Some previous year
questions from Molecular basis of inheritance..
Structure of DNA
Q. Name the
components a and b in the nucleotide given below: D2008 1
Q. Draw a
labelled diagram of a nucleosome. Where is it found in a cell? F2014
2/3
Or
Q. Draw a
neat labeled diagram of a nucleosome Mention what enables histones to acquire a
positive
charge.
A2012, D2011 2/3
Q. Draw a
schematic representation of dinucleotide. Label the following:
a)the components of a nucleotide b)5’end
c) N-glycosidic linkage d) Phosphodiester linkage. F2010 2/3
Q. Draw a
schematic diagram of a part of double stranded dinucleotide DNA chain having
all the four
nitrogenous bases and showing the correct
polarity. D2012 2/3
Q. Describe the structure of a RNA polynucleotide
chain having 4 different types of nucleotides. D2013 2/3
Q. Explain
the two factors responsible for conferring stability to double helix structure
of DNA. A2014 2
It is established that RNA is the first
genetic material. Explain giving three reasons. D2012
Q. The base
sequence in one of the strands of DNA is TAGCATGAT.
Q, Give the
base sequence of its complementary strand
Q. How are
these base pairs held together in a DNA molecule?
Q. Explain
the base complementarity rules. Name the scientist who framed this rule. D 2011
3
Q. Why is
DNA considered a better hereditary material than RNA? F 2012, A2008
Q. DNA----------—>DNA-------------Ã mRNA-------Ã Protein
Look at the
above sequence and mention the events A , B and C.
Q. What does
central dogma state in molecular biology? How does it differ in some
viruses? D 2009c
2/3
Q. State any
two structural differences and one functional differenc between DNA and RNA F2002
Experiments
Q Describe Griffith’s experiment on Streptococcus pneumonia. Discuss the conclusion he arrived at.
Q Describe
the experiment with Streptococcus
pneumonia that demonstrated the existence of some
transforming principle. A2012, F 2013 3
Q Write the scientific name of the
bacterium used by Friedrick Griffith in his experiment.
How did he prove that some transforming principle
is responsible for transformation of the non
virulent strains of bacteria into the
virulent form?
State the biological nature of transforming
principle.
Name the scientists who proved it. F2011 (5)
Q.Explain
the role of S35 and P32 in the experiments conducted by Hershey and Chase. D 2009C
2/3
Q. Name the
scientists who proved experimentally that DNA is the genetic material. Describe their experiment. F2013 , D2012 3/5
Q. Describe
Alfred Hershey and Martha Chase experiment. Write the conclusion they arrived
at after the experiment. A2014, F2012,D2008, D2009,A2009 5
Q. How did
Hershey and Chase differentiate between DNA and protein in their experiment
while proving that DNA is the genetic material? NCERT
DNA replication
Q.Describe
the experiment that demonstrated the semi- conservative mode of DNA
replication.F2013 2/3
Q.Describe
Meselson and Stahl ‘s experiment and write the conclusion they arrived at.
F2014, D2012
Q.Who
proposed that DNA replication is semi conservative? How was it experimentally
proved by Meselson and Stahl? D2009c
Q. What is
semi conservative DNA replication? How was it experimentally proved and by
whom? A2008,D2002,F2002
Q. Answer the following questions based
on Meselson and Stahl’s experiment:
Write the
nameof the chemical substance used as a source of nitrogen in the experiment by
them.
Why did the
scientists synthesize the light and the heavy DNA molecule in the organism used
in the experiment?
How did the
scientists make it possible to distinguish the heavy DNA molecule from light
DNA molecule? Explain.
Write the
conclusion the scientists arrived at after completing the experiment. A 2011 5
Q. State the
dual role of deoxyribonucleoside triphosphates during DNA replication. F 2013 2/3
Q. Draw a labeled schematic sketch of replication fork of
DNA. Explain the role of the enzymes involved in DNA replication. D 2009
2/3
Q.Explain the process of DNA replication that occurs in a
replication fork in E.coli.
3 A2013
Why do you see two different types of replicating strands in
the given DNA replication fork? Explain. Name these strands. D2011
Name the types of synthesis a and b occurring in the
replication fork of DNA shown below:
D2008
Describe the discontinuous synthesis of DNA D2003
2/3
Name the
enzyme involved in the continuous replication of DNA strand. Mention the
polarity of the template strand. A2010
Name the enzyme and state its property that is responsible
for continuous and discontinuous replication of the two strands of a DNA
molecule. D2013
Transcription
Name the
parts A and B of the transcription unit given below: D2008
Draw a
labeled schematic diagram of a transcription unit. Explain the function of each
component in the unit in the process of transcription. F 2012
2/3 , A2008 5
Draw a
schematic representation of the structure of a transcription unit and show the
following in it:
i.Direction
in which the transcription occurs
ii. Polarity of two strands
iii.Template
strand iv. Terminator gene
Mention the function of promoter gene in transcription. A2009
Construct a complete transcription unit with promoter and
terminator on the basis of the hypothetical template strand given below.
