Question
question 23
During the first meiotic prophase, (a) when does crossing over, occur:(b) when does synapsis occur;(c) during which stage are the chromosomes least condensed; and (d) when are chiasmata first visible? 20. Describe the role of meiosis in the life cycle of a vascular plant 21. Contrast the chromatin fiber with the mitotic chromosome. How are the two structures related? 22. Describe the "folded-fiber" model of the mitotic chromosome. 23. You are given a metaphase chromosome preparation (a slide) from an unknown organism that contains 12 chromosomes. Two that are clearly smaller than the rest appear identical in length and centromere placement. Describe all that you can about these chromosomes. 24. If one follows 50 primary oocytes in an animal through their various stages of oogenesis, how many secondary oocytes would be formed? How many first polar bodies would be formed? How many oocytes would be formed? If one follows 50 primary spermatocytes in an animal through their various stages of spermatogenesis, how many secondary spermatocytes would be formed? How many spermatids would be formed? 25. The nuclear DNA content of a single sperm cell in Drosophi melanogaster is approximately 0.18 picogram. What would
Explanation / Answer
These chromosomes are homologous chromosomes because they are similar in size and length.One of them is inherited from female parent and another from male parent. .They have same sequence of genes
