BIOL 102 Lecture Notes - Lecture 3: Karyotype, Centromere, Chromosome
Document Summary
Bacteria typically have one, humans have 46 (23 pairs) o eukaryotic chromosomes often come in identical pairs called homologs: karyotype o a way of organizing and identifying chromosomes o performed by flattening and staining a cell"s dna as it is preparing to divide o chromosomes are paired up according to banding patterns, before cell division can occur, each chromosome must be replicated to produce two copies of each o chromatids are joined in the middle by a centromere (conglomeration of proteins) o these paired up chromatids are called mitotic chromosomes. Dividing the cytoplasm and organelles between daughter cells: the cell cycle o when cells aren"t dividing (most of the time), and haven"t performed dna synthesis (s phase) yet, they"re in the gap 1 (g1 phase) of the cell cycle o there is a checkpoint in between the g1 and s phase that checks for external chemical signals from other cells.