ANTH 011 Lecture Notes - Lecture 27: Centromere, Nondisjunction, Nuclear Membrane

• School: College of The Sequoias
• Department: Anthropology (ANTH)
• Course: ANTH 011
• Professor: Allen

Document Summary

Dna structure ii: chromosomes and cell divison: dna in somatic cells exists in dispersed, uncoiled strands supported by proteins. Dna in this state is called chromatin- the diffuse form of dna as it exists during the interphase of the cell cycle; it condenses and coils into chromosomes during mitosis and meiosis. Chromosome- discrete structures composed of condensed dna and supporting proteins; each has a distinctive size and shape. Shape determined by position of centromere- condensed and constricted region of a chromosome. During mitosis and meiosis, location where sister chromatids attach to one another; size determined by size of dna. Each somatic cell in an individual"s body has the same # of chromosomes. 2 copies of each chromosome in each cell (1 from mother, 1 from father); also 2 copies of each gene, one at each locus (see below) Diploid number- the total number of chromosomes in each somatic cell. Haploid number- the total number of chromosomes in a sex cell.