NEET Biology: Nucleic Acids Practice Questions
14 free multiple-choice questions on Nucleic Acids for NEET Biology, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more Nucleic Acids questions in the app →Q1. The directionality of a nucleic acid strand, which dictates the orientation of the chain, is defined by which convention?
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Correct answer: B — 5' to 3'
The directionality of nucleic acid strands is conventionally described from the 5' end to the 3' end.
Q2. What is the fundamental chemical difference between DNA and RNA regarding their sugar component?
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Correct answer: C — DNA has deoxyribose while RNA has ribose
DNA contains deoxyribose sugar, whereas RNA contains ribose sugar.
Q3. Which of the following is a monomer unit of DNA and RNA?
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Correct answer: B — Nucleotide
Nucleotides are the fundamental building blocks (monomers) of DNA and RNA.
Q4. In the formation of the standard double helix structure of DNA, the hydrogen bonds between complementary base pairs are primarily responsible for which structural feature?
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Correct answer: A — Creating the overall stability of the helix
The specific arrangement of hydrogen bonds between complementary bases (A-T and G-C) is crucial for holding the two strands together to form the stable double helix structure.
Q5. The structural backbone of a nucleic acid is formed by the linkage of which functional group between adjacent nitrogenous bases?
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Correct answer: A — Phosphate group
The backbone of DNA and RNA consists of alternating sugar and phosphate groups. The phosphate group links the sugar molecules together to form the backbone.
Q6. Which of the following nucleic acids functions primarily as an intermediary in protein synthesis by carrying amino acids from the ribosome?
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Correct answer: B — Transfer RNA (tRNA)
tRNA (Transfer RNA) plays the crucial role in bringing specific amino acids to the ribosome during translation.
Q7. Which of the following nitrogenous bases pairs with Guanine (G) in the DNA double helix structure?
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Correct answer: B — Cytosine (C)
In DNA, Guanine always pairs with Cytosine (G-C pairing).
Q8. The polarity of the sugar molecule in RNA is primarily characterized by the presence of a hydroxyl group (-OH) at which carbon position compared to DNA?
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Correct answer: B — C3
Ribose (in RNA) has a hydroxyl group on the 2' carbon, while deoxyribose (in DNA) has a hydrogen atom at that position (hence the 'deoxy').
Q9. The primary role of transfer RNA (tRNA) molecules in protein synthesis is to facilitate which specific process?
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Correct answer: D — Transporting specific amino acids to the ribosome
tRNA molecules act as adaptors, carrying specific amino acids to the ribosome based on the mRNA codon sequence, which is essential for polypeptide chain elongation.
Q10. In RNA molecules, which nitrogenous base is typically found in place of Thymine found in DNA?
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Correct answer: C — Uracil
RNA contains Uracil (U) instead of Thymine (T) in its structure. This substitution is a key chemical difference between DNA and RNA.
Q11. Which type of glycosidic bond links the nitrogenous bases in a nucleic acid structure?
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Correct answer: D — Glycosidic bond
Nitrogenous bases in nucleic acids are linked by glycosidic bonds.
Q12. Which component is common to both DNA and RNA molecules, forming the backbone structure?
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Correct answer: C — Phosphate group
The backbone of both DNA and RNA is a polymer chain formed by linking the phosphate group of one nucleotide to the sugar of the next nucleotide via phosphodiester bonds. The phosphate group is a universal component of the backbone structure.
Q13. The specific pairing mechanism between complementary nitrogenous bases in a DNA double helix is stabilized by which type of bonds?
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Correct answer: D — Hydrogen bonds only
The complementary pairing of A-T and G-C bases in DNA is maintained by specific hydrogen bonds, which hold the two strands together to form the double helix structure.
Q14. Which of the following accurately describes the monomer unit of a nucleic acid chain?
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Correct answer: B — Nucleotide
The monomer unit that links together to form a polynucleotide chain (DNA or RNA) is the nucleotide, which consists of a nitrogenous base, a pentose sugar, and a phosphate group.
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