- Portion of DNA called cistron specifies the formation of a
particular polypeptide.
Match The columns- Match Column I with Column II.
Column I Column II
A. Gene (i) Alec Jeffreys
B. DNA fingerprinting (ii) Coding sequences
C. Exons (iii) Johanssen
D. tRNA (iv) Transposons
E. Jumping genes (v) Adapter molecule - Match Column I with Column II. (There can be more than
one match for items in Column I)
Column I Column II
A. Initiation codon (i) UAA
B. Stop codon (ii) AUG
C. Ribosome (iii) 70S
D. Operon system (iv) GUG
E. Nitrogenous base (v) UAG
(vi) 80S
(vii) Lac
(viii) Tr p
(ix) Adenine
(x) Thymine
passage Based Questions23.(A) Complete the given passage with appropriate words or
phrases.
Double helix model for the structure of DNA was proposed
by (i) and (ii) in year (iii) , based on the (iv) data
produced by (v) and (vi). One of the hallmarks of
their proposition was (vii) between the two strands
of polynucleotide chains. However, this proposition was
also based on the observation of (viii) that for a double
stranded DNA, the ratios between adenine and (ix) and
guanine and (x) are constant and equals to one.
(B) Read the given passage and correct the errors, wherever
present.
Translation refers to the process of polymerisation of
nucleotides to form amino acids. The order and sequences
of amino acids are defined by the sequences of bases in the
tRNA. Eukaryotic translation occurs on 70S ribosomes. It is
a discontinuous process as transcription occurs in cytoplasm
while translation takes place in nucleus.
Assertion & reason
In each of the following questions, a statement of Assertion
(A) is given and a corresponding statement of Reason (R)
is given just below it. Of the statements, mark the correct
answer as :
(a) if both A and R are true and R is the correct explanation
of A
(b) if both A and R are true but R is not the correct explanation
of A
(c) if A is true but R is false
(d) if both A and R are false.- Assertion : One gene one enzyme hypothesis was
changed into one gene one polypeptide hypothesis.
Reason : The synthesis of the two types of polypeptides
is controlled by two different genes situated on same
chromosome. - Assertion : mRNA is called informational or genetic
RNA.
Reason : mRNA brings instructions from the DNA for
the formation of a particular type of polypeptide. - Assertion : In replication, only a small portion of DNA
molecule unwinds for separating the segments of DNA
strands.
Reason : Only one strand functions as template in
replication. - Assertion : The opposite strands of DNA chains are
not identical but complementary to each other.
Reason : Specific base pairing occurs between a
purine lying opposite to a pyrimidine. - Assertion : DNA Polymorphism is the basis for
genetic mapping of human genome as well as DNA
fingerprinting.
Reason : Polymorphism in DNA arises due to
mutations.
Figure Based Questions- Refer to the given figure and answer the following
questions.
(a) Identify A, B, X, Y and Z in the given figure.
(b) Briefly describe the function of A.
(c) Which labelled part is involved in hydrolysing the
lactose?