100+ Molecular Basis of Inheritance NEET Questions and Answers

Are you looking for Molecular Basis of Inheritance Questions and Answers for NEET and other medical entrance examinations? If yes, these are some most important multiple choice questions and answers on NCERT Class-12 Biology, Chapter-6 (Molecular Basis of Inheritance).

Here we composed these 100+ MCQs and Answers on the Molecular Basis of Inheritance after reading the chapter on Molecular Basis of Inheritance from the NCERT book on Class 12 Biology. The questions are topics-wise and the students can relate the questions easily to the most important topics of this chapter.

Molecular Basis of Inheritance NEET Questions with Answers

DNA MCQ and Answers

1. Who was the first person to analyse factors?

a) Gross

b) Haeckel

c) Mendel

d) Altmann

Answer: c


2. In which year, the mechanism for genetic inheritance reached the molecular level?

a) 1986

b) 1999

c) 1926

d) 1945

Answer: c


3. What is the full form of DNA?

a) Degenerative acid

b) Deoxyribonucleic acid

c) Deadly nucleic acid

d) Disoriented acid

Answer: b


4. How many types of nucleic acids are present in the living systems?

a) One

b) Two

c) Three

d) Four

Answer: b


5. Which of the following is not a function of RNA?

a) Messenger

b) Catalysis

c) Adapter

d) Modifier

Answer: d


6. Which of the following is not a correct statement with respect to DNA?

a) It is a long polymer

b) It is found in the nucleus

c) It is a basic substance

d) First identified by Friedrich Meischer

Answer: c


7. Which of the following is the characteristic feature of an organism?

a) Number of RNA

b) Number of protein molecules

c) Length of chromosomes

d) Length of DNA

Answer: d


8. How many numbers of nucleotides are present in Lambda phage?

a) 48502 bp

b) 98526 bp

c) 10000 bp

d) 5326 bp

Answer: a


9. Which of the following is correct with respect to the genetic material of Φ174 bacteriophage?

a) ss DNA, linear

b) ss RNA, linear

c) ss DNA, circular

d) ds DNA, linear

Answer: c


10. How many components are present in the basic unit of DNA?

a) One

b) Two

c) Three

d) Four

Answer: c


11. Which of the following statements is correct with respect to purines?

a) Purines are heterocyclic compounds

b) Purines are 7 membered structure

c) Purines are single-ring structure

d) Thymine is an example of purine

Answer: a


12. Which of the following statement is incorrect with respect to pyrimidines?

a) Heterocyclic

b) 7 membered ring

c) Cytosine is an example of pyrimidine

d) Single-ring structure

Answer: b


13. By which of the following bonds, a nitrogenous base is linked to the pentose sugar?

a) Phosphate bond

b) Ester bond

c) Peptide bond

d) N-glycosidic bond

Answer: d

Structure of a Polynucleotide Chain MCQ and Answers

14. Through which among the following linkages are the two nucleotides connected through the 3’-5’ end?

a) Phosphodiether linkage

b) Phosphodisulphide linkage

c) Phosphodinitrate linkage

d) Phosphodiester linkage

Answer: d


15. What is chemical name for thymine known as?

a) 5-methoxy uracil

b) 3-methoxy uracil

c) 5-methyl uracil

d) 3-methy uracil

Answer: c


16. Who considered DNA as a “Nuclein”?

a) James Watson

b) Friedrich Meischer

c) Francis Crick

d) Rosalind Franklin

Answer: b


17. Which among the following is the exact ratio of guanine to cytosine in a DNA double helical structure?

a) 3:2

b) 2:1

c) 1:3

d) 1:1

Answer: d


18. Which of the following enzymes are used to transcript a portion of the DNA into mRNA?

a) RNA polymerase

b) DNA polymerase

c) Protein polymerase

d) Hydrolase

Answer: a


19. Which is the correct complementary strand for AGAATTCGC?

a) CTCCGGATA

b) GAGGCCTAT

c) TCTTAAGCG

d) GTGGCCATA

Answer: c


20. Which of the following occurs in the process of central dogma reverse?

a) Conversion of a strand of mRNA to DNA

