Feedback for Multiple Choice Quiz 20b

  1. The key here is that SDS binds to and denatures proteins to form negatively charged particles of roughly equal charge:mass; hence they separate based soley on mass.

  2. At pH = 7, histone are positively charged and myoglobin is negatively charged.

  3. SDS-PAGE yields the monomer Mr; gel filtration yields the native Mr. Both are required to determine the quaternary structure.

  4. Equivalently: "Larger proteins enter the beads less readily and smaller proteins elute last", i.e. each follows from the other.

  5. These four statements are also an explanation for the the correct answer to question 9.
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  Incorrect answers have the "red-lit" button next to your choice.