DNA Replication & Structure Sara Safiullah

What is DNA? Controls your traits

Structure? DNA is made up of nucleotides/bases. A nucleotide is one ribose sugar and a phosphate. Adenine, Thymine, Cytosine, Guanine 2 strands winded together forming the double helix

Why do we have to replicate DNA? Mitosis (cell divison) New cells Copy information DNA replication occurs in the nucleus of cells

First step Proteins bind to the replication origin DNA strand unwinds double helix leaving 2 single strands Unzips

Step 2 Primer- short strands of nucleotides are synthesized by a polymerase enzymes called primase. DNA Polymerase is sort of like an overseer Reads DNA strand Lays down correct nitrogenous bases DNA polymerase can only add nucleotides to the 3’ hydroxyl group

Okazaki fragments Okazaki fragments are short, newly synthesized DNA fragments that are formed on the lagging template strand during DNA replication. They are complementary to the lagging template strand, together they form short double-stranded DNA sections. 

Step 3 zip strand back up Helicase rewinds DNA helix This process is referred to as semi conservative replication