b) Changes in the chromosomal karyotype

c) Gene replication process

d) Protein production process

Answer: a


21. Which of the following ensures the stability of the helical structure of a DNA?

a) Presence of repetitive structures of a DNA code

b) Stacking of one base pair over the other

c) Presence of aneuploidy

d) Occurrence of chromosomal rearrangements

Answer: b


22. Which of the following is not a part of the nucleotide?

a) Phosphate group

b) Nitrogenous base

c) Pentose sugar

d) Guanosine

Answer: d


23. What will be the next step in the process of transcription?

DNA -> RNA ->?

a) mRNA

b) tRNA

c) rRNA

d) Protein

Answer: d

Packaging of DNA Helix MCQ and Answers

24. What is the length of the DNA double helix, if the total number of bp (base pair) is 6.6 x 109?

a) 2.2 m/bp

b) 2.5 m/bp

c) 2.2 m

d) 2.5 m

Answer: c


25. What are the set of positively charged basic proteins called as?

a) Histidine

b) DNA

c) RNA

d) Histones

Answer: d


26. What are the thread-like stained structures present in the nucleus known as?

a) Chromosome

b) Chromatid

c) Chromatin

d) Chloroplast

Answer: c


27. How many bp are present in a typical nucleosome?

a) 200 bp

b) 100 bp

c) 300 bp

d) 90 bp

Answer: a


28. When the negatively charged DNA combines with the positively charged histone octamer, which of the following is formed?

a) Nucleus

b) Nucleoid

c) Nucleosome

d) Nucleosome

Answer: c


29. How many nucleosomes are present in a mammalian cell?

a) 20 million

b) 30 million

c) 40 million

d) 10 million

Answer: b


30. Which of the following chromatins are said to be transcriptionally active and inactive respectively?

a) Euchromatin, Heterochromatin

b) Euchromatin, Prochromatin

c) Prochromatin, Euchromatin

d) Heterochromatin, Euchromatin

Answer: a


31. What are the additional set of proteins which are required for the packaging of chromatin at the higher levels known as?

a) Histone proteins

b) Non-Histone proteins

c) Histone chromosomal proteins

d) Non-Histone chromosomal proteins

Answer: d


32. What is the typical distance between two base pairs in nm?

a) 0.34 nm

b) 0.32 nm

c) 0.33 nm

d) 0.35 nm

Answer: a

The Search for Genetic Material MCQ and Answers

33. Which of the following bacterium is responsible for causing pneumonia?

a) Staphylococcus saprophyticus

b) Streptococcus pyogenes

c) Staphylococcus aureus

d) Streptococcus pneumoniae

Answer: d


34. When Streptococcus pneumoniae were cultured in a culture plate by Frederick Griffith, which among the following were produced?

a) Smooth colonies(S) and Rough colonies (R)

b) Shiny colonies (S) and Rough colonies (R)

c) Smooth colonies (S) and Rigorous colonies (R)

d) Silky colonies (S) and Rigorous colonies (R)

Answer: b


35. Which of the following is the wrong sequential order, when the S or the R strain of the bacterium is injected into the mice?

a) Mice -> S strain -> Dead

b) Mice -> R strain -> Alive

c) Mice -> Heat killed S strain -> Alive

d) Mice -> Heat killed S strain + live R strain -> Alive

Answer: d


36. Which of the following is responsible for transforming the R strain into the S strain?

a) Purified bio-chemicals from S-strain

b) Purified bio-chemicals from R-strain

c) Purified bio-chemicals from heat killed S-strain

d) Purified bio-chemicals from heat killed R-strain

Answer: c


37. Which of the following is responsible for the inhibition of transformation in organisms?

a) DNase

b) RNase

c) Protease

d) Nuclease

Answer: a


38. What will be the state of the mouse that has been injected with the heat killed S-strain from the Staphylococcus pneumoniae?

a) Alive

b) Dead

c) On the verge of dying

d) Lives with pneumonia

Answer: a


39. Which was considered to be as the genetic material prior to the works done by Oswald Avery, Colin MacLeod and Maclyn McCarty?

