Genetic Info DNA is the “language” the cell uses to encode genetic information In division, DNA is coiled around histones, then further coiled to form a chromosome Humans have 23 pairs of chromosomes, so 46 total chromosomes Homologous chromosomes: chromosomes that make up a pair, they contain similar genetic information Sister chromatids: separate halves of a chromosome that contain the exact same genetic information as the other half Centromere: center of a chromosome, joining point of sister chromatids

Karyotype

Cell Division of Eukaryotes Mitosis: process of cell division that creates identical somatic (body) cells – Used for growth, repair, and replacement Meiosis: process of cell division that creates similar gametic cells (sperm, eggs, spores, etc.) Both go through the cell cycle, series of steps from one division to next For mitosis, the steps are the following: (I|PMAT) – Interphase – Prophase – Metaphase – Anaphase – Telophase Prokaryotes (bacteria and other) divide by binary fission

Mitosis: Interphase Interphase: stage of growth and DNA replication G1, S, and G2

Mitosis: Prophase Prophase: formation and aPpearance of chromosomes Nuclear membrane dissolves Microtubules (originating from centrosomes) start attaching to chromosomes, the 2 centrosomes start moving to opposite ends of the cell

Mitosis: Metaphase Metaphase: stage of chromosome alignment in the Middle Chromosomes line up in the middle of the cell - sister chromatids are on either side of the cell Spindle fibers attach to the centromere of each chromosome

Mitosis: Anaphase Anaphase: stage of chromosome pulling Apart Centrosomes “reel in” chromosomes via the spindle fibers Sister chromatids are separated from each other

Mitosis: Telophase Telophase: stage of chromosome separation, Two cells Centrioles finish reeling in chromosomes to opposite side Nuclear membrane begins to re-form on either end of the cell Cytokinesis: cell membrane pinches together to make two daughter cells

Mitosis video