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Molecular Basis of Inheritance: Class-XII


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MCQs on Molecular Basis of Inheritance: Class-XII for NEET Practice


Match List-I with List-II.

List-I (Eukaryotic Polymerases)List-II (Transcripts)
A. RNA Polymerase II. tRNA, 5S rRNA, snRNA
B. RNA Polymerase IIII. 28S, 18S, and 5.8S rRNA
C. RNA Polymerase IIIIII. hnRNA (precursor mRNA)

[Molecular-Basis-of-Inheritance] [class-xii ]

  • A-II, B-III, C-I
  • A-I, B-II, C-III
  • A-II, B-I, C-III
  • A-III, B-II, C-I
  • Correct Option: A  [ A-II, B-III, C-I ]

    Remark: In eukaryotes, RNA Polymerase I transcribes large rRNAs (28S, 18S, 5.8S). RNA Polymerase II transcribes hnRNA (heterogeneous nuclear RNA), which processes into mRNA. RNA Polymerase III transcribes tRNA, 5S rRNA, and snRNAs. A mnemonic is RMT (I->rRNA, II->mRNA, III->tRNA).

Match List-I with List-II.

List-I (RNA Processing)List-II (Process)
A. CappingI. Removal of Introns
B. TailingII. Addition of 7-methylguanosine
C. SplicingIII. Addition of Adenylate residues
D. ExonsIV. Coding sequences joined together

[Molecular-Basis-of-Inheritance] [class-xii ]

  • A-II, B-III, C-I, D-IV
  • A-III, B-II, C-I, D-IV
  • A-II, B-I, C-III, D-IV
  • A-IV, B-III, C-I, D-II
  • Correct Option: A  [ A-II, B-III, C-I, D-IV ]

    Remark: Capping involves adding a 7-methylguanosine cap to the 5-prime end of hnRNA. Tailing involves adding a Poly-A tail (Adenylate residues) to the 3-prime end. Splicing is the removal of non-coding Introns. Exons are the coding sequences that are joined together to form the mature mRNA.

Match List-I with List-II.

List-I (Genetic Code)List-II (Feature)
A. DegenerateI. Code is contiguous (no punctuation)
B. UnambiguousII. Multiple codons for one amino acid
C. UniversalIII. One codon codes for only one amino acid
D. Comma-lessIV. Same code in bacteria and humans

[Molecular-Basis-of-Inheritance] [class-xii ]

  • A-II, B-III, C-IV, D-I
  • A-III, B-II, C-IV, D-I
  • A-II, B-I, C-IV, D-III
  • A-I, B-II, C-III, D-IV
  • Correct Option: A  [ A-II, B-III, C-IV, D-I ]

    Remark: Degenerate means that some amino acids are coded by more than one codon (redundancy). Unambiguous means a specific codon always codes for the same specific amino acid. Universal means the code applies to nearly all organisms. Comma-less means the code is read continuously without pauses or punctuation.

Match List-I with List-II.

List-I (tRNA Structure)List-II (Description)
A. Anticodon LoopI. Shape of 2D structure
B. Acceptor Arm (3-prime)II. Binds to mRNA codon
C. Clover-leafIII. Binds to Amino Acid
D. Inverted LIV. Shape of 3D structure

[Molecular-Basis-of-Inheritance] [class-xii ]

  • A-II, B-III, C-I, D-IV
  • A-III, B-II, C-I, D-IV
  • A-II, B-III, C-IV, D-I
  • A-I, B-IV, C-II, D-III
  • Correct Option: A  [ A-II, B-III, C-I, D-IV ]

    Remark: The Anticodon loop contains bases complementary to the mRNA codon. The 3-prime Acceptor Arm binds to the specific amino acid. The 2D secondary structure resembles a Clover-leaf. The actual 3D tertiary structure resembles an Inverted L.

Match List-I with List-II.

List-I (Translation)List-II (Function)
A. Aminoacyl-tRNA SynthetaseI. Formation of Peptide bond
B. 23S rRNA (Ribozyme)II. Terminates translation
C. Release FactorIII. Activation and charging of tRNA
D. UTR (Untranslated Region)IV. Efficiency of translation

[Molecular-Basis-of-Inheritance] [class-xii ]

  • A-III, B-I, C-II, D-IV
  • A-I, B-III, C-II, D-IV
  • A-III, B-II, C-I, D-IV
  • A-II, B-I, C-IV, D-III
  • Correct Option: A  [ A-III, B-I, C-II, D-IV ]

    Remark: Aminoacyl-tRNA Synthetase activates amino acids and links them to tRNA (charging). The 23S rRNA in bacteria acts as a Ribozyme (Peptidyl transferase) to form peptide bonds. Release Factors bind to stop codons to terminate the process. UTRs are regions before the start and after the stop codon that improve the efficiency of translation.