a) Nucleoids

b) Nucleons

c) Protein

d) Chromosome

Answer: c

The Genetic Material is DNA MCQ and Answers

40. What are the viruses that affect bacteria known as?

a) Virophage

b) Bacteriophage

c) Mimivirus

d) Virology

Answer: b


41. Who proved that DNA was indeed the genetic material through experiments?

a) Alfred Hershey and Maclyn McCarty

b) Oswald Avery and Maclyn McCarty

c) Oswald Avery and Martha Chase

d) Alfred Hershey and Martha Chase

Answer: d


42. On which medium were the viruses cultivated by Alfred Hershey and Martha Chase?

a) A medium containing radioactive potassium (K)

b) A medium containing radioactive Uranium (U)

c) A medium containing radioactive phosphorous (P)

d) A medium containing potassium (K)

Answer: c


43. Which of the following is not a stage in the “Hershey-Chase experiment”?

a) Blending

b) Centrifugation

c) Infection

d) Conjugation

Answer: d


44. Which of the following can be observed alongside with radioactive bacterium as a result of centrifugation?

a) Bacterium starts to produce RNA

b) Radioactivity can be detected in the supernatant

c) Bacterium starts to move slow

d) Radioactivity cannot be detected in the supernatant

Answer: d


45. What will happen when the radioactive protein capsule of the virus is attached onto the bacteria?

a) Radioactivity is detected in the supernatant

b) Radioactivity is absent in the supernatant

c) Radioactive DNA is injected into the bacterium

d) Attachment of the virus to the bacterium doesn’t occur

Answer: a

Properties of Genetic Material (DNA vs RNA) MCQ and Answers

46. Which of the following criterion needn’t be fulfilled by the genetic material?

a) Occurrence of replication

b) Should be able to express itself in the form of “Bohr’s characters”

