Genetics Chapter 11 Flashcards
live R
mouse lives
dead S and live R
mice died
R cells
(Non virulent) Non-pathogenic, harmless
R cells DNase and S DNA
nothing
R cells, S DNA and protease
transformed smooth
Nucleotides parts
sugar, phosphate, nitrogen base
four criteria of genetic material
information, transmission, replication, variation
composition of genetic material
-DNA
-RNA
-proteins
live S
dead mouse
dead S
Mice lived, no bacteria found
R cells and S DNA
mix, transformed smooth
R cells RNase and S DNA
transformed smooth
nucleic acids
DNA and RNA
DNA backbone
deoxyribose sugar and phosphate
James Watson and Francis Crick
discovered the structure of DNA
Chargaff’s Rule
A=T and C=G
Griffith’s experiment
genetic material could be transferred between dead bacteria and living bacteria
-two stains, rough and smooth
bacterial transformation
Griffith concluded that something from the dead type S was transforming the type R into type S
MacLeod and McCarty
fractioned type S bacterial cells into major constituents, DNA RNA cabs and proteins
Mechanism of bacterial transformation
- DNA fragments bind to cell surface
- extracellular endonuclease cuts DNA into fragments
- single DNA strand is imported into cell by uptake system
- DNA strand aligns with homologous sequence
- DNA recombines into bacterial chromosome
- the DNA heterocomplex is repaired so that lys allele is now wild type
Hershey-Chase Experiment
confirmed that DNA is the genetic material because only radiolabeled DNA could be found in bacteriophage-infected bacteria
Bacteriophage T2
-composed of DNA and protein
-phage coat remains on outside of chromosome
-only genetic material enters the cytoplasm
DNA structure
-long chains of nucleotides
-twisted into a double helix
-joined by hydrogen bonds between the complementary bases adenine and thymine or cytosine and guanine
-interacts with proteins to form chromosomes
DNA strands
-phosphate connects two sugars
-creates 5’ to 3’