CBSE Class 12 Biology Molecular Basis of Inheritance MCQs Set B

Question. A sequence of DNA to be transcribed is 5’ATTGCCATT3’ coding strand 3’TAACGGTAA5’ template strand. Give the sequence of RNA transcribed
a) 5’ATTGCCATT3’
b) 3’UAACGGUAA5’
c) 5’UAACGGUAA3’
d) 5’AUUGCCAUU3’

Answer : D

Question. Which RNA Brings amino acids and reads genetic code?
a) t–RNA
b) r–RNA
c) m–RNA
d) None of the above

Answer : A

Question. A DNA with unequal nitrogen bases would most probably be
a) single stranded
b) double stranded
c) triple stranded
d) four stranded.

Answer : A

Question. The experimental proof for semi-conservative replication of DNA was first shown in a
a) fungus
b) bacterium
c) plant
d) virus.

Answer : B

Question. Sickle cell anemia is caused
a) When valine is replaced by glutamic acid in beta polypeptide chain
b) When glutamic acid is replaced by valine in beta polypeptide chain
c) When glutamic acid is replaced by valine in alpha polypeptide chain
d) When valine is replaced by glutamic acid in alpha polypeptide chain

Answer : B

Question. Teminism is
a) a central dogma reverse
b) a central dogma of molecular biology
c) a circular flow of hereditary material
d) an effect of cytoplasm on functioning of DNA

Answer : A

Question. The total number of nitrogenous bases in human genome is estimated to be about
a) 3.5 million
b) 35 thousand
c) 35 million
d) 3.1 billion

Answer : D

Question. In an inducible operon, the genes are
a) usually not expressed unless a signal turns them”on”.
b) usually expressed unless a signal turns them “off”.
c) never expressed
d) always expresser.

Answer : A

Question. What is it that forms the basis of DNA finger-printing?
a) The relative proportions of purines and pyrimidine in DNA.
b) The relative difference in the DNA occurrence in blood, skin and saliva.
c) The relative amount of DNA in the ridges and grooves of the fingerprints.
d) Satellite DNA occurring as highly repeated short DNA segments.

Answer : D

Question. DNA-dependent RNA polymerase catalyses transcription on one strand of the DNA which is called the
a) template strand
b) coding strand
c) alpha strand
d) antistrand.

Answer : A

Question. What is not True for DNA in prokaryotes
a) present in the form of a compact structure called nucleoid
b) the coils are maintained by non-histone basic proteins
c) found in cytoplasm in a supercoiled condition
d) packaged as nucleosomes along with histones

Answer : D

Question. A bacterial colony containing DNA made up of 100% N15 nitrogen bases is allowed to replicate in a medium containing N14 bases. After one round of replication the result would be
a) All individuals will be identical to parents
b) All individuals will be hybrids
c) Only 50% individuals would be hybrids
d) All individuals would have DNA made up of 100% N14

Answer : B

Question. Similarity in DNA and RNA is that
a) both are polymer of nucleotides
b) both have similar pyrimidine
c) both have similar sugar
d) both are genetic material.

Answer : A

Question. There are special proteins that help to open up DNA double helix in front of the replication fork. These proteins are
a) DNA ligase
b) DNA topoisomerase I
c) DNA gyrase
d) DNA polymerase I.

Answer : B

Question. Function of t RNA is
a) To bring the aminoacids
b) To read the genetic code
c) Both a) and b)
d) To give catalytic property

Answer : C

Question. RNA polymerase requires which factor for initiation
a) Rho
b) Alpha
c) Sigma
d) Pi

Answer : C

Question. Which of the following features of genetic code does allow bacteria to produce human insulin by recombinant DNA technology?
a) Genetic code is specific.
b) Genetic code is not ambiguous.
c) Genetic code is redundant.
d) Genetic code is nearly universal.

Answer : D

Question. Which one of the following is the starter codon?
a) UAA
b) UAG
c) AUG
d) UGA

Answer : C

Question. Select the correct statement.
a) Franklin Stahl coined the term ‘‘linkage’’.
b) Punnett square was developed by a British scientist.
c) Spliceosomes take part in translation.
d) Transduction was discovered by S. Altman.

Answer : B

Question. The equivalent of a structural gene is
a) muton
b) cistron
c) operon
d) recon.

Answer : B

Question. Which one of the following pairs of codons is correctly matched with their function or the signal for the particular amino acid?
a) AUG, ACG – Start/methionine
b) UUA, UCA – Leucine
c) GUU, GCU – Alanine
d) UAG, UGA – Stop

Answer : D

Question. What are the structures called that give an appearance as ‘beads-on-string’ in the chromosomes when viewed under electron microscope?
a) Genes
b) Nucleotides
c) Nucleosomes
d) Base pairs

Answer : C

Question. Genetic code consists of
a) adenine and guanine
b) cytosine and uracil
c) cytosine and guanine
d) all of these.

Answer : D

Question. A complex of ribosomes attached to a single strand of RNA is known as
a) polypeptide
b) Okazaki fragment
c) polysome
d) polymer

Answer : C

Question. The process of transfer of genetic information from DNA to RNA/formation of RNA from DNA is
a) transversion
b) transcription
c) translation
d) translocation.

Answer : B

Question. Which one of the following triplet codes, is correctly matched with its specificity for an amino acid in protein synthesis or as ‘start’ or ‘stop’ codon ? D
a) UCG – Start
b) UUU – Stop
c) UGU – Leucine
d) UAC – Tyrosine

Answer : D

Question. Telomerase is an enzyme which is a
a) simple protein
b) RNA
c) ribonucleoprotein
d) repetitive DNA.

Answer : C

Question. In operon concept, regulator gene functions as
a) inhibitor
b) repressor
c) regulator
d) all of these.

Answer : B

Question. In a nucleotide, the nitrogen base is joined to the sugar molecule by
a) Phosphodiester bond
b) Glycosidic bond
c) Hydrogen bond
d) a) &b)

Answer : B