c) Provision of scope for the mutation that is required for evolution

d) It should be chemically and structurally stable

Answer: b


47. Which of the following is not a characteristic of RNA?

a) It has ribose sugar molecules in the nucleotides

b) It is a single stranded molecule

c) It is not stable under alkaline conditions

d) All the 3 types of RNA are involved in protein synthesis

Answer: c


48. Which of the following criterion cannot be fulfilled by protein?

a) Formation of polypeptide chains

b) Generation of its replica

c) Formation of alpha helix and beta sheets

d) Non covalent bonds are present between amino acids

Answer: b


49. What will happen when the 2 complementary strands of the DNA are heated up and brought together?

a) They will repel each due to the charges formed

b) They will attract each other due to the charges formed

c) They will become non-complementary to each other

d) They will combine with each other under appropriate conditions

Answer: d


50. Which of the following statements is correct regarding DNA and RNA?

a) DNA is highly reactive

b) RNA is not catalytic

c) RNA cannot be easily degraded

d) DNA is a better genetic material than RNA

Answer: d


51. At what rate does the RNA mutate as compared to DNA?

a) Faster rate

b) Slower rate

c) Moderate rate

d) Depending on the medium

Answer: a


52. RNA codes are used for translation into which of the following?

a) Genes

b) DNA

c) Proteins

d) Carbohydrate

Answer: c


53. Which of the following is responsible for the transmission of genetic information?

a) DNA

b) RNA

c) Proteins

d) Mitochondrion

Answer: b


54. Which of the following is responsible for the storage of genetic material?

a) DNA

b) RNA

c) Proteins

d) Ribosome

Answer: a

The Experimental Proof of Replication of DNA MCQ and Answers

55. Which process is termed as “semiconservative DNA replication”?

a) Presence of only newly synthesised strands in DNA

b) Presence of only parental strands in DNA

c) Presence of both parental and newly synthesised strands in DNA

d) Presence of a hybrid variety of strands

Answer: c


56. In which organism was the “Semiconservative theory of DNA replication” first observed?

a) Treponema pallidum

b) Vibrio cholerae

c) Staphylococcus pneumoniae

d) Escherichia coli

Answer: d


57. Which of the following is the heavy isotope of nitrogen?

a) 14N

b) 15N

c) 13N

d) 16N

Answer: b


58. Which organism was used to detect the presence of thymidine on the newly formed DNA in 1958?

a) Vivrio cholerae

b) Treponema pallidum

c) Vicia faba

d) Escherichia coli

Answer: c

The Machinery and the Enzymes for Replication of DNA MCQ and Answers

59. Which enzyme is used for the process of replication in E. Coli?

a) Restriction enzyme

b) Protease enzyme

c) Lipase enzyme

d) DNA polymerase

Answer: d


60. How long does it take for E. Coli to replicate?

a) 10 minutes

b) 20 minutes

c) 18 minutes

d) 21 minutes

Answer: c


61. What will happen if any abnormal changes or mistakes occur during the process of replication?

a) Mutation

b) Normal cell growth

c) Unpredictable cell deaths

d) Rapid formation of new cells

Answer: a


62. In which type of process, can replication be seen at the small opening of the DNA?

a) Transformation

b) Incision

c) Mutation

d) Replication fork

Answer: d


63. In which direction do the DNA dependent DNA polymerases catalyse the polymerization reaction?

a) 3’ → 5’

b) 5’ → 3’

c) In both the directions

d) Is not direction dependent

Answer: b


64. In which phase of the cell cycle does the process of replication take place in E.coli?

a) The M phase

b) The G1 phase

c) The G2 phase

d) The S phase

Answer: d


65. What does the failure of cell division after DNA replication result in?

a) Polyploidy

b) Aneuploidy

c) Apoptosis

d) Migration of cells

Answer: a

Transcription Basics MCQ and Answers

66. What is the process of copying genetic information from a single strand of DNA into an RNA known as?

a) Translation

b) Transcription

c) Reverse transcription

d) Reverse translation

Answer: b


67. Which of the following is not a transcription unit of the DNA?

a) Terminator

b) Promoter

c) Organiser

d) Structural gene

Answer: c


68. In which direction does the DNA dependent RNA polymerase catalyse the polymerisation reaction?

a) 3’ → 5’

b) Bidirectional

c) Direction is dependent on the medium

d) 5’ → 3’

