Flashcards in DNA and proteins - lecture 1 Deck (20)
Who discovered nuclein and cells?
Friedrich Meischer. He washed pus bandages in salt then soaked them in weak alkaline solution. There was a ppt at the bottom, the cells has lysed ad the nuclein was at the bottom
What are the two types of Streptococcus pneumonia ?
- Smooth virulent strain ( polysaccharide coat protects it from immune system)
- Rough nonvirulent ( lacks polysaccharide coat)
What is the transforming principle?
How was the transforming Principe discovered?
- Smooth virulent strain when killed by heat the mouse can still survive
- When heat killed smooth virulent strain is mixed with living rough non-virulent strain , mouse is still killed .
Who discovered the transforming principle first?
Frederick Griffith in 1928
who determined that the ' transforming principle' is DNA?
- Oswald Avery
- Colin MacCleod
Who determined the base ratios and when?
Erwin Chargaff in 1949
When did Rosalind Franklin and Maurice Wilkins produce their X-ray diffraction patterns?
When did Francis and Crick discover the structure of DNA
Structure of a nucleotide
5 carbon pentose sugar + nitrogenous base + phosphate base
Structure of a nucleoside
5 carbon pentose sugar and nitrogenous base
What are purines?And what are their names?
nucleotide with a 2 carbon nitrogenous base . Adenine and Guanine.
What are pyrimidines? And what are their names?
nucleotides with 1 carbon nitrogenous base. Cytosine , thymine and uracil
how are carbons labelled in a ring?
the carbons on the sugar are termed 3 prime or 4 prime etc ...
What are the two bonds in DNA strands?
N-glycosidic bonds and phosphodiester bonds.
What is a N- glycosidic bond made of?
Links nitrogenous base to the C1 pentose
What is the phosphodiester bond made of?
links the 5' and 3' pentose sugars
Features of DNA
- Right handed helix
- wide and deep major groove
- narrow and deep minor groove
- tiny central axis
Differences between RNA and DNA
- less pronounced grooves
- uracil instead of thymine