Biology

Molecular Basis of Inheritance

Question:

List the various markers that are used in DNA finger printing.

Answer:

Different DNA marker systems such as Restriction Fragment Length Polymorphisms (RFLPs), Random Amplified Polymorphic DNAs (RAPDs), Amplified Fragment Length Polymorphisms (AFLPs), Simple Sequence Repeats (SSRs) which also called as microsatellites, Single Nucleotide Polymorphisms (SNPs) and others have been developed.

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Molecular Basis of Inheritance

Q 1.

What is DNA polymorphism? Why is it important to study it?

Q 2.

Define transformation in Griffith's experiment. Discuss how it helps in the identification of DNA as the genetic material.

Q 3.

Now, sequencing of total genomes getting is less expensive day by the day. Soon it may be affordable for a common man to get his genome sequenced. What in your opinion could be the advantage and disadvantage of this development?

Q 4.

Would it be appropriate to use DNA probes such as VNTR in DNA finger printing of a bacteriophage?

Q 5.

List two essential roles of ribosome during translation.

Q 6.

Explain (in one or two lines) the function of the followings:
(a) Promoter (b) tRNA
(c) Exons

Q 7.

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

Q 8.

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

Q 9.

The total number of genes in humansds far less (< 25,000) than the previous estimate (upto 1,40,000 gene). Comment.

Q 10.

What is the function of histones in DNA packaging?

Q 11.

Name any three viruses which have RNA as the genetic material.

Q 12.

What is the cause of discontinuous synthesis of DNA on one of the parental strands of DNA? What happens to these short stretches of synthesised DNA?

Q 13.

Give any six features of the human genome.

Q 14.

Differentiate between the followings:
(a)Repetitive DNA and Satellite DNA
(b)mRNAand tRNA
(c)Template strand and Coding strand

Q 15.

Comment on the utility of variability in number of tandem repeats during DNA finger printing.

Q 16.

List the various markers that are used in DNA finger printing.

Q 17.

Sometimes cattle or even human beings give birth to their young ones that are having extremely different sets of organs like limbs/position of eye(s) etc. Comment.

Q 18.

A low level of expression of lac operon occurs at all the time. Can you explain the logic behind this phenomena?

Q 19.

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

Q 20.

Name a few enzymes involved in DNA replication other than DNA polymerase and ligase. Name the key functions for each of them.

Q 21.

Do you think that the alternate splicing of exons may enable a structural gene to code for several isoproteins from one and the same gene? If yes, how? If not, why so?

Q 22.

You are repeating the Hershey-Chase experiment and are provided with two isotopes: 32P and 15N (in place of 35S in the original experiment). How do you expect your results to be different?

Q 23.

What would happen if histones were to be mutated and made rich in acidic amino acids such as aspartic acid and glutamic acid in place of basic amino acids such as lysine and arginine?

Q 24.

Based on your understanding of genetic code, explain the formation of any abnormal hemoglobin molecule. What are the known consequences of such a change?

Q 25.

During in vitro synthesis of DNA, a researcher used 2′, 3′ – dideoxy cytidine triphosphate as raw nucleotide in place of 2′-deoxy cytidine. What would be the consequence?

Q 26.

Give an account of the methods used in sequencing the human genome.

Q 27.

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

Q 28.

In the medium where E. coli was growing, lactose was added, which induced the lac operon. Then, why does lac operon shut down some time after addition of lactose in the medium?

Q 29.

Briefly describe the following:
(a) Transcription (b) Polymorphism
(c) Translation (d) Bioinformatics

Q 30.

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

Q 31.

What are the functions of (i) methylated guanosine cap, (ii) poly-A "tail"in a mature on RNA?

Q 32.

During the course of evolution why DNA was chosen over RNA as genetic material? Give reasons by first discussing the desired criteria in a molecule that can act as genetic material and in the light of biochemical differences between DNA and RNA.

Q 33.

There is a paternity dispute for a child'. Which technique can solve the problem? Discuss the principle involved.

Q 34.

Who revealed biochemical nature of the transforming principle? How was it done?

Q 35.

In an experiment, DNA is treated with a compound which tends to place itself amongst the stacks of nitrogenous base pairs. As a result of this, the distance between two consecutive base increases from 0.34 nm to 0.44 nm. Calculate the length of DNA double helix (which has 2 x 109 bp) in the presence of saturating amount of this compound.

Q 36.

Why is the Human genome project called a mega project?

Q 37.

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

Q 38.

Distinguish between heterochromatin and euchromatin. Which of the two is transcriptionally active?

Q 39.

The enzyme DNA polymerase in E.coli is a DNA dependent polymerase and also has the ability to proofread the DNA strand being synthesised. Explain. Discuss the dual polymerase.

Q 40.

During DNA replication, why is it that the entire molecule does not open in one go? Explain replication fork. What are the two functions that the monomers (dNTPs) play?

Q 41.

How has the sequencing of human genome opened new windows for treatment of various genetic disorders. Discuss amongst your classmates.

Q 42.

There is only one possible Sequence of amino acids when deduced from a given nucleotides. But multiple nucleotides sequence can be deduced from a single amino acid sequence. Explain this phenomena.

Q 43.

Give an account of Hershey and Chase experiment. What did it conclusively prove? If both DNA and proteins contained phosphorus and sulphur do you think the result would have been the same?

Q 44.

Given below is the sequence of coding strand of DNA in a transcription unit. 3’AATGCAGCTATTAGG’  Write the sequence of
(a) its complementary strand
(b) the mRNA

Q 45.

In a nucleus, the number of ribonucleoside triphosphates is 10 times the number of deoxy ribonucleoside triphosphates, but only deoxy ribonucleotides are added during the DNA replication. Suggest a mechanism.

Q 46.

What is DNA fingerprinting? Mention its application.

Q 47.

Define a cistron. Giving examples differentiate between monocistronic and polycistronic transcription unit.

Q 48.

A single base mutation in a gene may not ‘always' result in loss or gain of function. Do you think the statement is correct? Defend your answer.

Q 49.

Give an account of post transcriptional modifications of an eukaryotic mRNA. “

Q 50.

If the sequence of one strand of DNA is written as follows:
5′-ATGCATGCATGCATGCATGCA
TGCATGC-3′
Write down the sequence of complementary strand in 5′ -> 3′ direction.