NEET MCQs on Gene Expression And Gene Regulation

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NEET Biology Gene Expression Multiple Choice Questions

Question 1. Co-repressor is a:

  1. Protein
  2. Metabolite
  3. Hormone
  4. Enzyme.

Answer: 2. Metabolite

Question 2. Reverse transcription was discovered by :

  1. Watson and Crick
  2. Porter
  3. Wilkins
  4. Temin.

Answer: 4. Temin.

Question 3. In the operon concept, the regulator gene regulates chemical reactions in the cell by :

  1. Inhibiting transcription of mRNA
  2. Inactivating enzymes in the reaction
  3. Inhibiting the substrate in the reactions
  4. Inhibiting the migration of tn-RNA in cytoplasm.

Answer: 1. Inhibiting transcription of mRNA

Gene Expression MCQs For NEET

Question 4. Which of the following statements is incorrect?

  1. Genetic code is ambiguous.
  2. Genetic code is degenerate.
  3. Genetic code is universal.
  4. Genetic code is non-overlapping.

Answer: 2. Genetic code is degenerate.

Read and Learn More NEET Biology Multiple Choice Question and Answers

Question 5. In E. coli according to the operon concept, an operator gene combines with:

  1. Inducer gene to switch on
  2. Regulator protein to “switch on” structural gene transcription
  3. Regulator gene to “switch off’ structural gene transcription
  4. Regulator protein to switch off structural gene transcription.

Answer: 3. Regulator gene to “switch off’ structural gene transcription

Question 6. Exons and introns arc parts of :

  1. DNA
  2. RNA
  3. mRNA
  4. Circular DNA.

Answer: 1. DNA

Question 7. Eukaryotes have :

  1. One promoter in gene structure
  2. Two promoters in gene structure
  3. No promoter gene
  4. Many promoters in gene structure.

Answer: 3. No promoter gene

Question 8. In Rous sarcoma virus:

  1. DNA → RNA→ Protein
  2. RNA → DNA → Protein
  3. RNA →DNA → RNA→ Protein
  4. DNA → RNA → RNA → Proleins.

Answer: 4. DNA → RNA → RNA → Proleins

Gene Expression MCQs For NEET

Question 9. Presence of F factor in bacteria :

  1. Indicates it as male
  2. Female
  3. Fast factor
  4. Free factor

Answer: 1. Indicates it as male

Question 10. The viral genes are expressed by :

  1. Lytic processes
  2. Lysogenic
  3. Both 1 and 2
  4. None of the above.

Answer: 3. Both 1 and 2

Question 11. Which of the following is not a carcinogen?

  1. X-rays
  2. Virus
  3. HNO2
  4. Starch.

Answer: 4. Starch

Question 12. According to the operon concept, the regulator gene forms.

  1. An inducer
  2. A repressor
  3. A small peptide
  4. A general inhibitor,

Answer: 2. A repressor

Gene Expression MCQs For NEET

Question 13. Which virus has a double-stranded RNA?

  1. Rheovirus
  2. Φ×174
  3. T2 phage
  4. TMV

Answer: 1. Rheovirus

Question 14. In the lysogenic cycle, the virus is:

  1. Virulent
  2. Temperate
  3. Harmless to the host cell
  4. Reproduces slowly.

Answer: 2. Temperate

Question 15. In bacteria, the exchange of genetic material between two different cells is brought by the process of:

  1. Transformation
  2. Transduction
  3. Conjugation
  4. All of the above

Answer: 4. All of the above

Gene Expression MCQs For NEET

Question 16. Phage host represents :

  1. Virion protein coat
  2. Virion nucleic acid
  3. Virion protein and nucleic acid
  4. None of the above.

Answer: 1. Virion protein coat

Question 17. The regulated unit of genetic material is called :

  1. Operator gene
  2. Regulator
  3. Operon
  4. Promoter gene.

Answer: 3. Operon

Question 18. A retrovirus is:

  1. TMV
  2. HIV
  3. Papillomavirus
  4. Both 2 and 3

Answer: 2. HIV

NEET Biology Gene Regulation Questions

Question 19. Bacteriophages are :

  1. Modified bacteria
  2. Primitive bacteria
  3. Viruses infecting bacteria
  4. Viruses infecting cyanobacteria.

Answer: 3. Viruses infecting bacteria

Question 20. Provirus differs from prophage about:

  1. Integration of RNA with host DNA
  2. Integration of genetic DNA with host DNA
  3. Integration of copy DNA of retrovirus with host DNA
  4. None of above

Answer: 3. Integration of copy DNA of retrovirus with host DNA

Question 21. Which virus has a rod-shaped structure 7

  1. Rlieo viruses
  2. Φ×174
  3. T phage
  4. TMV.

Answer: 4. TMV

Question 22. Tryptophan Operon is:

  1. Repressible system
  2. Inducible
  3. Controlled by regulator gene
  4. Made of 3 structural genes.

Answer: 1. Repressible system

Question 23. The presence of F-Factor in bacteria helps as :

  1. Fertility factor
  2. Female
  3. Fast factor
  4. Free factor.

Answer: 1. Fertility factor

Question 24. Exons and Introns are parts of;

  1. DNA
  2. mRNA
  3. RNA
  4. None of the above

Answer: 1. DNA

NEET Biology Gene Regulation Questions

Question 25. Eukaryotes have:

  1. One glue per cell
  2. Ten genes per cell
  3. Hundred genes per cell
  4. Thousand genes per cell.

Answer: 4. Thousand genes per cell.

