MCQs For NCERT Class 12 Biology Chapter 6 Molecular Basis of Inheritance

Please refer to the MCQ Questions for Class 12 Biology Chapter 6 Molecular Basis of Inheritance with Answers. The following Molecular Basis of Inheritance Class 12 Biology MCQ Questions has been designed based on the latest syllabus and examination pattern for Class 12. Our experts have designed MCQ Questions for Class 12 Biology with Answers for all chapters in your NCERT Class 12 Biology book.

Molecular Basis of Inheritance Class 12 MCQ Questions with Answers

See below Molecular Basis of Inheritance Class 12 Biology MCQ Questions, solve the questions and compare your answers with the solutions provided below.

Question. The association of histone H₁ with a nucleosome indicates that                               
(a) DNA replication is occurring
(b) the DNA is condensed into a chromatin fibre
(c) the DNA double helix is exposed
(d) transcription is occurring. 

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

Question. Which one of the following does not follow the central dogma of molecular biology?                                 
(a) Pea
(b) Mucor
(c) Chlamydomonas
(d) HIV 

Question. The 3′ – 5′ phosphodiester linkages inside a polynucleotide chain serve to join                                         
(a) one DNA strand with the other DNA strand
(b) one nucleoside with another nucleoside
(c) one nucleotide with another nucleotide
(d) one nitrogenous base with pentose sugar.

Question. Which one of the following statements about the particular entity is true ?                                             
(a) Centromere is found in animal cells, which produces aster during cell division.
(b) The gene for producing insulin is present in every body cell.
(c) Nucleosome is formed of nucleotides.
(d) DNA consists of core of eight histones

Question. Which one of the following pairs of nitrogenous bases of nucleic acids, is wrongly matched with the category mentioned against it?                                             
(a) Guanine, Adenine – Purines
(b) Adenine, Thymine – Purines
(c) Thymine, Uracil – Pyrimidines
(d) Uracil, Cytosine – Pyrimidines 

Question. Which of the following statements is correct?                             
(a) Adenine pairs with thymine through two H-bonds.
(b) Adenine pairs with thymine through one H-bond.
(c) Adenine pairs with thymine through three H-bonds.
(d) Adenine does not pair with thymine.

Question. Purines found both in DNA and RNA are                                     
(a) cytosine and thymine
(b) adenine and thymine
(c) adenine and guanine
(d) guanine and cytosine. 

Question. One turn of the helix in a B-form DNA is approximately                                                 
(a) 2 nm
(b) 20 nm
(c) 0.34 nm
(d) 3.4 nm. 

Question. Which one of the following hydrolyses internal phosphodiester bonds in a polynucleotide chain?               
(a) Lipase
(b) Protease
(c) Endonuclease
(d) Exonuclease

Question. The following ratio is generally constant for a given species:                                         
(a) A + G / C + T
(b) T + C / G + A
(c) G + C / A + T
(d) A + C / T + G. 

Question. In a DNA percentage of thymine is 20% then what will be percentage of guanine?                                       
(a) 20%
(b) 40%
(c) 30%
(d) 60%

Question. Pick the right difference between a DNA and RNA
a) Sugar and phosphate
b) sugar and purines
c) purines and phosphate
d) sugar and pyrimidines

Question.  Select the incorrect statement out of the five given below about lac operon when Lactose is present in the medium.
a) Gene – A gets transcribed into mRNA which produces β-galactoside permease
b) Inducer-Repressor complex is formed
c) Lactose inactivates repressor protein
d) RNA polymerase transcribe Z-gene, Y-gene and A-gene
e) Allolactose is the inducer of lac operon

Question. Wobble position means
a) Base paring
b) altered base on code
b) third altered base on codon
d) none of the above

Question. The percentage of human genome which encodes proteins is approximately
a) Less than 2%
b) 5%
c) 25%
d) 99%

Question. The coding sequences found in split genes are called
a) Operons
b) introns
c) exons
d) cistrons

Question. Match the entries in column I with those of column II and choose the correct answer.
Column I                                    Column II
A) Alkali treatment             M) separation of DNA fragments on gel slab
B) Southern blotting           N) split DNA fragments into single strands
C) Electrophoresis              O) DNA transferred to nitrocellulose sheet
D) PCR                                P) X-ray photography
E) Autoradiography           Q) produce fragments of different sizes
F) DNA treated with REN   R) DNA amplification
(1) A – N, B- Q, C- P, D- R, E- M, F – O
(2) A – P, B – R, C – M, D -O, E – N, F – Q
(3) A – Q, B – O, C – M, D – R, E – P, F – N
(4) A – N, B – O, C – M, D – R, E – P, F – Q

