Unit 10- The Chem Nature of Gene Flashcards
genetic material characteristics
must:
- replicate faithfully
- encode the pheno
- have the capactiy to vary
Kossel
DNA contains 4 nitrogenous bases
Chargaff’s Rules
A=T and G=C
Griffith’s Experiments
demon transformation in bacteria (heat killed virulent with nonvirulent caused virulent and mouse death)
Avery, MacLeod, and McCarty Experiment
nature of transferring principle: DNA
(virulent bacteria w/ substance that destroyed either RNA, proteins, or DNA. only DNA has nonvirulent)
Hershey and Chase Experiment
DNA carries the genetic info in bacteriophages (isoptypes for protein:sulfur and DNA:phosphorus. only P isotypic virus were radioactive)
Watson and Crick
3D structure of DNa (based on Rosalind Franklin’s x-ray diffraction images)
Nucleotides
sugar, phosphate, and base
- ribose = OH
- deoxyribose= H
Purines
Adenine and Guanine
- 6 sided ring and 5 sides ring
Pyrimidines
Cytosine and Thymine/Uracil
- single 6 sided ring
secondary structure of DNA
- double helix
- backbone formed from phosphodiester bonds
- hydrogen bond and base pairing
- antiparallel and complementary strands
direction of helixes
a form: small grooves diagonal to top right
b form: long grooves diagonal to top right
z form: diagonal to top LEFT
hairpin structure
when a sequence of nucleotides on the DNA strands are inverted complements
- cont = no loop
H-DNA
3-stranded; when DNA unwinds and one strand pairs with double-stranded DNA from another part of the molec
- uaually long seq of purines or pyrimidines
- common in mammals
DNA methylation
methyl groups added to nucleotide bases
- affects 3D structure