DNA Replication

The Basics: DNA is held inside and can not leave the nucleus. 46 chromosomes in every human body cell. (Recall there is ½ genetic information in sex cells, so there are 23 chromosomes in every sex cell.) DNA is held inside and can not leave the nucleus. Chromosomes are formed when DNA wraps around histones, which help coil up the chromatin.

WHAT? WHY? WHEN? What: DNA Replication is the process of making an identical copy of the DNA in a cell. Why: DNA needs to be copied for cell division (mitosis or meiosis) so that when the cell divides, each cell contains the correct amount of genetic information. When: During Interphase

STEPS TO DNA REPLICATION DNA is unwound and “unzipped” by the enzyme Helicase. Nucleotides are added to the free ends of the original nucleotides by the enzyme DNA Polymerase.

2 Strands b/c DNA is a Double Helix Example: DNA Original Strand: ATTAGCCGAT TAATCGGCTA AFTER DNA REPLICATION: made 2 identical copies of DNA 2 Strands b/c DNA is a Double Helix Original Strand Daughter Strand

MODEL: Semi-Conservative Model: When DNA is replicated, each strand will consist of one parent(template) strand and one daughter (complementary) strand. Semiconservative Model

DNA Replication Visual Histones & DNA Replication During Cell Division https://www.youtube.com/watch?v=5qSrmeiWsuc