Free Structure of DNA MCQs with Answers
69 Structure of DNA MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
DNA structure includes nucleotides made of deoxyribose, phosphate and nitrogenous bases, arranged in two antiparallel polynucleotide strands. Questions cover the double helix, phosphodiester and hydrogen bonds, complementary base pairing between adenine and thymine and between guanine and cytosine, and the significance of major and minor grooves.
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- A. Consists of few DNA nucleotides
- B. Helps lo unwind DNA double strand
- C. Prevents DNA strands to pair up
- D. Is a short segment of RNA nucleotides
Explanation: DNA polymerase - an enzyme that adds new nucleotides to a growing strand of DNA.
Correct answer: Is a short segment of RNA nucleotides- A. 0 minutes
- B. 20 minutes
- C. 40 minutes
- D. 60 minutes
Explanation: Right after adding the N15 label, the DNA sample would contain only the heavy isotope N15, so it would appear heaviest at this point.
Correct answer: 0 minutes- A. C5H10O5
- B. C5H8O4
- C. C5H10O4
- D. C5H8O3
- E. C5H10O3
Explanation: Explanation for this question will be added soon.
Correct answer: C5H10O4- A. 0
- B. 1
- C. 2
- D. 3
Explanation: Option A: This option suggests that there are no hydrogen bonds in a Cytosine-Guanine pair.
Correct answer: 3- A. Parallel
- B. Both A, C
- C. Antiparallel
- D. None of these
Explanation: Coiling of two strands is opposite i.e they are coiled antiparallel to each other.
Correct answer: Antiparallel- A. CGAUACC
- B. CGTATGC
- C. CGATACC
- D. CGUTCC
Explanation: ExplanationThe mRNA would be complementary to the given DNA strand. RNA has Uracil Base instead of thymine.
Correct answer: CGAUACC- A. Dehydration
- B. Oxidation
- C. Rehydration
- D. Reduction
Explanation: Explanation:This is a dehydration reaction involving the formation of phosphodiester bonds.This option is incorrect.
Correct answer: Dehydration- A. Restriction endonuclease
- B. DNA helicase
- C. Primase
- D. DNA ligase
Explanation: Explanation:DNA Ligase is an enzyme that catalyzes the formation of a phosphodiester bond between adjacent Okazaki fragments on the…
Correct answer: DNA ligase- A. Uracil
- B. Thymine
- C. Cytosine
- D. Adenine
Explanation: [A] Uracil is a pyramiding present in RNA but not in DNA[B] Thymine(pyrimidine) is present in DNA[C] Cytosine(pyrimidine) is also present…
Correct answer: Uracil- A. Insertion
- B. Transposition
- C. Deletion
- D. Base Substitution
Explanation: In Sickle cell anemia, the gene for beta-globin is mutated. As a result, the amino acid valine is replaced by glutamic acid and the RBC…
Correct answer: Base Substitution- A. Uracil
- B. Thymine
- C. Guanine
- D. Cytosine
Explanation: The given structure is of a pyrimidine base which bears resemblance to the structure of Cytosine.
Correct answer: Cytosine- A. Making proteins.
- B. Making amino acids.
- C. Breakdown of ribose sugar
- D. Carries genetic material.
Explanation: DNA is a hereditary material which carries the genetic information generation after generation.
Correct answer: Carries genetic material.- A. rRNA
- B. mRNA
- C. DNA
- D. Nucleotides
Explanation: A DNA molecule is a double helix carrying the genetic information of an organism.
Correct answer: DNA- A. CACGTC
- B. TAGCATG
- C. TACGAG
- D. GACGTG
Explanation: In DNA, the base pairs are complementary to each other. Adenine (A) always pairs with thymine (T), and guanine (G) always pairs with…
Correct answer: TACGAG- A. Parallel
- B. Antiparallel
- C. ......
- D. None
Explanation: Each strand has a backbone made up of alternating sugars and phosphate groups.
Correct answer: Antiparallel- A. Cytosine
- B. Adenine
- C. Uracil
- D. Thymine
Explanation: Purines, such as adenine and guanine, have a double-ringed structure - one hexagonal pyrimidine ring and an imidazole ring.
Correct answer: Adenine- A. AUAGA
- B. ATACA
- C. UAUGU
- D. ATACT
Explanation: Nucleotides are the building blocks of nucleic acids, i.e., DNA and RNA.
Correct answer: ATACT- A. One
- B. Two
- C. Three
- D. Four
Explanation: RNA (Ribonucleic Acid) and DNA (Deoxyribonucleic Acid) differ in their sugar components.
Correct answer: One- A. Interphase
- B. Prophase
- C. Metaphase
- D. Anaphase
Explanation: The correct answer is Interphase. During interphase, the cell prepares for division, and the DNA in the nucleus replicates.
Correct answer: Interphase- A. Bacteria
- B. Virus
- C. Eukaryote
- D. All of the above
Explanation: In eukaryotes, such as humans, DNA replication occurs at approximately 50 base pairs per second.
Correct answer: Eukaryote