BIOSCI 202 Lecture Notes - Lecture 2: Organelle, Dna Supercoil, Euchromatin
Document Summary
Most species have a characteristic number of chromosomes, haploid number (n) is the number of chromatin in a single set while diploid is the total number (2n). Most fungi and algae only have 1 set of chromosomes (n) and are haploid while most animals and plants are diploid (2n) and have homologous chromosomes. Haploid number can range from n=1 in an ant to n=728 in a fern. There is no relationship between chromosome number and organism complexity. The greater the number of chromosomes the greater the genetic variation from independent assortment in gametes. However too many chromosomes causes complicated assortment resulting in no viable gametes. Organisms can produce 2n gametes where n is haploid and 2n is diploid. The number of chromosomes is not auto related to the genome size or complexity. Genome size is th amount of dna in the nucleus. Metocentric: centromere in the centre of the chromosome, 1:1 ratio of arm length.