Answer: d


69. Which of the following is the initial “start site“ for the process of transcription?

a) Promoter

b) Terminator

c) Organiser

d) Structural gene

Answer: a

Transcription Unit and the Gene MCQ and Answers

70. What is a cistron?

a) A gene coding for RNA

b) A segment of DNA responsible for producing the nuclear coat

c) A segment of DNA coding for polypeptides

d) A gene coding for the template strand of DNA

Answer: c


71. Which of the following is monocistronic?

a) Fungi

b) Eukaryotes

c) Bacteria

d) Virus

Answer: b


72. Which of the following is polycistronic?

a) Bacteria

b) Rats

c) Snakes

d) Hamster

Answer: a

Types of RNA and Process of Transcription in Prokaryotes MCQ and Answers

73. Which of the following is not a type of RNA?

a) mRNA

b) tRNA

c) rRNA

d) sRNA

Answer: d


74. What is the role of tRNA?

a) It provides the template strand

b) It brings the amino acids and reads the genetic code

c) It plays a catalytic role during translation

d) It plays a structural role during translation

Answer: b


75. Which of the following enzyme binds to the promoter and initiates the process of transcription?

a) DNA polymerase

b) Lipase

c) RNA polymerase

d) Lysozyme

Answer: c


76. What happens when the polymerase enzyme reaches the terminator region during transcription?

a) The nascent RNA falls off

b) The nascent DNA falls off

c) The nascent protein falls off

d) The nascent enzyme falls off

Answer: a


77. Which of the following stage is catalyzed by the RNA polymerase enzyme?

a) Initiation

b) Elongation

c) Termination

d) Monocistronic

Answer: b

Process of Transcription in Eukaryotes MCQ and Answers

78. What is the role of RNA polymerase III?

a) Transcription of rRNAs

b) Transcription of mRNAs

c) Transcription of tRNAs

d) Transcription of hnRNA

Answer: c


79. What is the name of the process where the introns are removed and the exons are joined together in a defined order?

a) Trailing

b) Capping

c) Tailing

d) Splicing

Answer: d


80. Which of the following types of RNA undergoes an additional process of capping and tailing during transcription?

a) sRNA

b) hnRNA

c) 5srRNA

d) snRNA

Answer: b


81. Which of the following is the unusual nucleotide that is added to the 5’-end of the hnRNA during capping?

a) Methyl Guanosine Triphosphate

b) Adenine

c) Guanine

d) Adenosine Triphosphate

Answer: a


82. What is the approximate count of the total number of adenylate residues that are added to the 3’-end of the hnRNA during the process of tailing?

a) 100-200

b) 200-300

c) 300-400

d) 500-700

Answer: b


83. Which of the following process represents the domination of the RNA-world?

a) Splicing

b) Trailing

c) Tailing

d) Capping

Answer: a

Genetic Code MCQ and Answers

84. Which of the following refers to a proposition which directs the sequence of amino acids during protein synthesis?

a) DNA fingerprinting

b) Genetic Code

c) Transcription

d) Endolysis

Answer: b


85. How many bases are required for coding 20 amino acids?

a) 1

b) 2

c) 3

d) 4

Answer: d


86. How many codons code for an amino acid?

a) 3

b) 8

c) 90

d) 61

Answer: d


87. When is a codon said to be unambiguous?

a) When it codes for 2 amino acids

b) When it codes for 1 amino acids

c) When it codes for 3 amino acids

d) When it codes for 4 amino acids

Answer: b

tRNA-Adapter Molecule MCQ and Answers

88. Who came up with the idea of “adapter molecule”?

a) James Watson

b) Francis Crick

c) Gregor Mendel

d) Charles Darwin

Answer: b


89. Which of the following is an adapter molecule?

a) mRNA

b) rRNA

c) cRNA

d) tRNA

Answer: d


90. What does the anticodon loop of the tRNA contain?

a) A site for binding the amino acids

b) Bases that are complementary to the code

c) They have UAA codons

d) They have UAG codons

Answer: b

Translation MCQ and Answers

91. What is the process of polymerisation of polypeptides to amino acids known as?

a) Transcription

b) Translation

c) Reverse transcription

d) Reverse translation

Answer: b


92. What is the process of activation of amino acids in the presence of ATP and its linkage to their cognate tRNA known as?

