Question
18. Mitosis/Meiosis Place the following mejotic events in order. r __ lining-up of tetrads at the equatorial plate b __ complete de -condensation d C. __ crossing-over d. __ DNA replication e. __ dyad formation f. __ interphase g. __ migration of chromatids h. __ migration of homologous pairs i. __ partial de-condensation j. __ separation of homologous chromatids k. __ tetrad formation
Solution
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Oscar
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Answer
Here's the correct order of meiotic events:1. **f. Interphase:** DNA replication occurs during the S phase of interphase.2. **d. DNA replication:** This prepares the cell for division by duplicating the genetic material.3. **k. Tetrad formation:** Homologous chromosomes pair up, forming tetrads (bivalents).4. **c. Crossing-over:** Genetic exchange occurs between non-sister chromatids within the tetrads.5. **a. Lining-up of tetrads at the equatorial plate:** Tetrads align along the metaphase plate.6. **h. Migration of homologous pairs:** Homologous chromosomes separate and move to opposite poles of the cell (Anaphase I).7. **e. Dyad formation:** Each chromosome now consists of two sister chromatids, forming dyads.8. **i. Partial de-condensation:** Chromosomes may slightly decondense, but not fully.9. **g. Migration of chromatids:** Sister chromatids separate and move to opposite poles (Anaphase II).10. **b. Complete de-condensation:** Chromosomes decondense fully, returning to their interphase state.It's important to note that there's no "separation of homologous chromatids" in meiosis. Homologous *chromosomes* separate in Meiosis I, and sister *chromatids* separate in Meiosis II. Therefore, item "j" is not part of the correct sequence of events.