetic material between homologous chromosomes occur? ANSWER: During prophase I, specifically during recombination, homologous chromosomes exchange genetic material. (see Figure 3-1 in lab manual) 2. When does doubling of DNA occur? ANSWER: Doubling of DNA occurs during premeiotic interphase, or before meiosis begins (see page Figure 3-1, graphic for prophase I) 3. What is the haploid number in the example illustrated here? ANSWER: 2 (Since this organism has 2 pairs of chromosomes to begin with we can assume this is the diploid condition (i.e. 4 chromosomes). The haploid condition is ½ the # of chromosomes in the diploid condition, in this case 2 chromosomes.) 4. At what stage are bivalents (tetrads) first evident?
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