Upload
lekiet
View
216
Download
4
Embed Size (px)
Citation preview
1
Lehninger Principles ofBiochemistry
Chapter 8 sections 1 &2Nucleotides and Nucleic Acids
Copyright © 2004 by Worth Publishers
Lecture 1a
Nucleic acids are built up from nucleotides asbuilding blocks
Know the molecularstructure of a nucleotide
Ribose ordeoxyribose?
Know the general structural differences between pyrimidineand purine bases. Know the numbering system. The pentoseis attached at which N?
2
Know the structure of adenine. Differentiate it from guanine. Recognize the various pyrimidines. It takes one reaction toconvert C to U but 2 rxns to go from C to T
Only β-D-ribofuranose is present in RNA and DNAVariability in C2 and C3. The rest are planar.
5
Note: both DNA andRNA strands have a“polarity”. Direction is:5’ -> 3’ ends.
Note: phosphodiesterlinkage.
What’s main structuraldifference between RNAand DNA?
6
Tautomers of Uracil: Lactam is most common form Abbreviated way to write a deoxyribonucleic acid strand withsequence 5’-ACGTA-3’
The base rings absorb UV radiation. Most other biomoleculesdo not. (aromatic side chains of amino acids do). Changes inabsorbance at these λ’s can be used to monitor state of DNA.
DNA double helix (Watson-Crick; B-DNA). Note thedimensions.
9
X-ray diffraction data by Rosalind Franklin from DNAfibers suggested helical structure.
Know the dimensions and general structural properties.Implications.