a) Charging of tRNA

b) Charging of ATP

c) Aminoacetylation of tRNA

d) Aminoacetylation of ATP

Answer: a


93. Which of the following cell organelle is responsible for the synthesis of proteins?

a) Lysosomes

b) Mitochondria

c) Nucleus

d) Ribosomes

Answer: d


94. How many types of proteins are present inside a single ribosome?

a) 40

b) 60

c) 80

d) 100

Answer: c


95. What happens when the small subunit of the ribosome encounters an mRNA?

a) Separation of the small and the larger subunit of the ribosome

b) Translation of the central dogma of DNA

c) Joining of the small and the larger subunit of the ribosome

d) Transcription of the central dogma of DNA

Answer: b


96. Which of the following is the start codon?

a) UAA

b) UAG

c) AUG

d) UGA

Answer: c


97. Where are the untranslated regions (UTRs) present?

a) At both the 5’ and the 3’ ends

b) At only the 5’ end

c) At only the 3’ end

d) Outer to the 5’ and the 3’ end

Answer: a

Regulation of Gene Expression MCQ and Answers

98. In which of the following levels can gene expression not be exerted?

a) Transitional level

b) Transcriptional level

c) Reverse transcriptional level

d) Processing level

Answer: c


99. Regulatory protein can act both as an activator and a repressor.

a) True

b) False

Answer: a

Lac Operon MCQ and Answers

100. Which polycistronic structural gene is regulated by a common promoter and regulatory gene?

a) Trp operon

b) Lac operon

c) Ara operon

d) His operon

Answer: b


101. How many structural genes are present in a lac operon?

a) One

b) Five

c) Three

d) Seven

Answer: c


102. What does the structural gene (y) of a lac operon code for?

a) β-galactosidase

b) Transacetylase

c) Permease

d) Glucagon

Answer: c


103. Which of the following is responsible for the switching on and off of the lac operon?

a) Lactose

b) Ethanol

c) Malate

d) Fructose

Answer: a


104. Which of the following is the necessary condition for the entry of lactose into the cell?

a) High level expression of lac operon

b) Low level expression of lac operon

c) Absence of lac operon in the cell

d) Absence of proteins in the cell

Answer: b


105. What is the regulation of a lac operon by a repressor known as?

a) Neutral regulation

b) Positive regulation

c) Mixed regulation

d) Negative regulation

Answer: d

Methodologies of HGP MCQ and Answers

106. Which of the following methodology is used to identify all the genes that are expressed as RNA in Human Genome Project (HGP)?

a) Sequence Annotation

b) Expressed Sequence Tags

c) Karyotyping

d) Ammonification

Answer: b


107. Which of the following is a suitable host for the process of cloning in Human Genome Project (HGP)?

a) Virus

b) All types of fungi

c) Bacteria

d) Protozoan

Answer: c


108. Which of the following is a suitable vector for the process of cloning in Human Genome Project (HGP)?

a) PAC (Protozoal Artificial Chromosomes)

b) FAC (Fungal Artificial Chromosomes)

c) VAC (Viral Artificial Chromosomes)

d) YAC (Yeast Artificial Chromosomes)

Answer: d


109. Based on whose principle were the DNA molecules fragmented in the year 1977?

a) Maurice Wilkins

b) Rosalind Franklin

c) James Watson

d) Frederick Sanger

Answer: d


110. How are the genetic and the physical maps assigned on the genome?

a) Based on microsatellites

b) Based on macrosatellites

c) Based on kinetochores

d) Based on centromeres

Answer: a

Salient Features of HGP MCQ and Answers

101. How many nucleotides are present in the human genome?

a) 3164.7 million

b) 2015.9 million

c) 1982.0 million

d) 3247.9 million

Answer: a


102. Repeated sequence makes a large portion of the human genome.

a) True

b) False

Answer: a

DNA Fingerprinting MCQ and Answers

103. What are the differences in the specific regions of DNA sequence called during DNA finger printing?

a) Non repetitive DNA

b) Repetitive DNA

c) Satellite DNA

d) Histone DNA

Answer: b


104. What are the small peaks achieved by the repetitive DNA during the density gradient centrifugation process of DNA finger printing known as?

a) Non repetitive DNA

b) Trough

c) Satellite DNA

d) Histone DNA

Answer: c


105. How DNA can be as a useful tool in the forensic applications?

a) Showing the same degree of polymorphism with hair follicles

b) Showing different degrees of polymorphism with saliva

c) By not possessing any hereditable information

d) By the presence of lysozymes in it

Answer: a


106. How does polymorphism arise?

a) Mutations

b) Recombination

c) Diploidy

d) Haploidy

Answer: a


FAQs on Molecular Basis of Inheritance

Q: How are genes passed down from parent to child?

A: Genes are passed down from parent to child through DNA. DNA is the molecule that contains the genetic information of an organism. Every cell in the body contains DNA, and this DNA is passed down from generation to generation.

Q: How does DNA determine the traits of an organism?

A: DNA determines the traits of an organism by specifying the sequence of amino acids in proteins. Proteins are the molecules that carry out the functions of the cell. The sequence of amino acids in a protein is determined by the sequence of nucleotides in the DNA.

Q: How do mutations occur?

A: Mutations are changes in the DNA sequence. These changes can be caused by things like mistakes during cell division, exposure to radiation, or chemicals. Mutations can be harmful, neutral, or beneficial.

Q: What is genetic recombination?

A: Genetic recombination is the process by which different versions of a gene are shuffled between generations. This process can create new combinations of genes, which can lead to new traits.

Q: What is genetic drift?

A: Genetic drift is the random change in the frequency of a gene in a population. This can happen when a small group of individuals breaks off from a larger group and starts a new population.

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