01:830:101 Chapter 7: Notes & Summary

• School: Rutgers University
• Department: Psychology
• Course: 01:830:101
• Professor: Dickson

Document Summary

Each human nucleus has 23 pairs of chromosomes. Genes are sections along each chromosome that control the chemical reactions that direct development. Dominant means a single copy of the gene is sufficient to produce its effect. Recessive means its effect appear only if the dominant gene is absent. X chromosomes, females have two per cell. Y chromosomes, males have one per cell and females have none. Sex-linked genes are genes located on the x or y chromosome. Sex-limited gene occurs equally in both sexes but exerts its effects mainly or entirely in one or the other epigenetics deals with changes in gene expression without modification of the dna sequence. Histones are proteins that wrap the dna of a chromosome into little balls. Acetyl groups are chemicals that attach to a histone and loosen the ball, increasing the expression of genes in that ball. Methyl groups are chemicals that attach to a gene and inactive it.