Question 26. Oncogenic viruses are harmful in :

  1. Provirus stage
  2. Lytic phase
  3. Prophage stage
  4. Hybrid stage,

Answer: 1. Provirus stage

Question 27. Which of the following viruses have been extensively used to fuse cells in tissue culture :

  1. Sendai virus
  2. T2 viruses
  3. Phage lambda
  4. TMV,

Answer: 1. Sendai virus

Operon Model MCQs For NEET

Question 28. Jumping genes in maize were discovered by :

  1. H.G. Khorana
  2. Beadle
  3. Barbara McClintock
  4. Jacob.

Answer: 3. Barbara McClintock

Gene Regulation Recommended MCQs  Question 29. Thalassemia is an example of:

  1. Mutation
  2. Silent mutation
  3. Frameshift mutation
  4. Genetic disorders.

Answer: 3. Frameshift mutation

Question 30. Who found the occurrence of sexuality in bacteria ‘!

  1. Lederberg and Tatum
  2. Beadle and Tatum
  3. Sutton and Boveri
  4. Briggs and Kings.

Answer: 1. Lederberg and Tatum

Question 31. Operon consists of the following :

  1. Regulator and repressor
  2. Regulator, structural, and operator
  3. Regulator, structural, operator, and promoter
  4. Regulator and operator.

Answer: 3. Regulator, structural, operator, and promoter

Operon Model MCQs For NEET

Question 32. Restriction enzymes are used in genetic engineering because :

  1. They can cut DNA at specific base sequences.
  2. They are proteolytic enzymes which can degrade harmful proteins.
  3. They are nucleases that cut DNA at various sites
  4. They can join different DNA fragments.

Answer: 1. They can cut DNA at specific base sequence

Question 33. Wild-type E.cali cells are growing in a normal medium with glucose. They are transferred to a medium containing only lactose as the sugar. Which one of the following changes takes place?

  1. The lac operon is repressed
  2. All operons are induced
  3. E.coli cells stop dividing
  4. The lac operon is induced.

Answer: 4. The lac operon is induced

Question 34. An environmental agent that triggers transcription from an operon is a :

  1. Derepressor
  2. Inducer.
  3. Regulator
  4. Controlling element.

Answer: 2. Inducer

Question 35. The lac operon is an example of:

  1. Arabinose operon
  2. Inducible operon
  3. Repressive operon
  4. Overlapping genes,

Answer: 2. Inducible operon

NEET Previous Year Questions On Gene Regulation

Question 36. In split genes, the coding sequences are called :

  1. Cistrons
  2. Operons
  3. Exons
  4. Introns.

Answer: 3. Exons

Question 37. In the case of cyanobacteria :

  1. DNA → RNA → Protein
  2. RNA → DNA → Protein
  3. RNA → DNA → RNA → Protcin
  4. DNA → RNAH → RNA → Proteins.

Answer: 1. DNA → RNA → Protein

Question 38. A retrovirus is :

  1. TMV
  2. HIV
  3. Rheo virus
  4. Both 2 and 3

Answer: 4. Both 2 and 3

NEET Previous Year Questions On Gene Regulation

Question 39. The sequence of structural genes of Lac operon is :

  1. Lac Z, Lac Y, Lac A
  2. Lac Y, Lac Z, Lac A
  3. Lac A, Lac Z, Lac Y
  4. Lac A, Lac Y, Lac Z.

Answer: 1. Lac Z, Lac Y, Lac A

Question 40. Which virus has a single-stranded DNA :

  1. Rhevirus
  2. Φ×174 virus
  3. T2 phage
  4. TMV.

Answer: 2. Φ×174 virus

Question 41. In the lytic cycle, the virus is :

  1. Virulent
  2. Temperate
  3. Harmless to the host cell
  4. Reproduces slowly.

Answer: 1. Virulent

Lac Operon MCQs For NEET

Question 42. Resistance to antibiotics is a genetic trait that spreads naturally from one type of bacterium to :

  1. Another bacterium of the same strain
  2. Enkaryolic cells of all types
  3. Almost any other type of bacterium
  4. Any other cell containing copy DNA.

Answer: 3. Almost any other type of bacterium

Gene Regulation in Eukaryotes NEET Questions Question 43. Reverse transcriptase is :

  1. RNA-dependent DNA polymerase
  2. RNA-dependent RNA polymerase
  3. DNA-dependent RNA polymerase
  4. DNA-dependent DNA polymerase

Answer: 2. RNA-dependent RNA polymerase

Question 44. Transduction in bacteria is mediated by :

  1. Cosmids
  2. Phage vectors
  3. Plasmid vectors
  4. F-factors.

Answer: 2. Phage vectors

Question 45. The nuclease enzyme which begins its attack from a free end of a polynucleotide :

  1. Endonuclease
  2. Kinase
  3. Exonuclease
  4. Polymerase.

Answer: 3. Exonuclease

Question 46. Normally, the DNA molecule has A-T, and G-C pairing. However, these bases can exist in alternative, valency consistent status, owing to rearrangement called :

  1. Tautomerization
  2. Base analogue
  3. Frameshift mutation
  4. Point mutation

Answer: 3. Frameshift mutation

Lac Operon MCQs For NEET

Question 47. The fertility factor or F+ factor that plays a key role in conjugation is a:

  1. Retrovirus
  2. Plasmid
  3. Viroid
  4. Lysogenic phage

Answer: 2. Plasmid

Question 48. When DNA is exchanged between two bacteria via cytoplasmic bridges, the process is called :

  1. Transformation
  2. General transduction
  3. Restricted transduction
  4. Conjugation.

Answer: 4. Conjugation

Question 49. When a bacteriophage, in its lytic phage, carries some of the bacterium’s partially digested chromosome with it to another host cell, the process is called :

  1. Transformation
  2. General transduction
  3. Restricted transduction
  4. Conjugation

Answer: 2. General transduction

Question 50. In general, bacterial genes are regulated at the time of:

  1. Transcription
  2. Translation
  3. Post translation
  4. Post transcription.

Answer: 1. Transcription

Lac Operon MCQs For NEET

Question 51. The activity of a repressor depends on whether :

  1. The repressor is positioned next to the operon
  2. The repressor is positioned next to the promoter
  3. A key substance in the metabolic pathway is present
  4. There is enough RNA polymerase present.

Answer: 2. The repressor is positioned next to the promoter

Question 52. In gene therapy, DNA is inserted in a cell to compensate for :

  1. The absence of plasmid
  2. Mutant alleles
  3. Holes in the DNA made by viruses
  4. The lack of copy DNA.

Answer: 2. Mutant alleles

Question 53. In the lac operon structural gene ‘Z’ is responsible for the synthesis of the enzyme :

  1. β-galactosidase
  2. Galactosidase permease
  3. Galactosidase transacetylase.

Answer: 1. β-galactosidase

Gene Regulation in Eukaryotes NEET Questions Question 54. In the genetic code dictionary, how many codons are used to code for all the 20 amino acids?

  1. 64
  2. 61
  3. 60
  4. 20.

Answer: 2. 61

Question 55. Replication of DNA occurs during the S-phase of interphase Okazaki fragments are joined in a correct sequence by:

  1. DNA polymerase I
  2. DNA ligase
  3. Primase and helicase
  4. RNA polymerase.

Answer: 2. DNA ligase

Question 56. Which of the following makes use of RNA as a template to synthesize DNA?

  1. DNA polymerase
  2. RNA polymerase
  3. Reverse transcriptase
  4. DNA-dependent RNA polymerase.

Answer: 3. Reverse transcriptase

Lac Operon MCQs For NEET

Question 57. Which one of the following triplet codes is correctly matched with its specificity for an amino acid in protein synthesis or as a start or stop signal?

  1. UUU – Stop
  2. UGU Lencino
  3. UAC – Tyrosine
  4. UCG – Start.

Answer: 2. UGU Lencino

Question 58. How many genes are present on chromosomes Y and A respectively :

  1. 2869,231
  2. 232, 2968
  3. 231,2968
  4. 2968,231.

Answer: 3. 231,2968

Question 59. UTR is present on :

  1. MRNA at one end
  2. 3′ end of tRNA
  3. 5′ and 3′ end of mRNP
  4. 3′ end 5′ end of tRNA.

Answer: 3. 5′ and 3′ end of mRNP

Question 60. Which of the following is a ‘dual function’?

  1. AUG
  2. UUU
  3. GUA
  4. CCC.

Answer: 1. AUG

Question 61. The base sequence for a nucleic acid segment is given as GAG AGG GGA CCA. From this it can be concluded that it is a segment of:

  1. DNA strand
  2. mRNA
  3. t-RNA strand
  4. Data is not sufficient.

Answer: 4. Data not sufficient

Question 62. Which of the following does not follow the central dogma of molecular biology?

  1. mUcor
  2. Chlamydomonas
  3. HIV
  4. Mycobacterium.

Answer: 3. HIV

Question 63. The largest gene in humans is

  1. Oncogene
  2. Tumor suppress gene
  3. Dystrophin
  4. Insulin.

Answer: 3. Dystrophin

Question 64. In a DNA molecule, adenine is 15% what would be % the age of Guanine?

  1. 15%
  2. 30%
  3. 35%
  4. 85%.

Answer: 3. 35%

Question 65. The length of DNA with 23 base pairs is :

  1. 78.4 A°
  2. 78.2
  3. 78 A°
  4. 74.8A°

Answer: 2. 78.2

Transcription And Translation NEET MCQs

Question 66. Which of the following have ds RNA?

  1. TMV
  2. Ribozyme
  3. SnRNA
  4. Rheovirus.

Answer: 4. Rheovirus

Question 67. Regulation of lac operon by repressor is referred to as :

  1. +ve regulation
  2. – ve regular
  3. Repressible
  4. Anabolic.

Answer: 2. – ve regular

Question 68. The accessibility of the promoter region of prokaryotic DNA is many cases regulated by the interaction of proteins with a sequence termed operator. The operator region is adjacent to :

  1. Structural gene
  2. Regulator gene
  3. Promoter element
  4. Gene ‘a’.

Answer: 3. Promoter element

Question 69. At the time of organogenesis, genes regulate the process at different levels and a different times due to the:

  1. Promoter
  2. Regulator
  3. Intron
  4. Exon.

Answer: 4. Exon

Question 70. In Negative operon :

  1. Co-repressor binds with repressor
  2. Co-repressor does not bind with the repressor
  3. Corepressor binds with inducer.
  4. cAMP hurts lac operon

Answer: 1. Co-repressor binds with repressor

Question 71. Restriction enzymes:

  1. Are endonucleases that cleave DNA at specific sites
  2. Make DNA complementary to an existing DNA or RNA
  3. Cut or join DNA fragments
  4. Are required in vectorless direct gene transfer.

