Molecular Basis of Inheritance

Compare the structure of purines and pyrimidines. Can you find out why the distance between two polynucleotide chains in DNA remains almost constant?

In some viruses the flow of information is in reverse direction, that is, from RNA to DNA. Can you suggest a simple name to the process?

If the length of E. coli DNA is 1.36 mm, can you calculate the number of base pairs in E.coli?

Can you think of any difference between DNAs and DNase?

Can you recall the two chemical differences between DNA and RNA?

Can you recall what centrifugal force is, and think why a molecule with higher mass/density would sediment faster?

If E. coli was allowed to grow for 80 minutes then what would be the proportions of light and hybrid densities DNA molecule?

Can you now write the sequence of RNA transcribed from the above DNA?

If following is the sequence of nucleotides in mRNA, predict the sequence of amino acid coded by it (take help of the checkerboard): - AUG UUU UUC UUC UUU UUU UUC-

Now try the opposite. Following is the sequence of amino acids coded by an mRNA. Predict the nucleotide sequence in the RNA: Met-Phe-Phe-Phe-Phe-Phe

Can you now correlate which two properties of genetic code you have learnt?

Can you think for how long the lac operon would be expressed in the presence of lactose?

Group the following as nitrogenous bases and nucleosides: Adenine, Cytidine, Thymine, Guanosine, Uracil and Cytosine.

If a double stranded DNA has 20 per cent of cytosine, calculate the per cent of adenine in the DNA.

If the sequence of one strand of DNA is written as follows: 5'-ATGCATGCATGCATGCATGCATGCATGCATGCATGCATGC-3' Write down the sequence of complementary strand in 5'–3' direction.

If the sequence of the coding strand in a transcription unit is written as follows: 5'-ATGCATGCATGCATGCATGCATGC-3' Write down the sequence of mRNA.

Which property of DNA double helix led Watson and Crick to hypothesise semi-conservative mode of DNA replication? Explain.

Depending upon the chemical nature of the template (DNA or RNA) and the nature of nucleic acids synthesised from it (DNA or RNA), list the types of nucleic acid polymerases.

How did Hershey and Chase differentiate between DNA and protein in their experiment while proving that DNA is the genetic material?

List two essential roles of ribosome during translation.