Learn English 100% free...Get 1 free lesson per week // Add a new lesson
Log in!

Click here to log in
New account
Millions of accounts created on our sites.
JOIN our free club and learn English now!

  • Home
  • Print
  • Guestbook
  • Report a bug

  • Get a free English lesson every week!
    Click here!

    - Our other sites

    Learn English > English lessons and exercises > English test #111247: SDS-PAGE
    > Other English exercises on the same topic: Diseases [Change theme]
    > Similar tests: - Health problems - Idioms; human body - Vocabulary: I'm hungry - At the hospital - Vocabulary: Emergency-First aid... - Vocabulary, The sun: a friend or an enemy - Vocabulary: vegetables are good for you - Vocabulary: we’re freezing!
    > Double-click on words you don't understand


    Sodium-dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) is an analytical technique widely used to study proteins.

    A mixture of proteins is exposed to SDS which is an anionic detergent. In the presence of the detergent, proteins are denatured and lose their secondary and tertiary structures. They look like ropes the length of which depends on the number of amino acids of the primary structure of the proteins.

    SDS also loads all the proteins with negative charges and, when submitted to an electrical field, the charged proteins migrate to the anode.

    In conclusion the proteins present in the mixture only diverge with respect to their molecular weight, not to their charge.

    The gel used to perform the electrophoresis is made of long chains of polyacrylamide which have been cross-linked by bisacrylamide. The ratio between bisacrylamide and acrylamide used determines the size of the pores of the gel. During the synthesis of the gel, this ratio is not constant but increases, which explains why the pores of the gel become narrower. The gel has been formed in such a way that during their migration towards the anode, the proteins have to pass through the denser part of the gel and, finally are stopped by pores narrower than their size. The bands seen after staining of the gels correspond to population of proteins with similar molecular weight.


    Twitter Share
    English exercise "SDS-PAGE" created by anonyme with The test builder.
    Click here to see the current stats of this English test

    Please log in to save your progress.

    1. SDS-PAGE stands for Sodium-dodecylsulfate polyacrylamide gel .

    2. Sodium-dodecylsulfate is an anionic .

    3. When exposed to SDS the proteins only differ by their .

    4. The length of the denatured proteins is related to their number of .

    5. In the presence of SDS all the proteins are charged.

    6. In the presence of an field, proteins migrate to the anode.

    7. The gel is formed by chains of polyacrylamide with bisacrylamide.

    8. During their migration towards the anode, the proteins have to pass through pores.

    9. At the end of the experiment the gel is .

    10. The proteins of similar molecular weight appear as stained .

    End of the free exercise to learn English: SDS-PAGE
    A free English exercise to learn English.
    Other English exercises on the same topic : Diseases | All our lessons and exercises