MOLECULAR BASIS OF INHERITANCE
2010 MARCH
a. Complete
the flow chart given below and answer the following questions (2)
b. Mention
principles behind the DNA fingerprinting. (1)
c. DNA
fingerprinting is a gift to forensic science. Do you agree? Give reason. (1)
2. Diagram
of a double stranded polynucleotide chain is shown below. What do the numbers
I, II, III & IV indicate? (2)
2010 SAY
1. The
figure given below is that of a nucleosome.
a. Name
the parts labeled as (i) and (ii) (1)
b. How
many histone units constitute the main core of the nucleosome? (1)
c. Histones
are considered as basic proteins. Why? (1)
2. During
the eukaryotic transcription, the genetic information encoded in the DNA will
be transferred to mRNA. The mRNA thus formed will be processed and utilized in
synthesis of protein.
a. Both
DNA strands are not copied during transcription. Why? (1)
b. What
do template & coding DNA strands represent? (1)
c. What
will be the result, if RNA is not spliced before translation? (1)
2011 MARCH
1.
Observe the diagram below
Which among the
following is the complimentary sequence of the DNA fragment shown above? (½)
a. 5’
→ ATTCG → 3’ b. 3’ → ATTCG
→ 5’
c. 3’
→ TAAGC → 5’ d. 3’ → CGAAT → 5’
2. A
DNA sequence is provided below: TACGAGTTATATATACAT
a. Write
down the triplet codon it codes for. (½)
b. If
a nitrogen base is added in between 4th and 5th nitrogen bases, what will be its effect on
transcription? (1)
3. In
a paternity dispute, the VNTR DNA samples of parent and child were DNA
fingerprinted. The diagrammatic representation of the DNA fingerprint is shown
below.
a. What
is your opinion about the paternity of child? Substantiate your opinion. (1)
b. List
down any four major steps of molecular biological procedures adopted for this.
(2)
c. What
do you understand by VNTRs? (½)
d. Who
developed this technique for the first time? (½)
2011 SAY
1.
A DNA molecule which contains
most of its nitrogen in the form of 15N is allowed to replicate in a
medium containing the nitrogen source 14N.
a. What
will be the percentage of DNA strands that contain 15N after 2
rounds of replication? (1)
b. Who
conducted this experiment and what conclusion they reached from this
experiment? (1)
2. Central
dogma of molecular biology is given in the diagram.
a. What
do A, B and C stand for? (1)
b. In
which organisms, the central dogma is reversed? (1)
3. Given
below is the diagram of a replication fork drawn by a student.
a. Redraw
the diagram correctly and label it. (½)
b. Why
does discontinuous synthesis of DNA occur in one strand? (1½)
2012 MARCH
1. A transcription unit is given below. Observe it and
answer the questions.
a.
How
can you identify the coding strand? (1)
b.
Write
the sequence of RNA formed from this unit. (1)
c.
What
would happen if both strands of the DNA act as template for transcription? (1)
2.
In E.
coli, lactose catabolism is controlled by Lac operon. Lac operon in the
absence of inducer (lactose) is given below.
a.
What
is ‘P’? (½)
b.
Name
the enzymes produced by the structural genes ‘Z’, ‘Y’ & ‘a’. (1½)
c.
Redraw
the diagram in the presence of an inducer. (1)
2012 SAY
1.
Following are the first two
steps in Griffith’s transformation experiment.
i. S-strain
→ inject into mice → mice live
ii. R-strain
→ inject into mice → mice die
a. If
there is any mistake, correct it. (½ )
b. Write
the remaining steps. (1)
2. DNA
is better genetic material than RNA. Do you agree with this statement?
Substantiate. (1½)
3. Given
below is the diagrammatic representation of first stage of a process in bacteria.
a. Identify
the process. (½)
b. Name
the enzyme which catalyzes this process. (½)
c. What
are the additional complexities in eukaryotes for this process? (2)