Answer: 1. Are endonucleases which cleave DNA at specific sites

Question 72. The process of introduction of foreign genes for improving genotype is called :

  1. Tissue culture
  2. Vernalization
  3. Genetic engineering
  4. Eugenics.

Answer: 4. Eugenics

Transcription And Translation NEET MCQs

Question 73. The diagram shows an important concept in the genetic implication of DNA. Fill in the blanks A to C.

Gene Expression And Gene Regulation Genetic Implication Of DNA

  1. A – translation B – transcription C – Erevin Chargaff
  2. A – transcription B – translation C – Francis Crick
  3. A – translation B – extension C – Rosalind Franklin
  4. A – transcription B – replication C – James Watson

Answer: 2. A – transcription B – translation C – Francis Crick

Question 74. Which one of the following conditions though harmful in itself, is also a potential saviour from all mosquito-borne infectious diseases?

  1. Pernicious anemia
  2. Leukaemia
  3. Thalassaemia
  4. Sickle cell anemia.

Answer: 4. Sickle cell anemia

Question 75. In E. coli, during lactose metabolism repressor binds to :

  1. Regulator gene
  2. Promoter gene
  3. Operator gene
  4. Structural gene.

Answer: 2. Promoter gene

MCQs on Regulation Of Gene Expression In Eukaryotes Question 76. The genes are responsible for the growth and differentiation of living organisms through the regulation of :

  1. Translation
  2. Transcription
  3. Transduction
  4. Both 1 and 2

Answer: 3. Transduction

Question 77. Which of the following is specifically used in genetic engineering?

  1. Ligase
  2. Gyrase
  3. Restriction endonuclease
  4. DNA polymerase.

Answer: 3. Restriction endonuclease

Question 78. Restriction endonucleases :

  1. Are present in mammalian cells for degradation of DNA when the cell dies
  2. Are used in genetic engineering for ligating two DNA molecules
  3. Are used for in vitro DNA synthesis
  4. Are synthesized by bacteria as part of their defense

Answer: 4. Are synthesized by bacteria as part of their defense

Transcription And Translation NEET MCQs

Question 79. Cancer cells are more easily damaged by radiation than normal cells because they are :

  1. Starved of mutation
  2. Undergoing rapid division
  3. Different in structure
  4. Non-dividing.

Answer: 2. Undergoing rapid division

Question 80. DNA fingerprinting refers to :

  1. Molecular analysis of profiles of DNA samples
  2. Analysis of DNA sample using imprinting device
  3. Techniques used for molecular analysis of different specimens of DNA
  4. Techniques used for identification of fingerprints of

Answer: 4. Techniques used for the identification of fingerprints of

Question 81. What kind of evidence suggested that man is more closely related to chimpanzees than to other hominoid apes?

  1. Evidence from DNA from sex chromosomes only
  2. Comparison of chromosomal morphology only
  3. Evidence from fossil remains and the fossil mitochondrial DNA alone
  4. Evidence from DNA extracted from sex chromosomes, autosomes, and mitochondria.

Answer: 4. Evidence from DNA extracted from sex chromosomes, autosomes, and mitochondria

Question 82. In transgenics, expression of transgene in target tissue is determined by :

  1. Enhancer
  2. Promoter
  3. Transgene
  4. Reporter.

Answer: 4. Reporter

MCQs on Regulation Of Gene Expression In Eukaryotes Question 83. The Ti plasmid is often used for making transgenic plants. This plasmid is found in :

  1. Azotobacter
  2. Rhizobium of the roots of leguminous plants
  3. Agrobacterium
  4. yeast as a 2μm plasmid.

Answer: 3. Agrobacterium

Gene Expression MCQs For NEET

Question 84. Which enzyme/s will be produced in a cell in which there is a nonsense mutation in the lac Y gene?

  1. Lactose permease
  2. Transacetylase
  3. Lactose permease and transacetylase
  4. β-galactosidase.

Answer: 4. β-galactosidase.

Question 85. Supercoiled DNA can be traced in :

  1. Prokaryotes and eukaryotes
  2. Eukaryotes only
  3. Prokaryotes only
  4. None of these

Answer: 1. Prokaryotes and eukaryotes

Question 86. Phosphorus is present in :

  1. Protein
  2. DNA
  3. RNA
  4. Both DNA and RNA.

Answer: 4. Both DNA and RNA

Question 87. In a given DNA segment ATG, ACC, AGG, ACC, CCA, ACA, the first base gets mutated. The effect of this on coding by this DNA segment will result in :

  1. A complete change in the type as well as a sequence of amino acids
  2. Change in the first amino acid only
  3. One amino acid less in the protein
  4. No change in the sequence
  5. No coding.

