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Bio Help

  1. Nov 8, 2004 #1
    Bio Help!!

    what is the difference between amino acids on thier own and amino acids that have been incorporated into a polypeptide chain?

    My answer is that amino acids on their on do nothing. However when they interact they create a protein which eventually takes on a particular function.

    why does boiling an egg cause it to harden?
    why does it require both a detergent and a reducing agent to dissolve the hard boiled white.

  2. jcsd
  3. Nov 9, 2004 #2
    polypeptide chains are amnio acids joined together in one lon chain there r several diff:
    presence of peptide bonds
    diff function

    an egg hardens when boiled because the heat destroys most of the bonds holding the protein structure togther hence causes aggluntination of the proteins...
    pardon any mistakes cos i jus woke up...
  4. Nov 9, 2004 #3


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    Gold Member

    On the contrary, individual amino acids are pretty important. They are present in and around sites of DNA/RNA synthesis, because they are needed in order to build the nucleotides that form those molecules. It is also believed that they were integral parts to the formation of organic molecules, and therefore life itself.

    The coiling of proteins is very specific. If there is one thing about the function of proteins that matters, it is shape. Small changes in pH or temperature change the shape of the protein by breaking peptide bonds between amino acids, and render the protein useless. In the case of an egg, the proteins are denatured by heat to the point where they form a solid.
  5. Nov 11, 2004 #4
    Amino acids by themselves exist in the body as zwitterions. They have at least 2 charges groups, the alpha NH3+ group, and the alpha COO- group. Some amino acids have ionizable side chains that carry charges depending on the pH of the buffer they are in. When amino acids are incorporated into a polypeptide chain, all the NH3+ and COO- groups become involved in peptide bonds and the only ionizable alpha COO- and NH3+ groups are found at the C-terminal and N-terminal respectively. The side chains however, are not involved in peptide bonds and are still ionizable, sticking out of the peptide bonded chain. The properties of these side chains confer stability to the folded protein (hydrophobic interactions, sulfide linkages), or can link multiple polypeptide chains together (sulfide linkages).

    Amino acids by themselves are quite important. Some amino acids help your body (like detoxification, increase metabolism) while others are quite harmful. An example of a harmful amino acid in the body is the notorious homocysteine that is believed to contribute to increased risk of cardiovascular disease.
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