PSY 2105 Lecture Notes - Lecture 2: Twin, Genotype, Down Syndrome
23 Sep 2016
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Document Summary
Chapter 3 - genetics: the biological context of. Each human cell contains 23 chromosome pairs (46 total chromosomes per cell) Sex chromosomes comprise the 23rd pair (male xy, female xx) Body cells: form the structures of the body. Forming two identical cells, each equipped with 23 pairs of chromosomes. Forming four cells with each cell containing only 23 chromosomes. These cells are the gametes (ova or sperm) During conception, a sperm merges with an ovum to form a new cell containing 23 pairs of chromosomes. Mitosis: refers to a process by which 2 identical cells are produced. Meiosis: refers to a process in which 4 cells are produced, with each containing only 23 chromosomes. Crossing over: during meiosis, the x-shaped chromosomes line up and intermix, yielding a novel genetic product. Dna: the basic genetic material, formed from pairs of base nucleotides. The bases form pairs such as adenosine-thymine or guanine-cytosine.
