Flashcards in Molecular basis of inheritance Deck (74)
what gave the most conclusive evidence about DNA being the genetic material?
The Hershey and Chase experiment in bacteriophages
What is the Griffith's experiment?
This is an experiment in which Griffith proves that DNA is the genetic material and not the proteins. S straina and R strain.
What is transformation?
The phenomenon by which DNA when isolated from cell is introduced into the other , it bestows some of its properties to the other cell.
What is the Avery,McCleod and McCarry's experiment?
In this experiment three scientists performed these experiments in-vitro and after transferring the genetic material of the S cell to the R cell, he realised that the R cell transformed into the S cell. He treated the extract with DNAase which prevented the transfer of species , he also treated it with proteases and found that nothing happened.
What was the Hersheys and Chase exp. ?
It was the exp. that dealt with the T2 Bacteriophage.
Why was the T2 Bacteriophage used?
It was used because it contained only two things, a protein head and genetic material inside.
What were the two virus strains created for the experiment.
Since sulphur was not found in DNA, proteins were labelled with radioactive sulphur and DNA with radioactive phosphorus.
What properties must a molecule have in order to act as genetic material?
*Chemically and structurally stable
*expression in the form of mendelian characters
*It should be able to mutate
Which molecules are the foundation of life?
What are nucleic acids?
They are large polymeric molecules composed of repeating units called nucleotides
What is a nucleotide composed of ?
Where does DNA occur?
Where does RNA occur?
What is Chargaff's rule?
This rule states that the ratio of purines to pyrimidines is one. i.e. , the no. of A is equal to the no. of T etc.
What did Franklin and Wilson notice about the structure of DNA?
*The distance between successive nucleotides 3.4Å
*This helix makes one complete turn every 34Å
*There are ten nucleotides per turn
What did Watson and Crick propose?
They proposed the double helix model of DNA
What should you mention describing the structure of DNA?
* Its dimensions given by Wilkin and Franklin
*Double stranded(fulfilling density requirements)
* Sugar-Phosphate alternate backbone
What are the different types of RNA?
In which ways do these types of RNA vary ?
In size and function.
Which is the largest RNA?
Where is mRNA produced?
Just a note:
mRNA is specific for each protein
Which is the most abundant RNA?
Which is the stable form of RNA?
Which RNA has the highest molecular weight?
What helps in the binding of the mRNA and tRNA?
The rRNA molecule helps in the of mRNA and tRNA to the ribosome. This bond occurs using a Mg2+ linkage btw the phosphate molecules of the two RNAs.
Which RNA is the most heterogenous is size and stability?
Where does mRNA occur?
It occurs in the nucleolar region and the cytoplasm
IMP things about an mRNA molecule.
*Its size varies depending on the protein it codes for
*It carries coded message from a DNA molecule to a Ribosome and instructs the amino acids to sequence in protein synthesis
*mRNA is short lived
*Hence it does not accumulate in cells