Question. Enzyme which can break and seal the DNA strand
a) Topoisomease II
(b) Helicase
(c) Primase
(d) Restriction endonuclease

Question. The transcription initiation factor associated with the RNA polymerase holoenzyme in prokaryotes is
(a) β
(b) ω
(c) σ
(d) αI

Question. Hershey and Chase experiment proving DNA as the genetic material was based on the principle
a) Transduction
b) transformation
c) transcription
d) translation

Question. The structural genes of lac operon transcribe mRNA which is
a) polycistronic
b) replicative
c) monokaryotic
d) monocistronic

Question.Match the names of scientists in column I with their achievements in column II and choose the correct answer given below
Column I                                   Column II
A) Watson and Crick             P) DNA fingerprinting
B) R.W. Holley                      Q) Decipher genetic code
C) Marshal Nirenberg           R) Double helix of DNA
D) Jacob and Monod             S) Clover model of tRNA
E) Alec Jeffrey                    T) Lac operon concept
   (A)  (B)   (C)  (D)  (E)
a) R    S     P      T    Q
b) R    S     Q     T     P
c) R    Q     P     T     S
d) R    T     S     P     Q

Question. If the sequence of bases in DNA is TACCGACCA, then the sequence of codons on the transcript will be
a) ATGGCTGGT
b) ATCCGAACU
c) AUGGCUGGU
d) AUGGACUAA

Question. Arrange the following events in the order of synthesis of a protein
i) A peptide bond forms
ii) A tRNA matches its anticodon to the codon in the A- site
iii) The movement of second tRNA complex from A-site to P-site
iv) The large subunit attaches to the small subunit and the initiator tRNA fits in the P-site
v) A small subunit binds to the mRNA
vi) The activated amino acid tRNA complex attaches the initiation codon on mRNA
a) iv, v, iii, ii, i, vi
b) iv, vi, v, ii, I, iii
c) v, iv, iii, ii, vi, I
d) v, vi, iv, ii, i, iii

Question. Match the following
Column I                                                      Column II
(A) Helicase                                        (M) activation of amino acid
(B) Peptidyl transferase                    (N) joins DNA fragments
(C) DNA polymerase                          (O) unwinds DNA helix
(D) DNA ligase                                    (P) peptide bonds between amino acids
(E) Aminoacyl synthetase enzyme     (Q) DNA synthesis
(F) RNA primase                                 (R) synthesis of RNA primer
a) A-O, B-P, C-Q, D-N, E-M, F-R
b) A-R, B-M, C-N, D-Q, E-P, F-O
c) A-M, B-R, C-P, D-Q, E-N, F-O
d) A-R, B- Q, C- A, D- M, E-P, F-N

Question. Which of the statements give below is correct with respect to frameshift mutation
a) a single nucleotide base change, insertion, or deletion of the genetic material
b) Glutamine is replaced by valine
c) Sickle cell anemia is an example
d) insertions or deletions of a number of nucleotides in a DNA sequence that is not divisible by three.

Question. Length of one loop of B-DNA                                       
(a) 3.4 nm
(b) 0.34 nm
(c) 20 nm
(d) 10 nm.

Question. DNA is mainly found in                                           
(a) nucleolus
(b) nucleus only
(c) cytoplasm only
(d) none of these. 

Question. Antiparallel strands of a DNA molecule means that                                         
(a) one strand turns clockwise
(b) one strand turns anti-clockwise
(c) the phosphate groups of two DNA strands, at their ends, share the same position
(d) the phosphate groups at the start of two DNA strands are in opposite position (pole).

Question. Which one of the following makes use of RNA template to synthesise DNA?                                         
(a) DNA polymerase
(b) RNA polymerase
(c) Reverse transcriptase
(d) DNA dependant RNA polymerase 

Question. In prokaryotes, the genetic material is                                             
(a) linear DNA without histones
(b) circular DNA without histones
(c) linear DNA with histones
(d) circular DNA with histones. 

Question. In DNA, when AGCT occurs, their association is as per which of the following pair?                                       
(a) AT-GC
(b) AG-CT
(c) AC-GT
(d) All of these 

Question. The eukaryotic genome differs from the prokaryotic genome because                                     
(a) the DNA is complexed with histone in prokaryotes
(b) the DNA is circular and single stranded in prokaryotes
(c) repetitive sequences are present in eukaryotes
(d) genes in the former case are organised into operons. 

