Proteins

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Proteins

• Made of Carbon, Hydrogen, Oxygen, Nitrogen (and
  sometimes sulfur)
• Arranged from only 20 amino acids!!! (like the
  alphabet)

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Amino Acids

• Made up of 4 parts
• Part 1 Hydrogen atom
• Part 2 Amino group (NH2)
• Part 3 Acid group (COOH)
• Part 4 R group (side chains that differ from
  amino acid to amino acid)
• http//hyperphysics.phy-astr.gsu.edu/HBASE/organic
  /aminostruct.html

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Protein Structure

• 1 amino acid linked to another by a peptide bond
  (see drawing on board)
• Does this look familiar?????
• DEHYDRATION SYNTHESIS

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Protein Structure

• Many amino acids linked together are a
  polypeptide chain
• Chain folds up on itself to form a giant ball
  (like a mess of yarn) which forms the protein
• There are four levels of protein structure

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Protein Structure

• Primary Level
• Polypeptide chain- like fruit frenzy on a string

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Protein Structure

• Secondary Level
• Chain coils around (like a spring)
• Called the alpha helix

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Protein Structure

• Tertiary Level
• Coil becomes folded up

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Protein Structure

• Quaternary Level
• Multiple chains join together

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PROTEINS

• Most diverse group of biological molecules

• Enzymes
• Structural
• Transport
• Nutritious
• Regulatory
• Defense
• Function depends on structure

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Enzymes- a special kind of protein

• Special proteins - increase chemical rxn rates
  called catalysts
• Most biological rxns cant take place without them

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How Enzymes Work

• Energy needed to start a reaction
• Called ACTIVATION ENERGY
• Enzymes lower this

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How Enzymes Work

• Enzymes help rxns occur at normal cell temps
• Weaken chemical bonds
• Heat does too- but heat not good for cells

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How Enzymes work

• Enzymes are specific- each helps only 1 reaction
  occur
• Whats involved?
• Substrate- what the enzyme acts on
• Active site- where the substrate fits perfectly
  in to the enzyme
• Like pieces of a puzzle

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An enzyme at work