NEET · Biology —

Molecular Basis of Inheritance appeared 4 times across 1 year — 4.4% of Biology. This question is from Transcription Unit Architecture.

Year 2024 Total
Questions 4 4
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Which of the following statements are correct with reference to a transcription unit? A. A transcription unit in DNA is defined primarily by three regions : promoter, structural gene and terminator. B. The promoter is said to be located towards the 5'-end of the structural gene. C. The promoter is a DNA sequence that provides binding site for RNA polymerase. D. The promoter defines the template and coding strands. E. The terminator is located towards the 3'-end of the coding strand and it defines the end of the process of transcription. Choose the correct answer from the options given below:

Solution & Explanation

Related Formula

Transcription Unit: Promoter (5'-end of coding strand) + Structural Gene + Terminator (3'-end of coding strand).

Core Logic
  • A: A transcription unit consists of promoter, structural gene, and terminator (True).
  • B: Promoter is at the 5'-end (upstream) relative to coding strand (True).
  • C: Promoter binds RNA polymerase (True).
  • D: Presence and orientation of promoter defines template vs coding strand (True).
  • E: Terminator is at 3'-end of coding strand and signals end of transcription (True).
Step 1: Conclusion

All statements A, B, C, D, and E are correct. Option (1) is correct.

Pattern Recognition

Every listed statement (A-E) is a verbatim accurate definition of a transcription unit from NCERT.

Chapter Mix

Class 12 Biology: Molecular Basis of Inheritance

Reference Study Guides

Molecular Basis Of Inheritance

More Molecular Basis of Inheritance Previous-Year Questions

Q116 neet_2024_05_may_morning DNA Fingerprinting Workflow
Arrange the following steps of DNA fingerprinting in a correct sequence. A. Isolation of DNA and its digestion by restriction endonucleases. B. Hybridisation using a labelled VNTR probe. C. Transferring of separated DNA fragments to synthetic membranes. D. Detection of hybridised DNA fragments by autoradiography. E. Separation of DNA fragments by electrophoresis. Choose the correct answer from the options given below:
  • A. A, E, C, B, D
  • B. A, E, B, C, D
  • C. A, B, D, C, E
  • D. A, D, B, E, C

Solution

Related Formula

DNA Fingerprinting Workflow: Isolation & Digestion arrow Gel Electrophoresis arrow Southern Blotting (Transfer) arrow Hybridization with Probe arrow Autoradiography.

Core Logic

Sequence of steps:

  • Isolation and digestion of DNA by restriction enzymes (A)
  • Separation of fragments by gel electrophoresis (E)
  • Transferring (blotting) to synthetic membrane (C)
  • Hybridisation using labelled VNTR probe (B)
  • Detection by autoradiography (D)
Step 1: Conclusion

The correct order is A arrow E arrow C arrow B arrow D. Correct option is (1).

Pattern Recognition

Blotting (C) must happen BEFORE hybridization (B), and autoradiography (D) is the final detection step. Order: A, E, C, B, D.

Chapter Mix

Class 12 Biology: Molecular Basis of Inheritance

Q123 neet_2024_05_may_morning DNA Packaging and Histones
Which of the following statements are correct with reference to packaging of DNA helix? A. Histones are organized to form a unit of eight molecules called histone octamer. B. Histones are negatively charged basic proteins. C. Histones are rich in the basic amino acid residues - lysine and arginine. D. The positively charged DNA is wrapped around the histone octamer to form nucleosome. E. The packaging of chromatin at higher levels requires an additional set of proteins called non-histone chromosomal proteins. Choose the correct answer from the options given below :
  • A. A, B and D only
  • B. A, C and E only
  • C. C, D and E only
  • D. B, D and E only

Solution

Related Formula

Histones: Positively charged, basic proteins (rich in Lysine and Arginine). DNA: Negatively charged (due to phosphate groups).

Core Logic
  • A: Histones form an 8-molecule unit (histone octamer) (True).
  • B: Histones are POSITIVELY charged basic proteins, not negatively charged (False).
  • C: Histones are rich in lysine and arginine (True).
  • D: DNA is NEGATIVELY charged, not positively charged (False).
  • E: Higher-level chromatin packing requires NHC (Non-Histone Chromosomal) proteins (True).
Step 1: Selection

Correct statements are A, C, and E. Option (2) is correct.

Pattern Recognition

Histones = Positively charged; DNA = Negatively charged. Spotting charge inversion in B and D eliminates 1, 3, 4.

Chapter Mix

Class 12 Biology: Molecular Basis of Inheritance

Q125 neet_2024_05_may_morning Lac Operon Structural Genes
In the lac operon, the z gene codes for
  • A. transacetylase
  • B. the repressor of lac operon
  • C. permease
  • D. beta-galactosidase

Solution

Related Formula

Lac Operon Genes: i gene arrow Repressor protein z gene arrow β-galactosidase y gene arrow Permease a gene arrow Transacetylase

Core Logic

In the lac operon of E. coli, structural gene z codes for β-galactosidase enzyme, which hydrolyzes lactose into glucose and galactose.

Step 1: Selection

The z gene codes for beta-galactosidase. Option (4) is correct.

Pattern Recognition

Lac Operon: z = β-galactosidase, y = permease, a = transacetylase.

Chapter Mix

Class 12 Biology: Molecular Basis of Inheritance

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JEE Physics: Waves (+15.5%) | Electrostatics: Concentric Shells (-29.7%) | Modern Physics: Photoelectric Clones (+34.2%) | Mathematics: Definite Integrals (+18.1%) | Chemistry: Coordination Splitting (-11.4%) | JEE Physics: Waves (+15.5%) | Electrostatics: Concentric Shells (-29.7%) | Modern Physics: Photoelectric Clones (+34.2%) | Mathematics: Definite Integrals (+18.1%) | Chemistry: Coordination Splitting (-11.4%)