MCQ on Transcription

MCQ on Transcription: Transcription is the process by which a cell makes an mRNA from DNA. Transcription is a process that occurs in all living cells. This mRNA carries the genetic information needed to make proteins in a cell. It carries information from the DNA in the cell’s nucleus to the cytoplasm, where proteins are made.

The DNA within the cell provides the transcript, or blueprint, which determines the sequence of nucleotides that are joined together to form RNA. In eukaryotes, transcription takes place in the nucleus. In prokaryotes, the transcription process takes place in the cytoplasm.

Transcription is carried out by an enzyme called RNA polymerase and several accessory proteins called transcription factors. To start the transcription process, RNA polymerase binds to the DNA molecule in a specific region called the promoter.

Transcription factors can bind to specific DNA sequences called enhancer and promoter sequences to recruit RNA polymerase to an appropriate transcription site.  Together, transcription factors and RNA polymerase form a complex called the transcription initiation complex.A transcription unit is the chain of nucleotides on a strand of DNA that starts at the initial code and continues through the final code.

MCQ on Transcription in Eukaryotes and Prokaryotes: 

1. Transcription is the transfer of genetic information from
(1) DNA to RNA
(2) tRNA to mRNA
(3) DNA to mRNA
(4) mRNA to tRNA
Answer: 1
Explanation: Transcription is the process by which a segment of DNA is copied into RNA, especially mRNA, by the enzyme RNA polymerase.

2. The enzyme required for transcription is
(1) RNAase
(2) DNA polymerase
(3) RNA polymerase
(4) Restriction enzymes
Answer: 3
Explanation: RNA polymerase is the key enzyme that catalyzes the synthesis of RNA from a DNA template during transcription.

3. The site of insulin gene transcription in islet B cells is
(1) ribosome
(2) centrosome
(3) Golgi body
(4) nucleus
Answer: 4
Explanation: In eukaryotic cells, transcription occurs inside the nucleus, where the DNA is located, including the insulin gene in beta cells.

4. Transcription in eukaryotes is initiated when
(1) RNA strand is present
(2) RNA polymerase is present
(3) Core promoter sequence is present
(4) None of these
Answer: 3
Explanation: Transcription begins when RNA polymerase binds to the promoter region, a specific DNA sequence upstream of the gene.

5. Mark the one, which is NOT the transcription inhibitor in eukaryotes.
(1) Rifampicin
(2) Acridine dye
(3) Actinomycin D
(4) Rho factor
Answer: 4
Explanation: Rho factor is involved in transcription termination in prokaryotes, not eukaryotes. The others are inhibitors that affect transcription in eukaryotes.

6. In a chain of a DNA molecule, the proportion of base C in the chain is 36%, and the proportion of base G in the mRNA transcribed from it as a template is
(1) 18%
(2) 36%
(3) 50%
(4) 64%
Answer: 2
Explanation: C pairs with G in DNA. If DNA has 36% C, the complementary strand (template) will have 36% G, so the RNA transcribed will have 36% C (since G in DNA pairs with C in RNA).

7. Transcription is the transfer of genetic information from
(1) DNA to RNA
(2) DNA to mRNA
(3) mRNA to tRNA
(4) tRNA to mRNA
Answer: 2
Explanation: During transcription, the genetic code from DNA is transcribed into messenger RNA (mRNA), which carries the information for protein synthesis.

8. A DNA sequence is read by an RNA polymerase that produces a complementary antiparallel RNA strand known as
(1) Hexa transcript
(2) Secondary transcript
(3) Primary transcript
(4) Tertiary transcript
Answer: 3
Explanation: The primary transcript is the initial RNA molecule synthesized from the DNA template before any processing.

9. Which of the following is not required for the transcription of genetic information
(1) Helicase
(2) ATP
(3) Template chain
(4) Amino acid
Answer: 4
Explanation: Amino acids are required for translation, not transcription. Transcription only requires the DNA template, RNA polymerase, NTPs, and energy.

