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?. DNA!. What is this DNA you speak of?. DNA stands for deoxyribonucleic acid - Found in nucleus of eukaryotic cells - Found in cytoplasm of protists. Why should I care about DNA?. Two main functions 1.) Stores the genetic information of an organism. Why should I care about DNA?.
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What is this DNA you speak of? • DNA stands for deoxyribonucleic acid - Found in nucleus of eukaryotic cells - Found in cytoplasm of protists
Why should I care about DNA? • Two main functions 1.) Stores the genetic information of an organism.
Why should I care about DNA? • Two main functions 2.) Contains instructions for how to construct important biological molecules. Example: Building new cells
What is the structure of DNA? • Twisted ladder-like shape called a double helix Three main components 1.) Phosphate group 2.) 5 carbon sugar 3.) Nitrogenous base
What is the structure of DNA? Three main components 1.) Phosphate group 2.) Five carbon sugar 3.) Nitrogenous base – Four types - Adenine - Guanine - Cytosine - Thymine DNA ‘backbone’ “Purines” “Pyrimidines”
Nitrogenous Bases 1.) Purines - Adenine - Guanine 2.) Pyrimidines - Cytosine - Thymine The sequence of the nitrogenous bases in DNA determines the genetic code!
Nitrogenous Bases • Base Pairing - Purines ALWAYS bond with pyrimidines! Chargaff’s Rules: - Adenine ALWAYS bonds with thymine A---T - Cytosine ALWAYS bonds with guanine C---G The amount of A = amount of T The amount of C = amount of G
What is the structure of DNA? • A single strand of DNA has a 5’ and 3’ end. 3’ end: Terminates with an exposed –OH group on deoxyribose sugar 5’ end: Terminates with an exposed phosphate group
What is the structure of DNA? • Antiparallel strands - Single strands of DNA run opposite to one another in the double-helix.
What is the structure of DNA? • Antiparallel strands - Sequence of nucleotides is typically written in the 5’ to 3’ direction. 5’-ACTG-3’ Which is NOT the same as: 5’-GTCA-3’