ßATGCATGCATAC—
Write the RNA strand transcribed from the above
transcription unit alongwith its polarity.
D2012
Q.Given
below is a part of the template strand of a structural gene: TAT CAT TAG GAT
Write its
transcribed mRNA strand with its polarity.
Explain the mechanism involved in initiation of
transcription of this strand. D2008
Explain the
process of transcription in a bacterium. F 2012
Describe the initiation/ elongation/ termination process of
transcription in bacteria. D2010 2/3
Explain the
role of RNA polymerase in transcription in bacteria. F2013.
2/3
Describe role of RNA polymerase in transcription in
bacteria (steps)and in eukaryotes(types).F2008 4+
Name the
enzyme responsible for transcription of hn RNA/ tRNA .D2012,A2011 +
Explain the
role of DNA dependent RNA polymerase in initiation, elongation and termination
during transcription in bacterial cell. How is transcription a more complex
process in eukaryotic cells? Explain. F2011
5
Mention the
additional processings which hnRNA needs to undergo after splicing so as to
become functional . D2009, F2012
Describe the
process of synthesis of fully functional mRNA in a eukaryotic cell.
How is this
process of mRNA synthesis different from that in prokaryotes?A2012 5
When and at
what end does the tailing of hnRNA take place? A2009 1
At which ends do capping and tailing of hnRNA occur,
respectively? F 2009 1
Genetic Code
Name the
scientist who suggested that the genetic code should be made of a combination
of three nucleotides. Explain the basis on which he arrived at this conclusion.
D2014 2/3
Mention two functions/ specific features of codon AUG. Give the sequence of bases it is transcribed
from and its anticodon . D2010. A2009, A2013 (2/3)
How many codons will be there in three codons? How many
amino acids will this number of bases code for? F2003
Mention the role of the codons AUG and UGA during protein
synthesis D2011
Three codons on mRNA are not recognized by tRNA , what are
they? What is the general term used for them? What is their significance in
protein synthesis? F2009
Genetic codes can be universal, unambiguous and specific
& degenerate. Write about them, giving one example each. A2013 2+, A2011,
F2012, A2008
Identify giving reasons the salient features of genetic code
by studying the following nucleotide sequenceofmRNA strand and the polypeptide
translated from it
AUG UUU UCU UUU UUU UCU UAG
Met- Phe – Ser –Phe – Phe – Ser D2009c
Translation
Mention the role of ribosomes in peptide bond formation. How
does ATP facilitate it? A2010
Name the scientist who postulated the role of an adaptor in
protein synthesis. Name the adaptor molecule. F2008 , F2014 1+
Q .Name the
scientist who called tRNA molecule as adaptor molecule.
Draw the cloverleaf
structure of a tRNA charged with Methionine(initiator tRNA)/Tyrosine. (F2014 3+)
Anticodon
for this amino acid in its correct site (codon for tyrosine is UCA)
What does the actual structure of tRNA look like? ( F2012)
A2011 3
State the function of following in a prokaryote: tRNA rRNA
A2012, (F2014 1+)
Name the major types of RNA s and explain their role in the
process of protein synthesis in a prokaryote. F2014
Explain the process of translation in a bacterium. F2012
Where does
peptide bond formation occur in a bacterial ribosome and how? F2014
2
How is the translation of mRNA terminated? Explain. D2009
Name the aminoacid that initiator tRNA gets linked
with.Explain the role of initiator tRNA in initiation of protein
synthesis. D2012
What is the function of aminoacyl tRNA synthetase? D2002
Explain aminoacylation of tRNA. A2013
1+
Explain the process of charging of tRNA. Why is it essential
in translation? D2008
How are translational unit and untranslated regions in mRNA
different from each other? A2013 2
Genetic Maps/ DNA
polymorphism
Mention the contribution of genetic maps in human genome
project. A2011
Mention how does DNA polymorphism arise in a population.
D2014 1
Explain DNA
polymorphism as the basis of genetic mapping of human genome.
State the
role of VNTR in DNA fingerprinting
A2013 2/3
Name the
first two steps in DNA Fingerprinting . Describe them briefly. F2002
Explain
thesteps of DNA fingerprinting that will help in processing of the two blood
samples A and B picked up from the crime scene. F2009
5
Lac Operon
Describe how
the Lac Operon operates, both in the presence and absence of an inducer in
E.coli. A 2014
