2.4 2.4 Physical chemistry Physical chemistry of nucleic acidsof nucleic acids
A Variety of DNA Structures A Variety of DNA Structures A form A form
Separating the Two Strands of a DNA Double Helix Separating the Two Strands of a DNA Double Helix
Reuniting the Separated DNA Strands Reuniting the Separated DNA Strands
Hybridization of Two Different Polynucleotide Chains Hybridization of Two Different Polynucleotide Chains DNAs of Various Sizes and Shapes DNAs of Various Sizes and Shapes The Relationship between DNA Size and Genetic CaThe Relationship between DNA Size and Genetic Ca
pacity pacity
DNA Content and the C-Value ParadoxDNA Content and the C-Value Paradox
Nucleic acid can form several types of double helix
B-DNA A-DNA Z-DNA
Bp/turn 10.4 11 12
Rotation/bp +34.6º +34.7º -30.0º
Vertical rise/bp 3.38Å 2.56 Å 5.71Å
Helical diameiter 19 Å 23Å 18Å
A variety of DNA structure
Separating the two strands of
a DNA double helix
DNA denature;
DNA melting;
Tm (The temperature at which the DNA strands are half denatured.)
Hyperchromic shift
Reuniting the separated DNA strands
Annealing / renaturation
Three important factors:
Temperature : ~Tm-25°C
DNA concentration : the higher the concentration , the faster the annealing
Renaturation time: The longer the time,the more will occur.
C0t: DNA concentration and time
DNAs of Various sizes and shapes
•The sizes are expressed three ways:
molecular weight,
number of base pairs and
length. 1 helical turn = 10.5 bp = 34Å; 1bp = 660 d.
•Measure DNA sizes
electron microscope
gel electrophoresis
Three major activities of Three major activities of genegene
InformationInformation ReplicationReplication MutationMutation
3.1 Storing Information Overview of Gene Expression Protein Structure Protein Function The Relationship between Genes and Proteins Discovery of Messenger RNA Transcription Translation Ribosomes: Protein-Synthesizing Machines Transfer RNA: The Adapter Molecule Initiation of Protein Synthesis Translation Elongation Termination of Translation and mRNA Structure
3.1 Storing Information3.1 Storing Information
Overview of Gene Expression Overview of Gene Expression Protein Structure Protein Structure Protein FunctionProtein Function The Relationship between Genes and Proteins The Relationship between Genes and Proteins Discovery of Messenger RNA Discovery of Messenger RNA Transcription Transcription Translation Translation Ribosomes: Protein-Synthesizing Machines Ribosomes: Protein-Synthesizing Machines Transfer RNA: The Adapter Molecule Transfer RNA: The Adapter Molecule Initiation of Protein Synthesis Initiation of Protein Synthesis Translation Elongation Translation Elongation Termination of Translation and mRNA StructureTermination of Translation and mRNA Structure