Skip to main content
Indietro

Microbiology Module 3 Study Guide

I pulsanti di controllo sono stati cambiati in modalità "navigazione".
1/31

Termini in questo insieme (31)

  • What is the central dogma of molecular biology?

    The flow of genetic material from DNA to RNA to protein.

  • How does RNA structurally differ from DNA?

    RNA has a ribose sugar, uses uracil instead of thymine, and is usually single-stranded.

  • What are the structural features of DNA and RNA nucleotides?

    Both have a sugar, phosphate group, and nitrogenous base; DNA has deoxyribose, RNA has ribose.

  • What is the role of DNA gyrase in replication?

    DNA gyrase relieves supercoiling ahead of the replication fork by cutting and rejoining DNA strands.

  • What does helicase do during DNA replication?

    Helicase unwinds and separates the two DNA strands at the replication fork.

  • What is the function of DNA polymerase III?

    DNA polymerase III synthesizes the new DNA strand by adding nucleotides in the 5' to 3' direction.

  • What role does DNA polymerase I play in replication?

    DNA polymerase I removes RNA primers and replaces them with DNA nucleotides.

  • What is the function of primase in DNA replication?

    Primase synthesizes short RNA primers to provide a starting point for DNA polymerase.

  • What does DNA ligase do during replication?

    DNA ligase joins Okazaki fragments by forming phosphodiester bonds to complete the lagging strand.

  • How does DNA directionality affect replication?

    DNA strands are antiparallel; replication is continuous on the leading strand and discontinuous on the lagging strand.

  • What are Okazaki fragments?

    Short DNA fragments synthesized on the lagging strand during discontinuous replication.

  • Define semi-conservative replication.

    Each new DNA molecule contains one original strand and one newly synthesized strand.

  • What is the replication fork?

    The Y-shaped region where DNA strands separate and replication occurs.

  • Describe the process of transcription in prokaryotes.

    RNA polymerase synthesizes mRNA from DNA template starting at the promoter.

  • What roles do rRNA, mRNA, and tRNA play in translation?

    rRNA forms ribosomes, mRNA carries the code, and tRNA brings amino acids.

  • What is the difference between codons and anticodons?

    Codons are mRNA triplets; anticodons are complementary tRNA triplets.

  • How does protein synthesis differ between prokaryotes and eukaryotes?

    Prokaryotes have coupled transcription and translation; eukaryotes have introns and exons and separate these processes.

  • What are introns and exons?

    Introns are non-coding sequences removed from mRNA; exons are coding sequences joined together.

  • What is an operon and why do bacteria use them?

    An operon is a gene cluster controlled by one promoter; it allows coordinated regulation of related genes.

  • Compare inducible and repressible operons.

    Inducible operons are off until activated; repressible operons are on until deactivated.

  • What is reverse transcription and which microbe uses it?

    Reverse transcription converts RNA to DNA; used by retroviruses like HIV.

  • How do mutations contribute to evolution?

    Mutations introduce genetic variation that can be acted on by natural selection.

  • How do base analogs and UV light cause mutations?

    Base analogs mimic bases causing mispairing; UV light causes thymine dimers disrupting DNA replication.

  • Define deletion, insertion, frameshift, silent, nonsense, and missense mutations.

    Deletion/insertion: add/remove bases; frameshift: shifts reading frame; silent: no amino acid change; nonsense: stop codon; missense: amino acid change.

  • What is the Ames test used for?

    To detect mutagenic potential of chemicals by observing mutations in bacteria.

  • What is excision repair?

    A DNA repair process that removes damaged bases and replaces them to prevent mutations.

  • Define genetic recombination.

    The exchange of genetic material between organisms leading to genetic diversity.

  • How does bacterial conjugation contribute to genetic diversity?

    Conjugation transfers plasmids between bacteria, spreading genes like antibiotic resistance.

  • What did Griffith's experiment demonstrate?

    Transformation: bacteria can take up genetic material from dead cells and gain new traits.

  • How does generalized transduction lead to genetic variation?

    Bacteriophages transfer random bacterial DNA between cells during infection.

  • What are plasmids and why are they important?

    Small circular DNA molecules that carry genes beneficial for survival and are used in genetic engineering.