The Hereditary Material - MT3 - Part 2 Flashcards
What book did Erwin Schrodinger write?
What is life?
What was Schrodinger the founder of?
Wave mechanics
What might the study of living matter reveal?
Previously unknown laws about physics
What must genes be made up?
Of a max of a few 100 to a few 1,000 atoms
Why must genes have a specific make up?
To account for genetic stability
What happens if you have more than 1000 atoms in a gene?
You could allow for too-frequent gene destruction by the thermal disruption of covalent bonds
What must genes be?
Aperiodic crystals
- every atom or group of atoms has a particular place and role in the gene
What did the model “sugar coated microbe”, streptococcus pneumoniae show?
That genes are made up of DNA
What 2 strains are there in streptococcus pneumoniae?
- S (smooth) strain
2. R (rough) strain
S strain (2)
- Causes pneumonia in mice
- It is surrounded by a slimy polysaccharide coat that renders it invisible to the mouses immune system
- acts as an invisibility cloak on the mouse
R strain (2)
- Harmless to the mouse
2. Not surrounded by a slimy polysaccharide coat, so it is visible to the mouses immune system, which deals with it
What did Fred Griffith discover?
The transformation of the nonvirulent R strain of streptococcus pneumoniae to the virulent S strain
What did Oswald Avery, Maclyn McCarthy and Colin MacLeod suggest about what molecule carried the hereditary information between cells?
Perhaps a heritable factor (a gene) is transferred from the remains of the dead S cells to the living R cells, enabling the R cells to make a protective polysaccharide coat
- thus the R cells become S cells, hereditary
- only the enzyme that extracted from the DNA actually stopped the transformation (from R-S)
What did Alfred Hershey, Martha Chase and T2’s experiment explain?
The heritability factors are transformed and carry genetic information
What do phages do to replicate?
They inject their genes into a host bacterial cell, which expresses the genes and makes more phage particles
- can radioactively label them so we can observe it
When phages inject their genes into the host cell, what are they injecting?
DNA
- not proteins
What is sulphur in?
Proteins
- not DNA
What was Watsons big question?
What was the shape of DNA
What was Pauling the first to present?
The alpha helix of the phosphorous backbone
What was Chargaffs rule?
- A pairs with T and G pairs with C
- These bases were present in equal amounts
- but the amounts of A/T different from the amount of G/C
What are hooked strands of nucleotides called?
Polynucleotides
What dod Maurice Wilkins and Rosalind Frankiln make?
X-ray diffraction pictures of crystallize DNA
The central dogma
A theory in genetics and molecular biology subject to several expectations that genetic information is coded in self-replicating DNA and undergoes unidirectional transfer to mRNA in transcription which act as templates for protein synthesis in translation
What kind of connotation did dogma have?
A negative one as it was used with the religious and political views and acceptance of authority
What did Watson and Crick first propose for the shape of DNA?
That it was a triple helix
- 3 polynucleotide strands
- bases were pointing out
- phosphorous groups were pointing in
What Watson and Crick discovered they were wrong about the triple helix, what did they propose for the shape?
That DNA is a double helix
- like with like pairing
- eg) A-A, T-T, G-G, C-C
What did the double helix with A-T and G-C pairings explain?
Chargaffs rule
What does Crick point out?
That the 2 strands must run in opposite direction
- antiparallel
