1. Genes
1.1. Code for specific trait
2. DNA
2.1. Structure
2.1.1. Double Helix
2.1.1.1. Discovered by James Watson and Francis Crick - 1953
2.1.1.2. Nucleotide = Phosphate, base and sugar
2.1.1.2.1. Base
2.2. Replication
2.2.1. Enzymes (protein) break up the DNA cell and helps form identical DNA cells
2.3. Cell Division
2.3.1. Mitosis - Somatic (body) cells
2.3.1.1. Stages:
2.3.1.1.1. Interphase: where DNA gets photocopied (starts of as mother cell)
2.3.1.1.2. Prophase: Centrioles produce spindle fibers (like spaghetti), sister chromatids (2 sets), nuclear membrane dissolves
2.3.1.1.3. Metaphase: Chromatids line up on metaphase plate (middle), spindle fibers connect to centromere, centrioles go to opposite poles (like north and south pole)
2.3.1.1.4. Anaphase: Spindle fibers pull chromatids apart and move to the ends of cells
2.3.1.1.5. Telophase: Nucleus forms (ends as daughter cells), chromosomes decondense
2.3.1.1.6. Cytokinesis: Division of cytoplasm
2.3.2. Gamete Production: Meiosis (Reproductive cells)
2.3.2.1. Meiosis I
2.3.2.1.1. Interphase I: Chromosomes duplicate
2.3.2.1.2. Prophase I: Homologous chromosomes pair and exchange segments/switch and crossover (Synapsis - pairing of homologs to form tetrads/4 pairs of chromosomes)
2.3.2.1.3. Metaphase: Tetrads line up in the middle
2.3.2.1.4. Pairs of homologous chromosomes split up (becomes sister chromatids again)
2.3.2.1.5. Telophase & Cytokinesis: Two haploid (half of the original information) cells form; chromosomes still double
2.3.2.2. Meiosis II
2.3.2.2.1. Prophase II: Spindle fibers form again
2.3.2.2.2. Metaphase II: Sister chromatids (23) line up in the middle
2.3.2.2.3. Anaphase: Sister chromatids separate = 23 chromosomes
2.3.2.2.4. Telophase II: Haploid daughter cells forming
2.3.2.2.5. Sister chromatids finally separate; four haploid daughter cells result, containing single chromosomes
2.3.3. Haploid (n): 1 set of chromosomes in gametes
2.3.4. Diploid (2n): 2 sets of chromosomes. One from each parent
3. Human Genome Project
3.1. Complete copy of the entire set of human gene instructions
3.2. 2003
4. Chromosomes
4.1. DNA coiled around proteins
4.2. Human: 46
4.3. 23 pairs
4.3.1. First 22 pairs are called autosomes
4.3.2. 23rd pair called sex-gender