Question
The correct statement with regard to the secondary structure of DNA/RNA is :
This question was previously asked in
NEET UG Re-Exam 2026 Question Paper (21-Jun-2026)
The correct answer is
DNA possesses a double strand helix structure and contains thymine as one of the four bases.
DNA and RNA Structure Basics
Understanding the fundamental differences between Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA) is key to analyzing their secondary structures.
DNA Secondary Structure
- DNA typically forms a double-stranded helix structure.
- The four bases in DNA are Adenine (A), Guanine (G), Cytosine (C), and Thymine (T).
RNA Secondary Structure
- RNA generally exists as a single-stranded helix, though it can fold upon itself to form complex secondary structures.
- The four bases in RNA are Adenine (A), Guanine (G), Cytosine (C), and Uracil (U). Thymine is absent in RNA.
Analyzing Secondary Structure Statements
Evaluating the given options based on these characteristics:
- Option 1: Incorrect. States DNA is single-stranded and contains Uracil. DNA is double-stranded and uses Thymine.
- Option 2: Correct. Accurately states DNA possesses a double-stranded helix structure and contains Thymine.
- Option 3: Incorrect. RNA is primarily single-stranded, not typically double-stranded.
- Option 4: Incorrect. States RNA contains Thymine. RNA uses Uracil instead of Thymine.
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Similar Questions
- 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 : - In the lac operon, the z gene codes for :
- 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 : - 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 : - Which of the following statements about lac-operon is correct ?
- Which of the following enzymes synthesizes precursor mRNA ?
Important Questions from Molecular Biology
- 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 : - In the lac operon, the z gene codes for :
- 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 : - 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 : - Which of the following statements about lac-operon is correct ?
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