INTRODUCTION TO DNA

By the end of this lecture you will know:The basic function of DNAThe basic structure of DNAWho discovered the structure of DNA

What is DNA

• Deoxyribonucleic acid

• Master copy of hereditary information

Function: DNA must

1. Carry information from one generation to the next.

2. Put that information to work.

3. Be easily copied.

DNA is Simple

• DNA is just a string of nucleotides

• A sugar and a nitrogenous base- just 3 parts

4 different bases4 different nucleotides

1. Adenine

2. Thymine

3. Cytosine

4. Guanine

Search for the structure• By the 1950’s everybody was looking for

structure of DNA

Watson and Crick Discover the Structure of DNA

DNA – The Double Helix Model

• DNA twisted double helix “ladder”

• Rails sugar-phosphate backbone

• “Rungs” are nitrogenous bases

4 Bases Always Pair the Same Way

• Adenine-Thymine

• Cytosine-Guanine

• REVIEW• nucleotide: one sugar,

one phosphate, one base.

• 4 bases– Adenine– Guanine – Cytosine – Thymine

Q Card Quiz

• What is………..

1. The basic function of DNA

2. The basic structure of DNA

3. Name the four nitrogenous bases

4. Match the bases correctly