Match List-I with List-II.

List-I (Lac Operon Genes)List-II (Protein Product)
A. i geneI. Beta-galactosidase
B. z geneII. Repressor
C. y geneIII. Transacetylase
D. a geneIV. Permease

[Molecular-Basis-of-Inheritance] [class-xii ]

  • A-II, B-I, C-IV, D-III
  • A-II, B-IV, C-I, D-III
  • A-I, B-II, C-IV, D-III
  • A-III, B-I, C-II, D-IV
  • Correct Option: A  [ A-II, B-I, C-IV, D-III ]

    Remark: The i gene codes for the Repressor protein. The z gene codes for Beta-galactosidase (breaks down lactose). The y gene codes for Permease (transports lactose into cell). The a gene codes for Transacetylase.

Match List-I with List-II.

List-I (Lac Operon Regulation)List-II (Role)
A. Inducer (Lactose)I. Binding site for RNA Polymerase
B. RepressorII. Binds to Operator to block transcription
C. OperatorIII. Binding site for Repressor
D. PromoterIV. Binds to Repressor to inactivate it

[Molecular-Basis-of-Inheritance] [class-xii ]

  • A-IV, B-II, C-III, D-I
  • A-II, B-IV, C-III, D-I
  • A-IV, B-III, C-II, D-I
  • A-I, B-II, C-III, D-IV
  • Correct Option: A  [ A-IV, B-II, C-III, D-I ]

    Remark: Lactose acts as the Inducer by binding to the Repressor and inactivating it. The Repressor protein normally binds to the Operator region to physically block transcription. The Operator is the specific DNA sequence where the Repressor binds. The Promoter is the sequence where RNA Polymerase binds to initiate transcription.

Match List-I with List-II.

List-I (HGP Methodologies)List-II (Description)
A. Expressed Sequence Tags (ESTs)I. Sequencing both coding and non-coding regions
B. Sequence AnnotationII. Identifying genes expressed as RNA
C. BAC / YACIII. Automated DNA sequencing method
D. Sanger MethodIV. Vectors for cloning large DNA fragments

[Molecular-Basis-of-Inheritance] [class-xii ]

  • A-II, B-I, C-IV, D-III
  • A-I, B-II, C-IV, D-III
  • A-II, B-I, C-III, D-IV
  • A-III, B-IV, C-I, D-II
  • Correct Option: A  [ A-II, B-I, C-IV, D-III ]

    Remark: Expressed Sequence Tags (ESTs) involve sequencing only the genes that are expressed as RNA. Sequence Annotation involves sequencing the whole genome (coding and non-coding) and assigning functions later. BAC (Bacterial Artificial Chromosome) and YAC (Yeast Artificial Chromosome) are vectors used to clone large DNA fragments. The Sanger Method is the principle behind automated DNA sequencing.

Match List-I with List-II.

List-I (HGP Findings)List-II (Details)
A. Total base pairs (Haploid)I. Less than 2 percent
B. Protein coding genomeII. 3.3 Billion (approx)
C. Largest GeneIII. Chromosome 1
D. Most Genes (2968)IV. Dystrophin (2.4 million bases)

[Molecular-Basis-of-Inheritance] [class-xii ]

  • A-II, B-I, C-IV, D-III
  • A-II, B-IV, C-I, D-III
  • A-I, B-II, C-IV, D-III
  • A-IV, B-III, C-II, D-I
  • Correct Option: A  [ A-II, B-I, C-IV, D-III ]

    Remark: The human haploid genome contains approximately 3.3 billion base pairs (specifically 3.1647 billion). Less than 2% of the genome codes for proteins. The largest known human gene is Dystrophin, spanning 2.4 million bases. Chromosome 1 has the highest number of genes (2968).

Match List-I with List-II.

List-I (DNA Fingerprinting Steps)List-II (Action)
A. DigestionI. Transfer DNA to Nitrocellulose membrane
B. Gel ElectrophoresisII. Separation of DNA fragments by size
C. Southern BlottingIII. Cutting DNA with Restriction Endonucleases
D. HybridizationIV. Using labeled VNTR probes

[Molecular-Basis-of-Inheritance] [class-xii ]

  • A-III, B-II, C-I, D-IV
  • A-III, B-I, C-II, D-IV
  • A-II, B-III, C-I, D-IV
  • A-I, B-IV, C-II, D-III
  • Correct Option: A  [ A-III, B-II, C-I, D-IV ]

    Remark: Digestion refers to cutting DNA into fragments using restriction enzymes. Gel Electrophoresis separates these fragments based on size (smaller fragments move faster). Southern Blotting is the transfer of these separated fragments onto a synthetic membrane like nitrocellulose. Hybridization involves binding radioactive VNTR probes to specific complementary DNA sequences on the membrane.