Answer: 2. One amino acid less in the protein

Question 88. Okazaki fragments are joined in a correct sequence by :

  1. DNA polymerase I
  2. DNA ligase
  3. RNA polymerase
  4. Primase
  5. Heliease.

Answer: 2. DNA ligase

Gene Expression MCQs For NEET

Question 89. In the lac operon, the structural genes are switched off when :

  1. The repressor binds to the operator
  2. Repressor binds to the promoter
  3. The repressor binds to the regulator
  4. Repressor binds to the inducer
  5. The repressor binds to the allolactose.

Answer: 1. The repressor binds to the operator

Question 90. In the lac operon structural gene V is responsible for the synthesis of the enzyme :

  1. β-galactosidase
  2. Galactosidase permease
  3. Galactosidase transacetylase
  4. None of these.

Answer: 1. β-galactosidase

Question 91. When lactose is added to the culture of E.coli, a few of its molecules get into the cells with the help of:

  1. Galactosidase
  2. Permease
  3. Lactase
  4. Transacetylase.

Answer: 2. Permease

Gene Regulation Recommended MCQs Question 92. During transcription, holoenzyme RNA polymerase binds to a DNA sequence and the DNA assumes a saddle Ike structure at that point. What is that sequence called?

  1. TATA box
  2. AAAT box
  3. GGTT box
  4. CAAT box

Answer: 1. TATA box

NEET Biology Gene Regulation Questions

Question 93. In the lac operon model, lactose molecules function a is :

  1. Inducers that bind with the operator gene
  2. Repressors that bind with the operator gene
  3. Inducers that bind with the repressor protein
  4. Compressors that bind with repressor protein.

Answer: 3. Inducers that bind with the repressor protein

Question 94. Protein synthesis in an animal cell occurs :

  1. Only on the ribosomes present in the cytosol
  2. Only on ribosomes attached to the nuclear envelope and endoplasmic reticulum
  3. On ribosomes present in the nucleolus as well as in the cytoplasm
  4. No ribosomes are present in the cytoplasm as well as in mitochondria.

Answer: 4. No ribosomes present in the cytoplasm as well as in mitochondria

Question 95. E.coli cells with a mutated z gene of the lac operon cannot grow in a medium containing only lactose as the source of energy because :

  1. In the presence of glucose, E.coli cells do not utilize lactose
  2. They cannot transport lactose from the medium into the cell
  3. The lac operon is constitutively active in these cells
  4. They cannot synthesize functional beta-galactosidase.

Answer: 4. They cannot synthesize functional beta-galactosidase

Question 96. Which one of the following makes use of RNA as a template to synthesize DNA?

  1. Reverse transcriptase
  2. DNA dependant RNA polymerase
  3. DNA polymerase
  4. RNA polymerase.

Answer: 1. Reverse transcriptase

Question 97. Differentiation of organs and tissues in a developing organism is associated with:

  1. Differential expression of genes
  2. Lethal mutations
  3. Deletion of genes
  4. Developmental mutations.

Answer: 1. Differential expression of genes

NEET Biology Gene Regulation Questions

Question 98. Intron transcripts in heterogenous nuclear RNA (hn- RNA) are removed and exon transcripts are joined together under the direction of protein complexes. These complexes are :

  1. Polysomes
  2. Cdk complex
  3. Spliceosomes
  4. Endopeptidases.

Answer: 3. Spliceosomes

Question 99. In regulation of gene expression in prokaryotes :

  1. Lactose acts as the suppressor for gene expression
  2. Tryptophan acts as the inducer of gene expression
  3. The regulator gene is the one that produces the repressor molecule
  1. 1 alone correct
  2. alone correct
  3. 3 alone correct
  4. 2 and 3 are correct.

Answer: 3. 3 alone correct

Question 100. The sequence of structural genes in the lac operon concept is :

  1. Lac A, lac Z, lac Y
  2. Lac A, lac Y, lac Z
  3. Lac Y, lac Z, lac A
  4. Lac Z, lac Y, lac A.

Answer: 4. Lac Z, lac Y, lac A.

NEET Biology Gene Regulation Questions

Question 101. All genes located on the same chromosome :

  1. Form different groups depending on their relative distance
  2. Form one linkage group
  3. Will not form any linkage groups.
  4. Form interactive groups that affect the phenotype

Answer: 2. Will not form any linkage groups.

Question 102. Conditions of a karyotype 2 n+1 and 2n ± 2 are called:

  1. Aneuploidy
  2. Polyploidy
  3. Allopolyploidy
  4. Monosomy.

Answer: 1. Aneuploidy

Question 103. Distance between the genes and advantage of recombination shows :

  1. A direct relationship
  2. An inverse relationship
  3. A parallel relationship
  4. No relationship.

Answer: 2. An inverse relationship

Question 104. If genetic disease is transferred from a phenotypically normal but carrier female to only some of the male progeny, the disease is :

  1. Autosomal dominant
  2. Autosomal recessive
  3. Sex-linked dominant
  4. Sex-linked recessive.

Answer: 4. Sex-linked recessive.

Operon Model MCQs For NEET

Question 105. In sickle cell anaemia glutamic acid is replaced by valine. Which one of the following triplets codes for valine?

  1. G G G
  2. A A G
  3. GAA
  4. GUG.

Answer: 4. GUG.

Question 106. A person having genotype IA IB would show the blood group as AB. This is because of:

  1. Pleiotropy
  2. Co-dominance
  3. Segregation
  4. Incomplete dominance.

Answer: 2. Co-dominance

Gene Regulation in Eukaryotes NEET Questions Question 107. ZZ / ZW type of sex determination is seen in :

  1. Platypus
  2. Snails
  3. Cockroach
  4. Peacock.

Answer: 4. Peacock.

