Chapter-6 Molecular Basis of Inheritance

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

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

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

Define an operon. giving an example, explain an Inducible operon.

Discuss the process of translation in detail.

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

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.

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?

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

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?

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

What background information did Watson and Crick have made available
for developing a model of DNA? What was their contribution?

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?

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

Now, sequencing of total genomes getting is getting 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?

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

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

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

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.

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.

Recall the experiments done by Frederick Griffith, Avery, MacLeod and
McCarty, where DNA was speculated to be the genetic material. If RNA,
instead of DNA was the genetic material, would the heat killed
strain of Pneumococcus have transformed the R-strain into virulent
strain? Explain.

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?

Retroviruses do not follow central Dogma. Comment.

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 (d NTPs) play?

Give any six features of the human genome.

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

Discuss the significance of heavy isotope of nitrogen in the Meselson
and Stahl’s experiment.

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

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

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

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

In a nucleus, the number of ribonucleoside triphosphates is 10 times
the number of deoxy x10 ribonucleoside triphosphates, but only deoxy
ribonucleotides are added during the DNA replication. Suggest a
mechanism.

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.

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

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

Given below is the sequence of coding strand of DNA in a transcription
unit
3 'A A T G C A G C T A T T A G G – 5’
write the sequence of
a) its complementary strand
b) the mRNA

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?

What is the cause of discontinuous synthesis of DNA on one of the
parental strands o

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

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

What is the function of histones in DNA packaging?

Who performed the blender experiment? What does this experiment
prove? Describe the steps followed in this experiment?

Define bacterial transformation? Who proved it experimentally & how?

What are the three types of RNA & Mention their role in protein Synthesis?

Why it is that transcription & translation could be coupled in prokaryotic
cell but not in eukaryotic cell?

Mention any four important characteristics of genetic code.

Why is DNA & not RNA is the genetic material in majority of organisms?

Mention the dual functions of AUG?

What is the base pairing pattern of DNA?

Name the three non-sense codons?

Where do transcription & translation takes place in a prokaryotic cell?
Describe the three steps involved in translation?

Describe the continuous & discontinuous Synthesis of DNA?

A tRNA is charged with amino acid methionine.
i) At what site in the ribosome will the tRNA bind?
ii) Give the anticodon of this tRNA?
iii) What is the mRNA codon for methionine?
iv) Name the enzyme responsible for this binding?

Why is human Genome project considered as mega project?

Give two reasons why both the strands are not copied during transcription?

What do you mean by “Central Dogma of Molecular genetics?”

What is a codon?

Who experimentally prove that DNA replication is semi conservative.

Name the enzyme which helps in formation of peptide bond?

What do you mean semi conservative nature of DNA replication. Who
proved it & how?

The length of DNA in an eukaryotic cell is N 2.2 m How can such a huge
DNA be packaged in a nucleus of micrometer in diameter.

Two claimant fathers filed a case against a lady claiming to be the father of
her only daughter. How could this case be settled identifying the real
biological father?

Explain what happens in frameshift mutation? Name one disease caused
by the disorder?

What is peptide bond? How is it formed?

Why is it essential that tRNA binds to both amino acids & mRNA codon
during protein synthesis?

Name the enzyme that joins the short pieces in the lagging strand during
synthesis of DNA?

What is point mutation?

What is the function of amino acyl tRNA synthetase.

What is an operon? Describe the major steps involved in an operon?

The base sequence on one strand of DNA is ATGTCTATA
i) Give the base sequence of its complementary strand.
ii) If an RNA strand is transcribed from this strand what would be the
base sequence of RNA?
iii) What holds these base pairs together?

What is transformation? Describe Grifith’s experiment to show transformation?
What did he prove from his experiment?

Give two reasons why both the strands of DNA are not copied during DNA
transcription?

Three codons on mRNA are not recognised by tRNA what are they? What is the
general term used for them what is their significance in protein synthesis?

“DNA polymerase plays a dual function during DNA replication” comment on
statement?

In which direction, the new strand of DNA synthesised during DNA replication.

Give the initiation codon for protein synthesis. Name the amino acid it codes
for?

Name the process in which unwanted mRNA regions are removed & wanted
regions are joined.

Name the process in which unwanted mRNA regions are removed & wanted
regions are joined.

Briefly describe the following:

(a) Transcription

(b) Polymorphism

(c) Translation

(d) Bioinformatics

What is DNA fingerprinting? Mention its application.

Why is the Human Genome project called a mega project?

Explain (in one or two lines) the function of the followings:

(a) Promoter

(b) tRNA

(c) Exons

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?

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?

List two essential roles of ribosome during translation.

Differentiate between the followings:

(a) Repetitive DNA and Satellite DNA

(b) mRNA and tRNA

(c) Template strand and Coding strand

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

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.

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

If the sequence of the coding strand in a transcription unit is written as follows:

5'-ATGCATGCATGCATGCATGCATGCATGC-3'

Write down the sequence of mRNA

If the sequence of one strand of DNA is written as follows:

5'-ATGCATGCATGCATGCATGCATGCATGC-3'

Write down the sequence of complementary strand in 5' → 3' direction

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

Group the following as nitrogenous bases and nucleosides:

Adenine, Cytidine, Thymine, Guanosine, Uracil and Cytosine