複選題

13. Which is true for eukaryotic transcription activators?
(A) A type II nuclear receptor exists an inactive form in cytoplasm before binding to its ligand.
(B) Yeast Gal4 is a Cys2His2 zinc-finger protein, involving in regulation of galactose metabolism.
(C) The basic region of a bHLH transcription factor is involved in protein dimerization.
(D) Type III nuclear receptors are also known as orphan receptors and bind to DNA as homodimers.
(E) In the bZIP transcription factor, the bZIP domain consists of two alpha-helix polypeptides, each with leucine residues separated by 5 amino acids.

9. Which is true for the following experimental techniques?(A) Yeast two-hybrid analysis is useful for assaying DNA-protein interactions invitro.(B) In chromatin immunoprecipitation (ChIP) analysis, formaldehyde iscommonly used for protein-DNA crosslinking.(C) Far-western blot analysis is a method to analyze protein-RNA interactions.(D) The G-less cassette assay is often used to detect protein-protein interactions.(E) A Southern blot is used to detect specific protein in a tissue sample.

10.Which statement is not true for TATA-binding protein (TBP) of eukaryoticRNA polymerases (RNAPs)?(A) RNAP III is positioned at promoter by a TFIIIC, which contains TВР.(B) For RNAP II, TBP is a component of the general transcription factor TFIID.(C) For RNAP I in human, the general transcription factor SL1 is composed ofTBP and three TAFS, and binds to the core promoter region.(D) TBP binds to the minor groove of DNA and bends consensus TATA DNA byapproximately 80 degree.(E) In yeast, TFIIB binds specifically to TBP via its C-terminal domain.

11.Which statement is true for the general transcription factors in eukaryoticorganisms?(A) TFIIE, TFIIF and TFIIH are not essential for transcription elongation, butthey are required for promoter clearance.(B) The core-binding factor is the fundamental transcription factor required torecruit RNA polymerase I.(C) During transcription elongation, RNA polymerases may pause at specificsites near promoters, and this pause can be reversed by TFIIB.(D) Transcription of the 5S rRNA gene requires TFIIIA and TFIIIB, but notTFIIIC.(E) TAF2 and TAF5 can bind to TATA-less promoters that contains the Inr andDPE promoter elements to ensure the whole TFIID binding to the promoter.

12. Which of the following RNA undergoes two additional processes known ascapping and tailing?(A) sIRNA(B) tRNA(C) snRNA(D) 5S rRNA(E) hn RNA

14. Choose a correct statement for eukaryotic promoters. (A) Spacing between the core element and upstream promoter element (UPE) is not important for the transcription of class I promoters. (B) At least in Drosophila, TATA-less of class II promoters tend to have downstream promoter elements (DPEs) that are similar to TATA box, bound by TFIIB. (C) Inr (initiator) and the TATA box constitutes a core promoter for the adenovirus major late promoter. (D) The tRNA gene contains an internal promoter, which is split into three regions: box A, a short intermediate element, and Box C. (E) The AT-rich initiator (rINR) is a conserved sequence of class I promoters and is located within the upstream promoter element (UPE).

15. Which of the following statements is INCORRECT about the canonicalmicroRNA (miRNA) biogenesis pathway in mammals?(A) Pri-miRNAs are typically transcribed by RNA polymerase II and contain a 5'cap and polyA. tail.(B) The Microprocessor complex, composed of Drosha and DGCR8, cleaves primiRNAs in the nucleus to generate pre-miRNA hairpins.(C) Exportin-5, in a Ran-GTP-dependent manner, exports pre-miRNAs from thenucleus into the cytoplasm.(D) Dicer cleaves the pre-miRNA in the cytoplasm, producing a short duplex(~22 nucleotides), which then undergoes strand selection.(E) The mature miRNA is incorporated into the RNA-induced silencing complex(RISC) through the Drosha-DGCR8 complex.

16. Which of the following is the primary biological function of microRNAS (miRNAs) in eukaryotic cells? (A) To serve as templates for the synthesis of small interfering RNAs (siRNAS) during immune response. (B) To promote the splicing of pre-mRNA by recognizing intron-exon junctions. (C) To regulate gene expression by binding to complementary sequences on target mRNAs, leading to translational repression or mRNA degradation. (D) To act as ribozymes that catalyze peptide bond formation during protein synthesis. (E) To serve as direct messengers in the nucleus that enhance transcription by interacting with RNA polymerase II.

17. Which of the following statements correctly describes a key difference between microRNAs (miRNAs) and small interfering RNAs (siRNAs)? (A) miRNAs primarily regulate gene expression through translational repression, while siRNAs often induce mRNA cleavage when binding to their target. (B) miRNAs typically bind to perfectly complementary sequences on target mRNAs, while siRNAs bind to partially complementary sequences. (C) siRNAs are derived from endogenous transcripts, while miRNAs are always of exogenous origin. (D) Both miRNAs and siRNAs are loaded onto the RNA-induced silencing complex (RISC), but only siRNAs recruit the Argonaute protein. (E) miRNAs are processed in the cytoplasm by Dicer, while siRNAs are processed exclusively in the nucleus. 

18. What is the primary purpose of RNA polyadenylation in eukaryotic cells? (A) To prevent the formation of secondary structures in the coding region of the mRNA. (B) To enhance transcription elongation by stabilizing RNA polymerase on the DNA template. (C) To promote the export of mRNA from the nucleus and increase its stability and translational efficiency. (D) To remove introns from pre-mRNA during RNA splicing. (E) To initiate translation by providing a binding site for ribosomes at the 5' end of the mRNA.

19. Which of the following statements about RNA splicing is correct? (A) RNA splicing removes exons and joins introns to produce mature mRNA in eukaryotic cells. (B) The spliceosome removes introns and adds a polyA. tail to the 5' end of the RNA molecule. (C) RNA splicing is a process exclusive to prokaryotes. (D) Alternative splicing allows a single gene to produce multiple protein isoforms. (E) Splicing occurs in the cytoplasm after transcription is complete.