DNA REPLICATION KEY CONCEPTS: What are the steps in DNA Replication? Why does DNA replicate itself? Vocabulary: Template DNA Polymerase Mutation

DNA Replication The process of copying a DNA molecule DNA replicates before cells divide Why is it important for DNA to replicate before cells divide?

Quick Review… DNA is made up of 2 strands of nucleotides The 2 strands are complementary A pairs with? C pairs with? The strands are held together by hydrogen bonds between each of the nitrogen bases

Quick Review… What do the orange circles represent? What do the blue pentagons represent? What do A, T, G, and C represent?

DNA Replication During replication each strand is used as a template to make two new DNA molecules What does template mean? replication mean?

Original RIGHT with new left strand DNA Replication AND Original LEFT with new right strand Original RIGHT with new left strand Original DNA

Steps in DNA Replication Double helix shape unwinds An enzyme unzips the DNA molecule Breaks the hydrogen bonds between the strands Free nucleotides in the nucleus pair up with the nucleotides on the DNA strands forming new hydrogen bonds

Steps in DNA Replication Original DNA DNA unzips Free nucleotides pair up with the original LEFT strand Free nucleotides pair up with the original RIGHT strand

Steps in DNA Replication The DNA winds back up into a double helix What are the final products of DNA replication?

DNA Replication What enzyme is used to unwind the DNA?

DNA Replication Summarize the steps of DNA replication in a flow map below:

Why Replicate? Every new cell needs its own copy of the genetic material 2 new identical cells DNA copied

Accuracy Replication is also very accurate – only one in a billion base pairs are incorrectly paired! If mutations occur, DNA molecules can self-correct so the genetic code remains the same Why is it important for DNA to replicate accurately?