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Summary
Structure of DNA
(sugar-phosphate backbone, base pairs, double helix)
RNA Structure
(types, how is it different from DNA?)
Transcription
(RNA polymerase, 5’ cap, splicing, 3’ poly-A tail, export)
Translation
(Genetic code, reading frame, tRNA, start/stop codon, ribosomes)
Protein Folding
(pathway, chaperones)
First and Foremost: ATP
Basic Structure of DNA
Backbone
Base Pairs
Bonding
The Double Helix
Basic Structure of DNA
The Double Helix
Basic Structure of DNA
Side and Overhead View
Basic Structure of DNA
The Backbone
Basic Structure of DNA
The Base Pairs
Transcription
RNA StructureBackbone
Base Pairs
3-D Structure
Types
RNA SynthesisInitiation
Elongation
5’ Cap
Splicing
3’ End
Major differences between RNA and DNA
1. R, not D = ribose, not deoxyribose2. Single stranded rather than double stranded3. Uracil pairs with adenosine instead of thymine
Structure of RNA
The Backbone
Structure of RNA
Single Stranded– Can form base pairs
Structure of RNA
The Base Pairs
Types of RNA
mRNA “messenger” codes for protein
rRNA “ribosomal” forms the ribosome, crucial for protein synthesis
tRNA “transfer” connects RNA with correct amino acid during translation
snRNA “small nuclear” splicing
siRNA “small interfering” technique for interfering
with native mRNAs
Messenger RNA (mRNA)
Coding strand of DNA Non-coding strand
Transcription
Elongation
Transcription
Initiation
TATA box
General Transcription Factors
RNA Polymerase
Phosphorylation
One way of controlling transcription is to change
the availability or phosphorylation state of
transcription factors
Enhancer/repressor genes are several kbp from the genes they control
DNA bends frequently, allowing action at a distance
Gene Expression
3 ways to control expression before transcription
Transcription
5’ capping of new mRNA
Why cap mRNA? Some theories….
1. Stimulates translation: capped mRNA is translated more readily than uncapped
2. Provides protection against degradation by RNases that target loose 5’ ends
3. Transport out of nucleus
Transcription
Creating the 3’ End
Poly-Adenylation
Poly-A Polymerase
Poly-A binding proteins
Ready for export
Poly-A purposes:Same as capping
Transcription
Splicing Occurs during Elongation
After Transcription
The Next Stage
Translation
The Ribosome
Transfer RNA Structure
Selection and Attachment of Correct Amino Acid
Genetic Code and Reading Frames
Elongation
Termination
Translation
The Ribosome
Translation
tRNA Structure
Translation
Selection of Correct AA for tRNA
TranslationGenetic Code: how the cell interprets triplets of bases
Some point mutations are more dangerous than others!
Translation
Start Codon
Translation
Elongation
Translation
Termination
TranslationReading Frames
Protein Structure
Overview
Chaperones
Protein structure: chains of amino acids
Protein structure: folding
Primary: amino acid sequence
Secondary: beta sheet or alpha helix(both can exist in different stretches of one protein)
Tertiary: folded upon itself
Quaternary: coassembly of several aa chains into a globular protein (optional)
Protein Folding
Chaperones
Summary
Structure of DNA
(sugar-phosphate backbone, base pairs, double helix)
RNA Structure
(types, how is it different from DNA?)
Transcription
(RNA polymerase, 5’ cap, splicing, 3’ poly-A tail, export)
Translation
(Genetic code, reading frame, tRNA, start/stop codon, ribosomes)
Protein Folding
(pathway, chaperones)
