DNA The Molecule of Life

What is DNA? DeoxyriboNucleic Acid Chargraff A=T, G=C James Watson and Francis Crick Model of DNA Double stranded structure Bases inside

What is DNA Made of? Deoxyribose sugar Phosphate Base Purine A, G Pyrimidine T, C

What are the Structures of the bases? Purines Adenine Guanine

What are the structures of the bases? Pyrimidines Thymine Cytosine

Base pairing: how it works Hydrogen Bonding between bases: A-T Bonding 2 hydrogen bonds G-C Bonding 3 hydrogen bonds Donor and Acceptor

A View of base pairing A:T

A View of Base Pairing G:C

What is important about base pairs? Can predict sequence of one strand based on the sequence of the other. Replication and Transcription Repair of damaged DNA

Linking it all together: A, G, C or T Forms sugar Phosphate Backbone What makes DNA Different from RNA?

Replication: Why? Where? When? What? How? When cells replicate, each new cell needs it’s own copy of DNA. Where? Nucleus in Eukaryotes. Cytosol in Prokaryotes When? S phase of cell cycle What? Many proteins: major is DNA Polymerase How?

Replication How? DNA Replication Animation 5’3’ directionality Starts with RNA primer Leading Strand Lagging Strand Okasaki Fragments Sequence determined by basepairing DNA Replication Animation

Transcription DNA RNA What is the difference between DNA and RNA? Ribose Sugar Uracil not thymine

Transcription Where? What? When? Why? How? Nucleus in Eukaryotes Cytosol in Prokaryotes What? RNA Polymerase plus some minor proteins When? When RNA is needed Why? RNA’s serve many important functions in cells How?

Transcription How? RNA Synthesis Animation 5’3’ directionality Usually only one strand Uses Base-pairing Same idea as with DNA replication RNA Synthesis Animation

Translation What? Where? When? Why? How? RNA Protein Cytosol When proteins are need, after RNA is made Why? Proteins are vital for cells How?

Translation How? Translation Animation Ribosomal Subunits Codon Small subunit Large subunit Codon Triplet code used tRNA, rRNA, mRNA Translation Animation

The Genetic Code

Why is this important? Genetic Engineering Mutations Cloning Gene Splicing Mutations Cloning