PSYC 251 Lecture Notes - Lecture 2: Down Syndrome, Eyelid, Black Canadians
1 Feb 2015
School
Department
Course
Professor
Document Summary
Chapter 2: genetic bases of child development: there are 200-500 million sperm in the 5ml of semen ejaculate; of these, a few hundred reach the fallopian tubes. The 23 pair of sex chromosomes determines the sex of the child, with x much larger than y. The egg contributes an x, and the sperm"s contribution (x or y) determines the sex, with the y chromosome initiating a male pattern of development: each chromosome is one molecule of deoxyribonucleic acid (dna). The rungs of the helix carries the genetic code -> consists of pairs of nucleotides a-t, c-g. Chromosome 1 has the most with 3,000 genes, y the least with 200. Even then, the expression of their genes differ; only 10% provide active instructions at any time, with some genes turned on for a few hours only these are controlled by regulator genes that code for hormones.
