Nature v nurture agree that much of potential comes form the genes inherited. Chromosomes: threadlike structures in the nuclei of cells that contain genetic material. Each sperm and egg contains 23 chromosomes, giving the new organism 23 pairs. Autosomes: first 22 pairs of chromosomes: these are matching pairs. Sex chromosomes: 23rd pair of chromosomes; these determine the sex of the child. Deoxyribonucleic acid (dna): molecule compound of four nucleotide bases that is the biochemical basis of heredity: adenine, thymine, guanine, cytosine, thymine can bond only with adenine (and vice versa, guanine can bond only with cytosine (and vice versa) Gene: group of nucleotide bases that provide a specific set of biochemical instructions. Phenotype: physical, behavioural, and psychological features that result from the interaction between one"s genes and the environment. Alleles: variations of genes: remember, genes come in pairs. Homozygous: when the alleles in a pair of chromosomes are the same.