PS102 Chapter Notes - Chapter 4: Environmental Modification Convention, Freckle, Heredity
Document Summary
Prenatal period encompasses the nine months or so from conception to birth. Biological parents contribute half genetic material required to create new person each. At moment of conception baby"s genes and sex are set. Each composed of specific sequence of deoxyribonucleic acid (dna) molecules. Dna and genes are arranged in strands called chromosomes found in each cell of our bodies. In most cases each sperm and each egg have 23 chromosomes. When sperm fertilizes egg, single-celled organism usually with 46 chromosomes, is created. Majority of conceptions containing errors in number of chromosomes end in miscarriage. However 1/150 children are born with too many or too few chromosomes. Genetic inheritance contained in 23 pairs of chromosomes. Each parent contributes one chromosome to each pair. Physical and psychological characteristics on display in each individual. Difficult to determine person"s genotype solely based on phenotype. Alleles: variations of same gene (such as freckle gene)