Question 108. A cross between two tall plants resulted in offspring having few dwarf plants. What would be the genotypes of both the parents?

  1. TT and Tt
  2. Tt and Tt
  3. TT and TT
  4. Tt and tt.

Answer: 2. Tt and Tt

Question 109. In a dihybrid cross, if you get a 9:3:3:1 ratio it denotes that:

  1. The alleles of two genes interact with each other
  2. It is a multigenic inheritance
  3. It is a case of multiple alleles
  4. The alleles of two genes segregate independently.

Answer: 4. The alleles of two genes are segregating independently.

Operon Model MCQs For NEET

Question 110. Which of the following will not result in variations among siblings?

  1. Independent assessment of genes
  2. Crossing over
  3. Linkage
  4. Mutation.

Answer: 3. Linkage

Question 111. Mendel’s law of independent assortment holds good for genes situated on the :

  1. Non-homologous chromosomes
  2. Homologous chromosomes
  3. Extranuclear genetic element
  4. Same chromosome.

Answer: 1. Non-homologous chromosomes

Gene Regulation in Eukaryotes NEET Questions Question 112. Occasionally, a single gene may express more than one effect. The phenomenon is called :

  1. Multiple allelism
  2. Mosaicism
  3. Pleiotropy
  4. Polygeny.

Answer: 3. Pleiotropy

Question 113. In a certain taxon of insects, some have 1 7 chromosomes and the others have 18 chromosomes. The 17 and 18 chromosome-bearing organisms are :

  1. Males and females, respectively
  2. Females and males, respectively
  3. All males
  4. All females.

Answer: 1. Males and females, respectively

Question 114. The inheritance pattern of a gene over generations among humans is studied by the pedigree analysis. The character studied in the pedigree analysis is equivalent to :

  1. Quantitative trait
  2. Mendelian trait
  3. Polygenic trait
  4. Maternal trait.

Answer: 2. Mendelian trait

Question 115. It is said that Mendel proposed that the factor controlling any character is discrete and independent. This proposition was based on the :

  1. Results of F3 generation of a cross.
  2. Observations that the offspring of a cross made between the plants having two contrasting characters show only one character without any blending.
  3. Self-pollination of F1 offspring
  4. Cross-pollination of parental generations.

Answer: 2. Observations that the offspring of a cross made between the plants having two contrasting characters show only one character without any blending.

Question 116. Two genes ‘A’ and ‘B’ are linked. In a dihybrid cross involving these two genes, the F1 heterozygote is crossed with the homozygous recessive parental type (aa bb). What would be the ratio of offspring in the next generation?

  1. 1 : 1: 1: 1
  2. 9 : 3 : 3: 1
  3. 3:1
  4. 1: 1.

Answer: 1. 1: 1 : 1: 1

Operon Model MCQs For NEET

Question 117. In the F2 generation of a Mendelian dihybrid cross the number of phenotypes and genotypes are :

  1. Phenotypes – 4; genotypes – 16
  2. Phenotypes – 9; genotypes – 4
  3. Phenotypes – 4; genotypes – 8
  4. Phenotypes – 4; genotypes – 9

Answer: 4. Phenotypes – 4; genotypes – 9

Regulation of Gene Expression in Eukaryotes MCQ Question 118. The mother and father of a person with the ‘O’ blood group have ‘A’ and ‘B’ blood groups respectively. What would be the genotype of both mother and father?

  1. The mother is homozygous for the ‘A’ blood group and the father is heterozygous for ‘B’.
  2. Mother is heterozygous for ‘A’ blood group and father is homozygous for ‘B’
  3. Both mother and father are heterozygous for the ‘A’ and ‘B’ blood groups, respectively
  4. Both mother and father are homozygous for the ‘A’ and ‘B’ blood groups, respectively.

Answer: 3. Both mother and father are heterozygous for the ‘A’ and ‘B’ blood groups, respectively

Question 119. In a DNA strand, the nucleotides are linked together by:

  1. Glycosidic bonds
  2. Phosphodiester bonds
  3. Peptide bonds
  4. Hydrogen bonds.

Answer: 2. Phosphodiester bonds

Question 120. A nucleoside differs from a nucleotide. It lacks the

  1. Base
  2. Sugar
  3. Phosphate group
  4. Hydroxyl group.

Answer: 3. Phosphate group

Question 121. Both deoxyribose and ribose belong to a class of sugars called :

  1. Trioses
  2. Hexoses
  3. Pentoses
  4. Polysaccharides.

Answer: 3. Pentoses

Question 122. The fact that a purine base is always paired through hydrogen bonds with a pyrimidine base leads to, in the DNA double helix :

  1. The antiparallel nature
  2. The semi-conservative nature
  3. Uniform width throughout DNA
  4. Uniform length in all DNA.

Answer: 3. Uniform width throughout DNA

Question 123. The net electric charge on DNA and histones is :

  1. Both positive
  2. Both negative
  3. Negative and positive, respectively
  4. Zero

Answer: 3. Negative and positive, respectively

Regulation of Gene Expression in Eukaryotes MCQ Question 124. The promoter site and the terminator site for transcription are located at :

  1. 3’ (downstream) end and 5’ (upstream) end, respectively of the transcription unit
  2. 5’ (upstream) end and 3’ (downstream) end, respectively of the transcription unit
  3. The 5’ (upstream) end
  4. The 3’ (downstream) end.

