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Biomolecules

Biomolecules. Proteins. Proteins. Biomolecule Many structures = wide range of functions Greek word proteios meaning first place Account for more than 50% dry mass of cells. Protein Function. Instrumental in almost everything organisms do: Speed up chemical rxn Structural support

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Biomolecules

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  1. Biomolecules Proteins

  2. Proteins • Biomolecule • Many structures = wide range of functions • Greek word proteiosmeaning first place • Account for more than 50% dry mass of cells

  3. Protein Function Instrumental in almost everything organisms do: • Speed up chemical rxn • Structural support • Storage • Transport • Cellular communications • Movement • Foreign substance defense

  4. Enzymes • Most important type of protein • Regulate metabolism • Act as catalysts (chem agents that selectively speed up chemrxns in the cell w/out being consumed by the rxn) • “workhorses” that keep cells running by carrying out the processes of life

  5. Specific Structure = Specific function • A human has tens of thousands of different proteins, each w/a specific structure & function. • Most structurally sophisticated molecules known. • 3-D shape or conformation

  6. Polypeptide • Monomer = amino acid (aa) • 20 different aa (others exist) • Polymers of aa are called polypeptides • One or more polypeptides folded & coiled into a specific conformation = protein

  7. Amino Acid Monomers • Organic molecules • Functional groups • Carboxyl group (-COOH) • Amino group (-NH2) • Center contains an asymmetrical C atom called the alpha Carbon

  8. Name the four different partners of the alpha C.

  9. Amino Acid differences • R group (side chain) varies • Can be as simple as a H, or much larger (handout) • Physical & chemical properties of the R group determine the unique characteristics of the aa. • Polar (hydrophilic) vsnonpolar properties • Acidic (neg in charge, carboxyl group) • Basic aa have amino groups (+ in charge)

  10. Amino Acid Polymer Formation • Links formed between • Carboxyl group of one aa • Amino group of another aa • Enzyme causes them to form by catalyzing a dehydration rxn • Bond = Peptide bond • Polypeptide = a polymer of many aa linked by peptide bonds

  11. Peptide bond formation One end has a free amino group (N-terminus), the other end has a free carboxyl group (C-terminus). The polypeptide backbone has repeating sequence of atoms- side chains “stick out”

  12. Polypeptide formation

  13. Polypeptide

  14. Protein Conformation & Function • Yarn / Sweater analogy • Functional proteins are usually several polypeptides precisely twisted, folded, and coiled into a uniquely shaped molecule • Determined by the aa sequence

  15. Structure dictates Function • Function depends upon the ability to recognize & bind to some other molecule • Proteins like antibodies bind to particular foreign substances that invade the body • Proteins like Enzymes recognize & bind to its substrate

  16. Pharmaceuticals • Many drugs like morphine, heroin, & other opiate drugs mimic endorphins • Similar shape binds to specific receptor proteins (like a lock & key)

  17. Levels of Protein Structure: • Primary • Secondary • Tertiary • Quaternary

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