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General Biology: Protein and Nucleic Acid Structure and Function

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Terms in this set (20)

  • What are the main functions of proteins in cells?
    Functions include: catalysis (enzymes), defense (antibodies), movement, signaling, structure, and transport.
  • What is the role of enzymes in biological reactions?
    Enzymes are catalysts that speed up reactions without being consumed, binding specific substrates at their active sites.
  • Why is protein folding important?
    Folding creates a stable 3D structure necessary for protein function; unfolded proteins are nonfunctional.
  • What are molecular chaperones?
    Proteins that assist other proteins in folding correctly to achieve functional conformations.
  • What are prions and why are they significant?
    Prions are misfolded proteins that can induce normal proteins to misfold, causing infectious diseases.
  • Describe the central dogma of molecular biology.
    Information flows from DNA to mRNA (transcription) and then from mRNA to protein (translation).
  • What are the three components of a nucleotide?
    A 5-carbon sugar, a phosphate group, and a nitrogenous base.
  • How do DNA and RNA sugars differ?
    DNA contains deoxyribose (lacking an oxygen at 2′ carbon), RNA contains ribose (with OH at 2′ carbon).
  • What nitrogenous bases are found in DNA and RNA?
    DNA has A, T, G, C; RNA has A, U, G, C (uracil replaces thymine).
  • How are nucleotides polymerized into nucleic acids?
    By phosphodiester linkages formed via condensation between the 3′ hydroxyl of one nucleotide and 5′ phosphate of another.
  • What is the directionality of nucleic acid strands?
    Strands have a 5′ to 3′ direction, with an unlinked 5′ phosphate at one end and 3′ hydroxyl at the other.
  • Describe the primary structure of DNA and RNA.
    The linear sequence of nucleotides that encodes genetic information.
  • What is the secondary structure of DNA?
    Two antiparallel strands twisted into a double helix stabilized by complementary base pairing.
  • Which bases pair together in DNA?
    Adenine pairs with Thymine and Guanine pairs with Cytosine via hydrogen bonds.
  • What is the tertiary structure of DNA?
    DNA supercoils and wraps around histone proteins forming chromatin, compacting DNA inside the nucleus.
  • How does RNA secondary structure differ from DNA?
    RNA folds into hairpins and loops with base pairing within the same strand, forming diverse 3D shapes.
  • What makes RNA versatile compared to DNA?
    RNA can store information, self-replicate, and catalyze reactions (ribozymes).
  • What is the RNA World Hypothesis?
    Proposes that RNA was the first self-replicating molecule and precursor to life.
  • Why is the sugar-phosphate backbone important in nucleic acids?
    It provides structural support and directionality for the sequence of bases.
  • What is a condensation reaction in nucleic acid polymerization?
    A reaction where monomers join and release water to form phosphodiester bonds.