Question. Nucleosome core is made of                                       
(a) H₀, H₂A, H₂B and H₃
(b) H₁, H₂A, H₂B, H₄
(c) H1, H₂A, H₂B, H₃ and H₄
(d) H₂A, H₂B, H₃ and H₄. 

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

Question. Nucleotide arrangement in DNA can be seen by                                       
(a) X-ray crystallography
(b) electron microscope
(c) ultracentrifuge
(d) light microscope.

Question. An octamer of 4 histones complexed with DNA forms                                     
(a) endosome
(b) nucleosome
(c) mesosome
(d) centromere.

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

Question. Genes are packaged into a bacterial chromosome by                                         
(a) acidic protein
(b) actin
(c) histones
(d) basic protein.

Question. Radiotracer technique shows that DNA is in                                             
(a) multi-helix stage
(b) single-helix stage
(c) double-helix stage
(d) none of these

Question. Select the correct match.                                         
(a) Ribozyme – Nucleic acid
(b) F₂ × Recessive parent – Dihybrid cross
(c) T.H. Morgan – Transduction
(d) G. Mendel – Transformation

Question. The final proof for DNA as the genetic material came from the experiments of                                     
(a) Hershey and Chase
(b) Avery, MacLeod and McCarty
(c) Hargobind Khorana
(d) Griffith. 

Question. Taylor conducted the experiments to prove semiconservative mode of chromosome replication on           
(a) Vinca rosea
(b) Vicia faba
(c) Drosophila melanogaster
(d) E. coli.

Question. Semi-conservative replication of DNA was first demonstrated in                                           
(a) Escherichia coli
(b) Streptococcus pneumoniae
(c) Salmonella typhimurium
(d) Drosophila melanogaster. 

Question. Transformation experiment was first performed on which bacteria?                                   
(a) E. coli
(b) Diplococcus pneumoniae
(c) Salmonella
(d) Pasteurella pestis

Question. The Pneumococcus experiment proves that                                                   
(a) bacteria do not reproduce sexually
(b) RNA sometime controls the production of DNA and proteins
(c) DNA is the genetic material
(d) bacteria undergo binary fission. 

Question. DNA synthesis can be specifically measured by estimating the incorporation of radio-labelled                   
(a) thymidine
(b) deoxyribose sugar
(c) uracil
(d) adenine. 

Question. Transformation was discovered by                                         
(a) Meselson and Stahl
(b) Hershey and Chase
(c) Griffith
(d) Watson and Crick.

Question. The unequivocal proof of DNA as the genetic material came from the studies on a                                   
(a) bacterium
(b) fungus
(c) viroid
(d) bacterial virus.

Question. The transforming principle of Pneumococcus as found out by Avery, MacLeod and McCarty was               
(a) mRNA
(b) DNA
(c) protein
(d) polysaccharide. 

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.

Question. During DNA replication, Okazaki fragments are used to elongate                                       
(a) the lagging strand towards replication fork
(b) the leading strand away from replication fork
(c) the lagging strand away from the replication fork
(d) the leading strand towards replication fork.

Question. During replication of a bacterial chromosome DNA synthesis starts from a replication origin site and         
(a) RNA primers are involved
(b) is facilitated by telomerase
(c) moves in one direction of the site
(d) moves in bidirectional way. 

Question. Method of DNA replication in which two strands of DNA separate and synthesise new strands is called     
(a) dispersive
(b) conservative
(c) semi-conservative
(d) non conservative.

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. 

Question. Who proved that DNA is basic genetic material?                                     
(a) Griffith
(b) Watson
(c) Boveri and Sutton
(d) Hershey and Chase

Question. Which one of the following is not applicable to RNA?                                   
(a) Heterocyclic nitrogenous bases
(b) Chargaff’s rule
(c) Complementary base pairing
(d) 5’ phosphoryl and 3’ hydroxyl ends 

Question. During DNA replication, the strands separate by                                           
(a) DNA polymerase
(b) topoisomerase
(c) unwindase/helicase
(d) gyrase. 

Question. Experimental material in the study of DNA replication has been                                           
(a) Escherichia coli
(b) Neurospora crassa
(c) Pneumococcus
(d) Drosophila melanogaster.

Question. DNA replication is                                                 
(a) conservative and discontinuous
(b) semi-conservative and semi-discontinuous
(c) semi-conservative and discontinuous
(d) conservative.

Question. Name the enzyme that facilitates opening of DNA helix during transcription.                                     
(a) DNA ligase
(b) DNA helicase
(c) DNA polymerase
(d) RNA polymerase

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.

Question. Spliceosomes are not found in cells of                                           
(a) fungi
(b) animals
(c) bacteria
(d) plants. 

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