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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 regarding the deciphering of the Genetic Code.

List-I (Scientist)List-II (Contribution)
A. George GamowI. Cell-free system for protein synthesis
B. Har Gobind KhoranaII. Enzyme for template-independent RNA synthesis
C. Marshall NirenbergIII. Synthesized RNA homopolymers chemically
D. Severo OchoaIV. Proposed that the code is a Triplet

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

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

    Remark: George Gamow (a physicist) proposed that the genetic code must be a triplet. Har Gobind Khorana synthesized RNA molecules (homopolymers and copolymers) chemically. Marshall Nirenberg developed a cell-free system for protein synthesis. Severo Ochoa discovered the enzyme Polynucleotide Phosphorylase for template-independent RNA synthesis,,.

Match List-I with List-II regarding the steps and components of DNA Fingerprinting.

List-I (Component/Step)List-II (Function/Description)
A. VNTRI. Transfer of DNA to synthetic membrane
B. ProbeII. Separation of DNA fragments by size
C. Southern BlottingIII. Mini-satellite used as marker
D. ElectrophoresisIV. Radioactive DNA detecting specific sequences

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

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

    Remark: VNTR (Variable Number of Tandem Repeats) is a mini-satellite used as the basis for fingerprinting. A Probe is a radioactive single-stranded DNA used to hybridize with the target sequence. Southern Blotting is the transfer of DNA from gel to a membrane. Electrophoresis separates DNA fragments based on size,,,.

Match List-I with List-II regarding types of RNA and their roles.

List-I (RNA)List-II (Function)
A. mRNAI. Adapter molecule
B. tRNAII. Precursor to mRNA in eukaryotes
C. rRNAIII. Template for protein synthesis
D. hnRNAIV. Structural and Catalytic role

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

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

    Remark: mRNA acts as the template or messenger for protein synthesis. tRNA acts as an adapter molecule that reads the code and brings amino acids. rRNA plays a structural and catalytic (ribozyme) role in the ribosome. hnRNA (Heterogeneous Nuclear RNA) is the precursor to mRNA found in eukaryotes,,,.

Match List-I with List-II regarding Eukaryotic RNA Polymerases.

List-I (Enzyme)List-II (Product)
A. RNA Polymerase II. hnRNA (Precursor to mRNA)
B. RNA Polymerase IIII. tRNA, 5S rRNA, snRNA
C. RNA Polymerase IIIIII. rRNAs (28S, 18S, 5.8S)

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

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

    Remark: In eukaryotes, RNA Polymerase I transcribes large rRNAs (28S, 18S, 5.8S). RNA Polymerase II transcribes hnRNA, which is processed into mRNA. RNA Polymerase III transcribes tRNA, 5S rRNA, and snRNAs. This can be remembered with the mnemonic "RaMeT" (I-rRNA, II-mRNA, III-tRNA).

Match List-I with List-II regarding the Translation process.

List-I (Step)List-II (Description)
A. Charging of tRNAI. Release Factors bind to Stop codon
B. InitiationII. Peptide bond formation by 23S rRNA
C. ElongationIII. Aminoacylation (Activation of amino acid)
D. TerminationIV. Small ribosomal subunit binds to mRNA

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

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

    Remark: Charging or aminoacylation is the activation of amino acids and binding to tRNA. Initiation involves the binding of the small ribosomal subunit to the mRNA (Shine-Dalgarno or Cap). Elongation involves the formation of peptide bonds, catalyzed by the ribozyme (23S rRNA). Termination occurs when Release Factors bind to the Stop codon,,,.

Match List-I with List-II regarding properties of the Genetic Code.

List-I (Property)List-II (Explanation)
A. DegenerateI. One codon codes for only one amino acid
B. UnambiguousII. Code is nearly the same across all organisms
C. UniversalIII. Multiple codons can code for the same amino acid
D. Comma-lessIV. Read continuously without punctuation

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

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

    Remark: Degenerate means that some amino acids are coded by more than one codon (e.g., Leucine). Unambiguous means a specific codon codes for only one specific amino acid. Universal means the code is shared by nearly all organisms. Comma-less means the code is read contiguously without pauses,,,.

Match List-I with List-II regarding DNA Replication Enzymes.

List-I (Enzyme)List-II (Function)
A. HelicaseI. Joins Okazaki fragments (Molecular Glue)
B. TopoisomeraseII. Synthesizes RNA primer
C. PrimaseIII. Unzips/Unwinds the DNA helix
D. DNA LigaseIV. Relieves tension/supercoiling

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

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

    Remark: Helicase unzips the DNA helix by breaking hydrogen bonds. Topoisomerase relieves the tension/supercoiling ahead of the fork. Primase synthesizes the RNA primer needed to start replication. DNA Ligase joins the discontinuous Okazaki fragments,,,.

Match List-I with List-II regarding the structure of tRNA.

List-I (Feature)List-II (Description)
A. 2D StructureI. Reads the codon on mRNA
B. 3D StructureII. Clover-leaf shape
C. Acceptor ArmIII. Inverted L shape
D. Anticodon LoopIV. Binds to Amino Acid

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

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

    Remark: The 2D structure of tRNA resembles a Clover-leaf. The 3D structure resembles an Inverted L. The Acceptor Arm (3-prime end) binds to the amino acid. The Anticodon loop contains the sequence that reads the mRNA codon,.

Match List-I with List-II regarding experiments on Genetic Material.

List-I (Scientist)List-II (Discovery)
A. Frederick GriffithI. Unequivocal proof using Bacteriophage
B. Hershey and ChaseII. Semi-conservative replication in Vicia faba
C. Meselson and StahlIII. Transforming Principle
D. Taylor and colleaguesIV. Semi-conservative replication in E. coli

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

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

    Remark: Griffith described the Transforming Principle. Hershey and Chase provided unequivocal proof that DNA is the genetic material. Meselson and Stahl proved semi-conservative replication in E. coli using N-15. Taylor and colleagues proved semi-conservative replication in eukaryotes (Vicia faba) using radioactive thymidine,,,.

Match List-I with List-II regarding RNA Processing.

List-I (Process)List-II (Feature)
A. CappingI. Removal of Introns
B. TailingII. Addition of Methyl Guanosine Triphosphate
C. SplicingIII. Addition of Adenylate residues (Poly-A)
D. ExonsIV. Coding sequences retained in mature RNA

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

    Remark: Capping involves adding Methyl Guanosine Triphosphate to the 5-prime end. Tailing involves adding Adenylate residues (Poly-A tail) to the 3-prime end. Splicing is the removal of non-coding Introns. Exons are the coding sequences that are retained in the mature mRNA,,.