🦠 Microbiology Solved MCQs with Answers

Practice 1927 approved 🦠 Microbiology questions with verified answers from the 🧬 Medical Science subject for Pakistan exams.

1927 solved MCQs

Which is not an essential part of a two-component phosphorelay system?Answer: Response regulator The DNA that actually codes for a protein's primary structure in eukaryotes isAnswer: portions of the gene called exons Stem and loop structures areAnswer: structures in DNA caused by inverted repeats Both strands of DNA serve as templates concurrently inAnswer: replication Proofreading activity to maintain the fidelity of DNA synthesisAnswer: is a function of the 3'-5' exonuclease activity of the DNA polymerases Which of the following repairs nicked DNA by forming a phosphodiester bond between adjacent nucleotides?Answer: DNA ligase The enzyme that catalyzes the synthesis of DNA is calledAnswer: DNA polymerase Which of the following possesses both 5'-3' and 3'-5' exonuclease activity?Answer: Kornberg enzyme Which of the following statements on replication in E.coli is correct?Answer: It occurs in bidirectional manner The replication of chromosomes by eukaryotes occurs in a relatively short period of time becauseAnswer: each chromosome contains multiple replicons In E.coli, which enzyme synthesizes the RNA primer for Okazaki fragments?Answer: DnaG During which of the following process a new copy of a DNA molecule is precisely synthesized?Answer: Replication DNA gyrase is inhibited byAnswer: nalidixic acid Which of the following enzymes unwind short stretches of DNA helix immediately ahead of a replication fork?Answer: Helicases During DNA replication in prokaryotes, synthesis begins on the circular chromosomeAnswer: always at the same place DNA replication rates in prokaryotes are approximately of the order ofAnswer: 1,000 bases per second Which of the following lacks 3'-5' exonuclease activity?Answer: All of the above The synthesis of DNA by DNA polymerase occurs in theAnswer: 5' to 3' direction Which of the following enzyme is used for synthesis of RNA under the direction of DNA?Answer: RNA polymerase What is the usual sequence of a Pribnow box?Answer: TATAAT Which of the following component of RNA polymerase facilitates the recognition of promoter sequences?Answer: s subunit Which of the following statement defines a replicon?Answer: A DNA molecule that is able to replicate and be maintained Which eukaryotic RNA polymerase makes tRNA's?Answer: RNA polymerase 3 The location of first hexameric sequence typically found in pro-karyotic promoters isAnswer: approximately 35 bases upstream of the transcription start site Which of the following is a product of transcription?Answer: all of these The sigma factorAnswer: recognizes the promotor The synthesis of mRNA based on a DNA template is calledAnswer: transcription Recognition/binding site of RNA polymerase is calledAnswer: promoter Which of the following enzyme(s) is/are required for lactose fermentation?Answer: All of these Which of these catalyzes the synthesis of RNA from a DNA template?Answer: RNA polymerase