10. The process of formation of RNA is known as
(1) Replication
(2) DNA repair
(3) Translation
(4) Transcription
Answer: 4
Explanation: Transcription is the synthesis of RNA from a DNA template. Replication is DNA to DNA, while translation is RNA to protein.

11. Which of these RNA polymerase subunits is required to initiate transcription?
(1) alpha (α)
(2) sigma (σ)
(3) omega (ω)
(4) beta (β)
Answer: 2
Explanation: The sigma (σ) subunit of RNA polymerase is responsible for recognizing the promoter region and initiating transcription in prokaryotes.

12. Name the one intrinsic terminator of transcription.
(1) Intercalating agents
(2) Rho-independent
(3) Rho-dependent
(4) Acridine orange
Answer: 2
Explanation: Rho-independent termination occurs due to specific sequences in the RNA forming a hairpin loop followed by a series of uracils, leading to the release of RNA polymerase without external factors.

13. Transcribe mRNA with the complementary strand of “-CAATTC-“, then the sequence of this mRNA is
(1) GAAUUG
(2) CTTAAC
(3) CUUAAC
(4) GAATTG
Answer: 1
Explanation: The complementary DNA strand for CAATTC is GTTAAG. Transcription uses this as a template to make mRNA: GAAUUG (T is replaced by U in RNA).

14. What is the work of the sigma factor in transcription?
(1) Helicase action
(2) Transcription initiation
(3) Transcription elongation
(4) Transcription termination
Answer: 2
Explanation: The sigma factor directs RNA polymerase to the promoter region, helping initiate transcription. It detaches after initiation.

15. Which of the following transcription termination techniques has RNA-dependent ATPase activity?
(1) Intercalating agents
(2) Rho-dependent
(3) Rho-independent
(4) Rifampicin
Answer: 2
Explanation: Rho-dependent termination involves the Rho factor, which has RNA-dependent ATPase activity and causes release of RNA from the transcription complex.

16. To simulate the transcription process in the organism, the necessary conditions are
(1) ①②④⑤⑦⑧
(2) ①④⑤⑥⑦⑧
(3) ①②③⑤⑦⑧
(4) ①③⑤⑥⑦⑧
Answer: 4
Explanation: Transcription requires RNA polymerase (①), free ribonucleotides (③), DNA template (⑤), energy (ATP – ⑥), and appropriate conditions like temperature (⑦) and pH (⑧). DNA polymerase and deoxynucleotides are not involved.

17. From the perspective of the transmission process of genetic information, the main function of messenger RNA (mRNA) can be expressed as
(1) Transfer genetic information from DNA to proteins
(2) The genetic information of translated DNA
(3) The genetic information of transcribed DNA
(4) As a template for RNA synthesis
Answer: 1
Explanation: mRNA acts as a messenger carrying genetic instructions from DNA in the nucleus to the ribosome for protein synthesis.

18. Which statement about transfer RNA is true?
(1) An amino acid can be carried by one or more transfer RNAs
(2) Transfer RNA is synthesized in the cytoplasm
(3) A transfer RNA has only three bases
(4) Each amino acid has its own specific type of transfer RNA
Answer: 1
Explanation: There can be multiple tRNAs (isoacceptors) for the same amino acid due to codon degeneracy. tRNA is synthesized in the nucleus, not cytoplasm.

19. DNA replication and transcription have in common
(1) Requires multiple enzymes to participate
(2) Occurs in the nucleus
(3) Follow the principle of complementary base pairing
(4) All of these
Answer: 4
Explanation: Both processes are nuclear, enzyme-driven, and rely on base-pairing rules—A with T/U, and G with C.

20. False statement about the two processes of DNA replication and transcription in eukaryotic cells
(1) Both processes can occur in the nucleus
(2) Enzymes are involved in both processes
(3) Both processes use deoxyribonucleotides as raw materials
(4) Both processes use DNA as a template
Answer: 3
Explanation: Transcription uses ribonucleotides (ATP, UTP, CTP, GTP), not deoxyribonucleotides (dATP, dTTP, etc.).