Answer: 2. 5’ (upstream) end and 3’ (downstream) end, respectively of the transcription unit

Question 125. Which of the following statements is the most appropriate for sickle cell anemia?

  1. It cannot be treated with iron supplements
  2. It is a molecular disease
  3. It confers resistance to acquiring malaria
  4. All of the above.

Answer: 4. All of the above

Question 126. One of the following is true concerning AUG

  1. It codes for methionine only
  2. It is also an initiation codon
  3. It codes for methionine in both prokaryotes and eukaryotes
  4. All of the above.

Answer: 4. All of the above

Question 127. The first genetic material could be :

  1. Protein
  2. Carbohydrates
  3. DNA
  4. RNA

Answer: 4. RNA

Question 128. About mature ntRNA in eukaryotes :

  1. Exons and introns do not appear in the mature RNA
  2. Exons appear but introns do not! appear in the mature RNA
  3. Introns appear but exons do not appear in the mature RNA
  4. Both exons and introns appear in the mature RNA.

Answer: 2. Exons appear but introns do not! appear in the mature RNA

Question 129. The human chromosomes with the highest and least number of genes in them are respectively :

  1. Chromosome 21 and Y
  2. Chromosome 1 and X
  3. Chromosome 1 and Y
  4. Chromosome X and Y.

Answer: 3. Chromosome 1 and Y

Question 130. Who amongst the following scientists had no contribution in the development of the double helix model for the structure of DNA?

  1. Rosalind Franklin
  2. Maurice Wilkins
  3. Erwin Chargaff
  4. Meselson and Stahl.

Answer: 4. Meselson and Stahl.

Question 131. DNA is a polymer of nucleotides that are linked to each other by a 3″-5’ phosphodiester bond. To prevent the polymerization of nucleotides, which of the following modifications would you choose?

  1. Replace purine with pyrimidines
  2. Remove/Replace 3″ OH group in deoxyribose
  3. Remove/Replacc 2’ OH group with some other group in deoxyribose
  4. Both ‘2’ and ‘3’.

Answer: 2. Remove/Replace 3″ OH group in deoxyribose

Question 132. Discontinuous synthesis of DNA occurs in one strand, because :

  1. DNA molecule being synthesized is very long
  2. DNA-dependent DNA polymerase catalyzes polymerization only in one direction (5’- 3’)
  3. It is a more efficient process
  4. DNA ligase has to have a role.

Answer: 2. DNA-dependent DNA polymerase catalyzes polymerization only in one direction (5’-3’)

Question 133. Which of the following steps in transcription is catalyzed by RNA polymerase?

  1. Initiation
  2. Elongation
  3. Termination
  4. All of the above.

Answer: 2. Elongation

Question 134. Control of gene expression takes place at the level of:

  1. DNA-replication
  2. Transcription
  3. Transition
  4. None of the above

Answer: 2. Transcription

NEET Previous Year Questions On Gene Regulation

Question 135. Regulatory proteins are the accessory proteins that interact with RNA polymerase and affect its role in transcription. Which of the following statements is correct about regulatory protein?

  1. They only increase expression
  2. They only decrease expression.
  3. They interact with RNA polymerase but do not affect the expression
  4. They can act both as activators and as repressors

Answer: 4. They can act both as activators and as repressors

Question 136. Which was the last human chromosome to be completely sequenced :

  1. Chromosome 1
  2. Chromosome 11
  3. Chromosome 21
  4. Chromosome X.

Answer: 1. Chromosome 1

Question 137. Which of the following are the functions of RNA?

  1. It is a carrier of genetic information from DNA to ribosomes synthesizing polypeptides
  2. It carries amino acids to ribosomes
  3. It is a constituent component of ribosomes
  4. All of the above.

Answer: 4. All of the above.

Question 138. While analyzing tire DNA of an organism a total number of 5386 nucleotides were found out of which the proportion of different bases was: Adenine = 29%, Guanine = 17%, Cytosine = 32%. Thymine = 17%. Considering Chargaffs rule it can be concluded that:

  1. It is a double-stranded circular DNA
  2. It is a single-stranded DNA
  3. It is a double-stranded linear DNA
  4. No conclusion can be drawn.

Answer: 2. It is single-stranded DNA

Question 139. In some viruses, DNA is synthesized by using RNA as a template. Such a DNA is called :

  1. A-DNA
  2. B-DNA
  3. cDNA
  4. DNA.

Answer: 3. cDNA

Question 140. IfMeselson and Stahl’s experiment is continued for four generations in bacteria, the ratio of 15N-/15N: 15N/14N/: 1 4N/ 14N containing DNA in the fourth generation would be :

  1. 1:1:0
  2. 1:4:0
  3. 0:l:3
  4. 0:1:7.

Answer: 4. 0:1:7

Question 141. If the sequence of nitrogen bases of the coding strand of DNA in a transcription unit is: 5’ – ATG A ATG-3’, the sequence of bases in its RNA transcript would be :

  1. 5’ – AUG A AUG-3’
  2. 5’-UACUUAC-3’
  3. 5’ – CAUUCAU-3’
  4. 5’ – G U A A G U A – 3’.

