PSYCH 130 Lecture Notes - Lecture 3: Prenatal Development, Genetic Code, Twin
Document Summary
Reproduction: sperm and egg (gametes) have 23 chromosomes, the zygote (fused) has 23 chromosome pairs. 23rd determine gender: develops from a single cell to a complex, multi-cellular human being through mitosis, determining gender. It is now believed that the chemical and physical environment of a (cid:373)other"s reproductive system can affect the (cid:272)hild"s ge(cid:374)der. Genetic code: dna duplicities itself through mitosis, genes are segments on a dna that act as hereditary blueprints. Egg and sperm zygote split in half. Different genetic composition: older women are more likely to have fraternal twins because they release more eggs. Life cycle: zygote fusion of gametes, embryo. Most rapid growth; groundwork for body structures and organs. Time period implantation to 8 weeks: fetus. By 12 weeks, sex can be determined. Organs and most brain cells have developed. Fetus uses senses to begin experiencing the world form the womb. Developments in the brain and lungs continue.
