Ch. 11.2 & 11.3 Notes DNA & DNA Replication

What do we already know about DNA? Why do we care about DNA?

DNA What does it stand for? Why is it so important for your body? What does it look like? Deoxyribonucleic acid It controls all your body functions and what you look like Double helix – spiral staircase

Nucleotide What is it? It is made up of three parts: 1. 2. 3. Picture: The building blocks of DNA (what it is made of) Phosphate Sugar - Deoxyribose Nitrogenous Base

Nitrogenous Base There are four different bases: 1. 3. 2. 4. Which bases are purines? Which bases are pyrimidines? Base Pairs: ____________ always pairs with ____________ Thymine (T) Adenine (A) Cytosine (C) Guanine (G) A & G C & T

Base Pairs

 Circle ONE nucleotide What does DNA look like? This shape is called a  Circle ONE nucleotide When DNA is straightened out it looks like: -Circle one nucleotide -Point to one backbone -Point to the base pairs What two things make up the DNA backbone? double helix sugar & phosphate

DNA Replication What happens? The Steps of DNA Replication 1. 2. 3. DNA Polymerase The copying of the DNA DNA unzips Free floating nucleotides pair up with open DNA ends Two new DNA strands made. It seals the new backbone of DNA together

What DNA Replication looks like Original DNA strand: Step 1 – The DNA ___________________. Step 2 – The bases _____________________________________. Step 3 – The back of the new DNA ________________________ unzips get a new partner (new base) binds together with DNA polymerase.

When does DNA replication happen? When is DNA replication done? Why is DNA replication so important? Right before the start of cell division (when your body needs to make new cells…for example to heal a cut) When you have 2 exact copies of the original DNA strand. Each new strand will be half new, half old DNA. All new cells have the same DNA as the original cell

Each new DNA is half original and half new

DNA Replication animation The DNA staircase DNA Replication animation More complex animation: (show if you want) http://www.stolaf.edu/people/giannini/flashanimat/molgenetics/dna-rna2.swf