Skip to main content
Pearson+ LogoPearson+ Logo

Nucleic Acids 2 quiz #1 Flashcards

Back
Nucleic Acids 2 quiz #1
Control buttons has been changed to "navigation" mode.
1/10
  • What is the function of the enzyme helicase in nucleic acid metabolism?
    Helicase is an enzyme that unwinds and separates the two strands of the DNA double helix, allowing processes such as DNA replication and transcription to occur.
  • What type of bond connects nucleotide monomers in nucleic acid polymers?
    Nucleotide monomers are connected by phosphodiester bonds in nucleic acid polymers. These bonds link the 5' phosphate group of one nucleotide to the 3' hydroxyl group of the next.
  • How are the two strands of DNA oriented relative to each other?
    The two strands of DNA are oriented antiparallel to each other. This means one strand runs 5' to 3' while the other runs 3' to 5'.
  • What chemical group is found at the 5' end of a DNA strand?
    The 5' end of a DNA strand has a phosphate group attached to the 5' carbon of the pentose sugar. This distinguishes it from the 3' end, which has a hydroxyl group.
  • Why is DNA more stable than RNA under alkaline conditions?
    DNA is more stable than RNA because it lacks a reactive 2' hydroxyl group on its sugar. The 2' hydroxyl in RNA can react and cause strand cleavage at high pH.
  • At what wavelength do nucleic acids absorb light maximally?
    Nucleic acids absorb light maximally at 260 nanometers. This property helps distinguish them from proteins, which absorb maximally at 280 nanometers.
  • How does the number of hydrogen bonds differ between A-T and G-C base pairs?
    Adenine-thymine pairs form two hydrogen bonds, while guanine-cytosine pairs form three hydrogen bonds. This difference affects the melting temperature and stability of DNA regions.
  • What is the consequence of DNA always pairing purines with pyrimidines?
    Pairing purines with pyrimidines ensures that DNA has a consistent width throughout the double helix. This structural uniformity is crucial for proper genetic information storage.
  • If a double-stranded DNA sample contains 35% adenine, what percentage of thymine does it contain?
    If a DNA sample contains 35% adenine, it also contains 35% thymine. This is because adenine always pairs with thymine in double-stranded DNA.
  • What base does adenine pair with in RNA during gene expression?
    In RNA, adenine pairs with uracil during gene expression and transcription. This differs from DNA, where adenine pairs with thymine.