30. Which of the following best describes the function or characteristic of colicins?
(A) Colicins are enzymes secreted by bacteria to degrade host DNA during infection.
(B) Colicins are antimicrobial proteins produced by bacteria to kill or inhibit closely related bacterial strains.
(C) Colicins are RNA molecules that regulate gene expression in bacterial populations.
(D) Colicins are structural proteins involved in the formation of bacterial pili during conjugation.
(E) Colicins are lipopolysaccharides that form part of the bacterial outer membrane.

26. Which statements inaccurately describe base pairing between codon and anticodon? (A) The first two bases in a codon determine coding specificity by forming strong Watson-Crick base pairs with the anticodon. (B) Isoaccepting tRNAs bind different amino acids but recognize the same codon. (C) Wobble occurs when the third base of a codon forms a non-Watson-Crick base pair with the anticodon. (D) Wobble allows the same aminoacyl-tRNA to pair with multiple codons. (E) The super-wobble hypothesis suggests that a single tRNA with U in the first anticodon position (5' position of the anticodon) can recognize codons ending in any of the four bases under certain conditions.

27. Which of the following antibiotics do NOT inhibit protein translation?(A) Puromycin(B) Thiostrepton(C) Penicillins(D) Chloramphenicol(E) Viomycin

28. The function of miRNA is based on inhibiting which of the following factors?(A) eIF1A(B) eIF2(C) eIF3(D) eIF4A(E) eIF4E

29. Which of the following is a primary function of the 3' UTR in eukaryoticmRNA?(A) Facilitating the initiation of transcription.(B) Determining the site of ribosome binding for translation initiation.(C) Regulating mRNA stability and translation efficiency.(D) Coding for signal peptides during protein synthesis.(E) Ensuring the proper splicing of introns from the pre-mRNA.

31. Which of the following correctly differentiates rolling circle replication from binary replication in DNA replication? (A) Rolling circle replication involves bidirectional replication, while binary replication occurs unidirectionally. (B) Rolling circle replication is primarily used in prokaryotic chromosomal replication, whereas binary replication is exclusive to plasmid DNA. (C) Rolling circle replication generates single-stranded intermediates, while binary replication replicates both DNA strands simultaneously. (D) Rolling circle replication is initiated at multiple origins of replication, whereas binary replication starts at a single origin. (E) Rolling circle replication requires Okazaki fragments, while binary replication does not.

32.Which enzyme is commonly added when using a single restriction enzymein cloning, and what is its purpose?(A) T4 DNA polymerase, to fill in 5' overhangs and generate blunt ends toincrease ligation efficiency.(B) Reverse transcriptase, to synthesize cDNA from RNA prior to cloning.(C) Exonuclease, to degrade the unwanted DNA after restriction enzymedigestion.(D) Alkaline phosphatase, to prevent the vector from self-ligating by removing5' phosphate groups.(E) Topoisomerase, to relieve supercoiling in the DNA fragment during cloning.

33. Which of the following statements about PCR is incorrect? (A) Quantitative PCR can directly quantify the relative concentration of mRNA. (B) The use of 95°C during the reaction process is to cause DNA denaturation. (C) The temperature setting for the annealing step will affect the specificity of the product. (D) The use of 72°C during the reaction process is for polymerization, and the time must be adjusted based on the product size. (E) The discovery of Taq DNA polymerase, which can withstand high temperatures, is the key to PCR technology.

34. Integration of Lamda phage into host genome is mediated by a process called:(A) Cut-and-paste transposition(B) Replicative transposition(C) Homologous recombination(D) Non-homologous end-joining(E) Site-specific mutagenesis

35. In addition to the Transposase Gene, what is the most important component of DNA transposons? (A) Inverted Repeats (B) Long Terminal Repeats (C) Direct Repeats (D) Internal Resolution Site (E) Resolvase Gene

1. The opposite meaning of “increase” is:(A) Expand(B) Rise(C) Decrease(D) Grow