21. Which of the following statements about the role of the “RNA polymerase binding site” in the gene structure is false?
(1) The “RNA polymerase binding site” is the start codon
(2) An “RNA polymerase binding site” is a binding site to which RNA polymerase binds when RNA is transcribed
(3) The “RNA polymerase binding site” enables the enzyme to accurately recognize the initiation site of transcription and initiate transcription
(4) “RNA polymerase binding site” regulates mRNA transcription
Answer: 1
Explanation: The start codon is involved in translation, not transcription initiation. The RNA polymerase binding site is the promoter region.

22. The base sequence of the template DNA is 3′-TGCAGT-5′, and the base sequence of the transcribed RNA is
A. 5′-AGGUCA-3′
B. 5′-ACGUCA-3′
C. 5′-UCGUCU-3′
D. 5′-ACGTCA-3′
Answer: B
Explanation: The RNA is synthesized 5′ to 3′ complementary to the 3′ to 5′ DNA strand. T → A, G → C, C → G, A → U.

23. RNA can be synthesized by using vector. A vector with _______ is used and further through ________ RNA is isolated.
A. origin of replication, translation
B. promoter, transcription
C. promoter, translation
D. origin of replication, transcription
Answer: B
Explanation: RNA synthesis requires a promoter on the vector for transcription to begin and isolate the RNA product.

24. The RNA synthesized by eukaryotic RNA polymerase II is
A. rRNA
B. mRNA
C. tRNA
D. 5S rRNA
Answer: B
Explanation: RNA polymerase II synthesizes messenger RNA (mRNA) in eukaryotic cells.

25. The factor that recognizes the termination of RNA transcription is
A. alpha factor
B. beta factor
C. Sigma factor
D. Rho factor
Answer: D
Explanation: Rho factor is a protein in prokaryotes that binds to RNA and terminates transcription (Rho-dependent termination).

26. Which of the following statements about DNA-directed RNA synthesis is false?
A. RNA polymerase can catalyze the formation of phosphodiester bonds only in the presence of DNA
B. RNA polymerase needs primers during transcription
C. The direction of RNA strand synthesis is 5′ → 3′
D. In most cases only one strand of DNA acts as a template for RNA
Answer: B
Explanation: Unlike DNA polymerase, RNA polymerase does not need a primer to initiate synthesis.

27. DNA-guided RNA polymerase consists of several subunits, and its core enzyme composition is
A. ααββ’
B. ααββ′σ
C. ααβ’
D. ααβ
Answer: A
Explanation: The core enzyme of bacterial RNA polymerase is composed of two alpha (α), one beta (β), and one beta prime (β′) subunit.

28. Identify the start point of transcription is
A. Rho factor
B. Core enzyme
C. The sigma factor of RNA polymerase
D. The alpha subunit of RNA polymerase
Answer: C
Explanation: The sigma factor guides RNA polymerase to the promoter, determining the transcription start site.

29. Which of the following statements about the sigma factor is correct?
A. A subunit of RNA polymerase responsible for recognizing a specific starting point for transcription of RNA on a DNA template
B. A subunit of DNA polymerase that can bidirectionally synthesize RNA in the 5’→3′ and 3’→5′ directions
C. Recognizes termination signals on DNA templates
D. Is a small molecule organic compound
Answer: A
Explanation: Sigma factor helps the RNA polymerase enzyme recognize promoter sequences and initiate transcription correctly.

30. Which of the following statements about DNA replication and transcription is false?
A. In vivo, one DNA strand is used as a template to transcribe and two DNA strands are used as a template to replicate
B. In both processes, the synthesis direction is 5’→3′
C. The product of replication is usually larger than the product of transcription
D. Both processes require RNA primers
Answer: D
Explanation: Only DNA replication requires RNA primers. Transcription can start de novo using RNA polymerase.