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Beta Strand quiz

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  • What is the general conformation of a beta strand in protein secondary structure?
    A beta strand adopts an extended zigzag conformation that is periodic and repeats every two amino acid residues.
  • How do the R groups orient themselves in a beta strand?
    The R groups alternate orientation, zigzagging up and down along the strand.
  • What is the rise per amino acid residue in a beta strand?
    The rise is 3.5 angstroms per amino acid residue in a beta strand.
  • How does the rise of a beta strand compare to that of an alpha helix?
    The rise of a beta strand (3.5 Å) is more than double that of an alpha helix (1.5 Å).
  • What is the pitch of a beta strand and what does it represent?
    The pitch of a beta strand is 7 angstroms, representing the periodic repeat distance every two residues.
  • How are beta strands typically depicted in diagrams?
    Beta strands are depicted as broad arrows pointing toward the C-terminal end of the protein.
  • In which direction do the arrows representing beta strands point?
    The arrows point toward the C-terminal end of the protein.
  • How are hydrogen bonds oriented in beta sheets compared to the direction of the strands?
    Hydrogen bonds in beta sheets are oriented perpendicular to the direction of the beta strands.
  • How do you calculate the length of a beta strand?
    Multiply the number of amino acid residues by the rise (3.5 Å) to get the length.
  • What is the length of a beta strand with 5 amino acid residues?
    The length is 17.5 angstroms (5 residues × 3.5 Å per residue).
  • How does the length of a 5-residue beta strand compare to a 5-residue alpha helix?
    A 5-residue beta strand is 17.5 Å long, while a 5-residue alpha helix is only 7.5 Å long, making the beta strand much more extended.
  • What is the main structural difference between beta strands and alpha helices?
    Beta strands are much more extended, while alpha helices are more coiled.
  • What stabilizes beta sheets formed by beta strands?
    Beta sheets are stabilized by hydrogen bonds between the peptide backbones of adjacent strands.
  • How often does the periodic structure of a beta strand repeat?
    The periodic structure repeats every two amino acid residues.
  • What is a key visual difference between a single beta strand and two connected beta strands in diagrams?
    A single beta strand is shown as one arrow, while two connected beta strands are shown as two arrows joined together, both pointing toward their C-terminal ends.