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Anatomy
Question | Answer |
---|---|
1st structural levels of proteins | 1. primary structure- amino acids creating a polypeptide chain (beads) |
2nd structural levels of proteins | 2. secondary structure- when proteins twist or bend upon themselves -alpha helix = coils of a telephone cord -pleated sheets = held together by hydrogen bonds, different parts of the polypeptide chain fold back on themselves |
3rd structural level of proteins | tertiary- when the alpha helix or pleated sheets fold upon one another to form a compact globular molecule .maintained by hydrogen and covalent bonds |
4th structural level of proteins | quaternary- when two or more polypeptide chains combine to form a complex protein |
Fibrous proteins | extended and strandlike .tertiary or quaternary structure .insoluable in water .mechanical support and tensile strength .also known as structural proteins .keratin and collagen |
Globular Proteins | .compact spherical proteins .at least tertiary structure .water soluable, chemically active, play roles in biological processes .functional proteins .enzymes + antibodies |
Protein Denaturation | .when proteins lose three dimmensional shape .globular proteins .broken hydrogen bonds through increased changes in ph or temperature |
active sites | regions that fit and interact chemically with other molecules of similar shape and charge |
Molecular Chaperones | .help proteins maintain three dimmensional structure .quick and accurate folding .heat shock proteins |
Enzymes and Enzyme Activity | .enzymes= globular proteins that are biological catalyst |