Replication Makin’ copies

Discovering the structure of DNA DNA = Deoxyribose nucleic acid Made out of sugars (deoxyribose), phosphates and nitrogen bases

DNA 1. Double Stranded Helix 2. Hydrogen Bonds between Nitrogenous Base Pairs 3. Base Pairs are Adenine-Thymine and Guanine-Cytosine

Discovering the structure of DNA Rosalind Franklin’s DNA image “Chargoff’s rule” A = T & C = G

Discovering the structure of DNA Structure was discovered in 1953 by James Watson and Francis Crick

Cell division and DNA replication Cells divide Growth, Repair, Replacement Before cells divide they have to double cell structures, organelles and their genetic information

DNA replication

Replication The duplication of DNA which occurs during the S phase of Interphase. 1 Strand  2 Complementary Strands DNA Polymerase

One More Time!

DNA Structure thymine adenine cytosine guanine phosphate Hydrogen bond (H-bonds) DNA Structure thymine adenine cytosine guanine phosphate deoxyribose sugar Sugar / phosphate “strand” Nitrogenous base “rung” DNA nucleotide RNA nucleotide Deoxyribose sugar ribose sugar Nitrogenous base (guanine) Nitrogenous base (uracil) phosphate phosphate

DNA Replication Step 1: Hydrogen bonds between complimentary bases break DNA “unzips”

DNA Replication Step 2: DNA strands pull apart from each other

DNA Replication Step 3: DNA nucleotides in the cell match up with each side of the “unzipped” DNA each “unzipped’ strands forms a template for a new strand

DNA Replication Step 4: Each “old’ strand forms a template for a “new” strand two identical DNA molecules form Semiconservative Replication “new” strand, identical sequence to the original Link with labels “old” (original) strand