Answer: 1. 5’ – AUG A AUG-3’

Question 142. The RNA polymerase holoenzyme transcribes :

  1. The promoter, structural gene, and the terminator region
  2. The promoter, and the terminator
  3. The structural gene and the terminator regions
  4. The structural gene only.

Answer: 3. the structural gene and the terminator regions

Question 143. If the base sequence of a codon mmRNA is 5’-AUC- 3’, the sequence of tRNA pairing with it must be :

  1. 5’ – UAC – 3’
  2. 5’ – CAU – 3’
  3. 5’ -AUG -3’
  4. 5’ – GUA – 3’

Answer: 2. 5’ – CAU – 3’

Question 144. The amino acid attaches to the tRNA at its :

  1. 5’-end
  2. 3’-end
  3. Anti codon site
  4. DHU loop

Answer: 2. 3’-end

Question 145. To initiate translation, the mRNA first binds to :

  1. The smaller ribosomal sub-unit,
  2. The larger ribosomal sub-unit
  3. The whole ribosome
  4. No such specificity exists.

Answer: 1. The smaller ribosomal sub-unit,

Question 146. In E.coli, the lac operon gets switched on when :

  1. lactose is present and it binds to the repressor
  2. The repressor binds to the operator
  3. RNA polymerase binds to the operator
  4. Lactose is present and it binds to RNA polymerase.

Answer: 1. lactose is present and it binds to the repressor

Question 147. Which of the following statements are correct?

  1. RNA polymerase 1 transcribes rRNAs
  2. RNA polymerase 2 transcribes snRNAs
  3. RNA polymerase 3 transcribes hnRNA
  4. RNA polymerase 2 transcribes hnRNA.
  1. 1 and 2 correct
  2. 1 and 3 are correct
  3. 1, 2, and 4 are correct
  4. 2 and 3 are correct
  5. 1 and 4 are correct.

Answer: 5. 1 and 4 are correct.

Question 148. In Hershey and Chase experiments, radioactive 32P was used to culture bacteriophages which resulted in radioactive :

  1. ViralDNA
  2. Bacterial capsule
  3. Viral proteins
  4. Plasma membrane of bacteria.

Answer: 1. ViralDNA

Question 149. The inducer for switching ‘on’ the lac operon in bacteria is:

  1. Presence of lactose
  2. Number of bacteria
  3. Presence of structural genes in the bacteria
  4. Presence of sucrose
  5. Presence of RNA polymerase

Answer: 1. Presence of lactose

Question 150. Select the incorrect statement (s):

1. Six codons do not code for any amino acid.

2. Codon is read in mRNA in a continuous fashion

3. Three condoms function as stop codons

4. The initiator codon AUG codes for methionine.

  1. 1,2 and 4 are incorect
  2. 1, 2 and 3 are incorect
  3. 2, 3 and 4 are incorect
  4. 2 alone is correct
  5. 1 alone is incorrect.

Answer: 5. 1 alone is incorrect.

Question 151. The collection of cloned DNA segments obtained from the complete genome is called :

  1. DNA library
  2. Genomic bank
  3. Gene bank
  4. Both 2 and 3

Answer: 4. Both 2 and 3

NEET Previous Year Questions On Gene Regulation

Question 152. In the operon model, the regulator gene functions as :

  1. Regulator
  2. Inhibitor
  3. Repressor
  4. Stimulator.

Answer: 3. Repressor

Question 153. Genes involved in turning on and off of structural genes are:

  1. Operator genes
  2. Regulator genes
  3. Redundant genes
  4. Promoter genes.

Answer: 2. Regulator genes

Question 154. Lac operon is related to :

  1. Synthesis of enzymes for lactose catabolism
  2. Synthesis of enzymes for lactose anabolism
  3. Synthesis of lac by lac insects
  4. Degradation of lac by lac insects.

Answer: 1. Synthesis of enzymes for lactose catabolism

Question 155. According to the operon concept, the regulator gene regulates chemical reactions in the cell by :

  1. Inactivating enzyme in the reaction
  2. Inhibiting the substrate in the reaction
  3. Inhibiting transcription of m-RNA
  4. Inhibiting the migration of mRNA into the cytoplasm.

Answer: 3. Inhibiting transcription of m-RNA

Question 156. The modem concept of a gene is that it is :

  1. A segment of DNA
  2. A segment of chromosome
  3. A functional unit of DNA
  4. All of these

Answer: 3. A functional unit of DNA

Question 157. SV 40 has five genes but the type of proteins synthesized by it is more than twice the number of genes present in it. It shows the presence of:

  1. Contained genes
  2. Split genes
  3. Overlapping genes
  4. Degenerate genes.

Answer: 3. overlapping genes

Question 158. Provirus differs from prophage about:

  1. Integration of RNA with host DNA
  2. Integration of genetic DNA with host DNA
  3. Integration of copy DNA of retrovirus with host DNA
  4. None of the above.

Answer: 3. Integration of copy DNA of retrovirus with host DNA

Question 159. Which virus has a rod-shaped structure?

  1. Rheo viruses
  2. Φ× 174
  3. T phage
  4. TMV.

Answer: 4. TMV.

Question 160. Tryptophan Operon is :

  1. Repressible system
  2. Inducible
  3. Controlled by regulator gene
  4. Made of 3 structural genes.

Answer: 1. Repressible system

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