Module 3

Last update by Andy on 10/24/2013
187985 People have viewed this Quiz
  • Share

What is the difference between positive and negative control? What is the difference between inducible and repressible operons?

Answer:
In positive control, the regulatory protein is an activator. In negative control, it is a repressor. In inducible operons, transcription is never taking place and must be turned on. In repressible operons, transcription always takes place and must be turned off.

View Module 3 as Flashcard Deck

Related Quiz Content
  • shaw na wa
    Answered in Module 3
    Define RNA silencing (or interference). Explain how siRNAs arise and how they potentially affect gene expression. How are siRNAs different from the antisense RNA mechanism?
    Process in which cleavage of double-stranded RNA produces small interfering RNAs (siRNAs) that bind to mRNAs containing complementary sequences and bring about their cleavage and degradation. siRNAs are produced by the cleavage and processing of double-stranded RNA. antisense RNA are small RNA molecule that base pairs with a complementary DNA or RNA sequence and affects its functioning.
  • shaw na wa
    Answered in Module 3
    List at least three different types of DNA repair and briefly explain how each is carried out.
    mismatch repair - enzymes cut out the distorted section of the newly syntehsized strand and fill the gap with new nucleotides
    base-excision repair - a modified base is first excised and then the entire nucleotide is repaired
    direct repair - changes altered nucleotides into original correct structures
  • shaw na wa
    Answered in Module 3
    Frameshift mutations are caused by the __________ or __________ of one or more nucleotides in DNA.
    removal, insertion
  • shaw na wa
    Answered in Module 3
    What symbols are used to describe constitutive mutations in
    the lac operon?
    lacOc
  • shaw na wa
    Answered in Module 3
    What human condition is caused by unrepaired UV-induced lesions?
    Xeroderma pigmentosum (XP)
  • shaw na wa
    Answered in Module 3
    The general term for a protein that binds to an operator.
    repressor
  • shaw na wa
    Answered in Module 3
    These are factors that need not be adjacent to the genes they control. An example would be the lac operon’s repressor protein.
    trans
  • shaw na wa
    Answered in Module 3
    A catabolite-activating protein (CAP) exerts _____________control over the lac operon.
    positive
  • shaw na wa
    Answered in Module 3
    The __________ is a type of _________ protein that binds to a region of DNA in the promoter of a gene called the _________ and prevents ______________ from taking place.
    repressor, regulator, operator, transcription
  • shaw na wa
    Answered in Module 3
    The ____________________ consists of modifications to histone proteins that affect the expression of DNA sequences.
    histone code
  • shaw na wa
    Answered in Module 3
    This structure forms when an extra X chromosome is methylated and largely inactivated. It is most commonly found in females.
    Barr body