PROTEINS

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  • Created by: Kyle Ford
  • Created on: 23-02-18 09:26

PROTEINS

MADE FROM LONG CHAINS - OF AMINO ACIDS (MONOMER)

- DIPEPTIDE = 2 AMINO ACIDS
- POLYPEPTIDE = 2+ AMINO ACIDS

- PROTEINS = 1/+ POLYPEPTIDES

DIFFERENT AMINO ACIDS - DIFFERENT VARIABLE GROUPS

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CONDENSATION REACTIONS

AMINO ACIDS - CONDENSATION REACTION - FORM POLYPEPTIDES

MOLECULE OF WATER = RELEASED

BOND = POLYPEPTIDE BOND

DIGESTION - HYDROLYSE POLYPEPTIDES

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PROTEIN STRUCTURE

PRIMARY

- SEQUENCE OF AMINO ACIDS - IN POLYPEPTIDE CHAIN

SECONDARY

- HYDROGEN BONDS - FORM BETWEEN AMINO ACIDS
- CAUSE CHAIN TO COIL
- EITHER ALPHA HELIX - OR - FOLDED BETA PLEATED SHEAT

TERTIARY

- FUTHER COIL/FOLD
- MORE BONDS FORM DIFFERENT PARTS - HYDROGEN AND IONIC BONDS
- DISULFIDE BRIDGES - BETWEEN AMINO ACID CYSTEINE - COME CLOSE TOGETHER
- SULFUR ATOM - ONE CYSTEINE - BOND TO ANOTHER
- PROTEINS - SINGLE POLYPEPTIDE CHAIN - TETIARY STRUCTURE - FINAL 3D

QUATERNARY

- SEVERAL POLYPEPTIDE CHAINS
- HELD TOGETHER BY BONDS
- PROTEINS - 1+ POLYPEPTIDE CHAIN - FINAL 3D STRUCTURE

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PROTEIN FUNCTION

ENZYMES

- USUALLY SPHERICAL - DUE TO TIGHT FOLD OF POLYPEPTIDE CHAINS
- SOLUBLE - ROLES IN METABOLISM
- SOME INVOLVED IN BREAKDOWN AND OTHERS IN SYNTHESIS

ANTIBODIES

- IMMUNE RESPONSE
- 2 LIGHT AND 2 HEAVY POLYPEPTIDE CHAINS - BONDED
- ANTIBODIES - VARIABLE REGIONS - AMINO ACIDS VARY IN THESE REGIONS

TRANSPORT PROTEINS

- E.G - CHANNEL PROTEINS - CELL MEMBRANE
- CHANNEL PROTEINS - HYDROPHOBIC AND HYDROPHILLIC AMINO ACIDS
- CAUSE PROTEIN TO FOLD - FORM CHANNEL
- TRANSPORT MOLECULES AND IONS - ACROSS MEMBRANE

STRUCTURAL PROTEINS

- STRONG
- LONG POLYPEPTIDE CHAINS - PARALLEL - CROSS LINKS
- E.G. KERATIN (NAILS AND HAIR) - COLLAGEN (CONNEC. TISSUE)

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BIURET TEST

TEST FOR PROTEINS

- SOLUTION NEEDS TO BE ALKALINE
- ADD SODIUM HYDROXIDE SOLUTION

- ADD COPPER (II) SULFATE SOLUTION

- POSITIVE = BLUE - PURPLE
- NEGATIVE = REMAIN BLUE

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