1. Who were the scientists credited with the discovery of the structure of DNA?
Answer:
Explanation:
James Watson and Francis Crick are credited with proposing the double helical structure of DNA in 1953.
2. Which nitrogenous base is exclusive to RNA?
Answer:
Explanation:
RNA contains Uracil instead of Thymine which is present in DNA.
3. Which enzyme aids in the replication of DNA by adding nucleotides to the growing DNA chain?
Answer:
Explanation:
DNA polymerase is responsible for the elongation of the new DNA strand during replication.
4. Which process involves the synthesis of RNA from a DNA template?
Answer:
Explanation:
Transcription is the process where RNA is synthesized using a DNA template.
5. Which type of RNA brings amino acids to the ribosome during protein synthesis?
Answer:
Explanation:
tRNA (transfer RNA) carries amino acids to the ribosome for protein synthesis.
6. Which of the following is not a stop codon?
Answer:
Explanation:
AUG is a start codon, which signals the start of translation. It codes for the amino acid methionine.
7. Which phenomenon involves the transfer of a DNA segment from one bacterium to another?
Answer:
Explanation:
Transformation is the uptake of foreign DNA from the surrounding environment by a bacterium.
8. The lac operon is usually switched off when:
Answer:
Explanation:
In the absence of lactose, the repressor protein binds to the operator, preventing RNA polymerase from transcribing the operon.
9. Which technique is used to separate DNA fragments based on their size?
Answer:
Explanation:
Gel electrophoresis separates DNA fragments based on their size using an electric field.
10. Which enzyme is used to produce cDNA from mRNA?
Answer:
Explanation:
Reverse transcriptase synthesizes complementary DNA (cDNA) from an mRNA template.
11. Which scientist provided evidence on the semiconservative mode of DNA replication?
Answer:
Explanation:
Meselson and Stahl's experiments in 1958 demonstrated the semiconservative nature of DNA replication.
12. In which organelle does translation occur?
Answer:
Explanation:
Ribosomes are the sites of protein synthesis, where translation occurs.
13. What is the role of the promoter in transcription?
Answer:
Explanation:
The promoter is a DNA sequence that directs the RNA polymerase where to start transcription.
14. The genetic code is:
Answer:
Explanation:
The genetic code is degenerate, meaning multiple codons can code for the same amino acid.
15. Which enzyme helps in the formation of phosphodiester bonds between DNA fragments?
Answer:
Explanation:
DNA ligase aids in forming phosphodiester bonds, thus sealing breaks in the DNA.
16. Which enzyme is crucial for the amplification of DNA during PCR?
Answer:
Explanation:
Taq polymerase is a heat-stable enzyme used in PCR to amplify DNA.
17. Which molecule acts as a molecular switch in the regulation of gene expression in prokaryotes?
Answer:
Explanation:
The repressor protein can bind to the operator sequence and prevent transcription.
18. How many nucleotide bases code for one amino acid?
Answer:
Explanation:
Three nucleotide bases form a codon, which codes for a specific amino acid.
19. Which form of RNA has a cloverleaf structure?
Answer:
Explanation:
tRNA (transfer RNA) has a characteristic cloverleaf structure.
20. Which of the following sequences can be recognized and cut by a restriction enzyme?
Answer:
Explanation:
Restriction enzymes recognize and cut specific palindromic DNA sequences.