MBG 2040 Study Guide - Midterm Guide: Seedless Fruit, Sister Chromatids, Homologous Chromosome

• School: University of Guelph
• Department: Molecular Biology and Genetics
• Course: MBG 2040
• Professor: Krassimir Joseph Yankulov

Document Summary

Panel 2: variation in chromosome number and structure. Mitosis: cell division initiates by doubling each chromatid (46x2). Then chromatids are packaged and divided between daughter cells: before dna duplication 2n = 46, after dna duplication 4n = 92. Meiosis i: chromatids divide but stay together (bivalents) and segregate together: before dna duplication 2n = 46, after dna duplication 4n = 92. Segregation of sister chromatids: before division 2n = 46. Cytological techniques: giemsa banding, chromosome painting, cytogenetic analysis usually focuses on chromosomes in dividing cells, a karyotype shows duplicated chromosomes of a cell arranged for cytogenetic analysis. Many plants and most animal species are diploid (2n) Ants, bees and wasps have monoploid males (n: monoploid only 1 set of chromosomes. Polyploid more than 2 sets of chromosomes (i. e. 3n triploid, 4n tetraploid: rare in animal kingdom, 30-35% of flowering plants are polyploid. Many are sterile due to problems with pairing and separation of homologous chromosomes in meiosis.