1.6 Proteins


This is my mind map: '1.6 Proteins'. Its is based on the AQA A-Level Biology specification, and it is also based on the AQA Biology A -Level 2nd edition textbook. Find my matching 'Proteins' Flashcards on my profile, or follow the link here: https://www.goconqr.com/en-GB/p/4819880
Bee Brittain
Mind Map by Bee Brittain, updated more than 1 year ago
Bee Brittain
Created by Bee Brittain over 8 years ago

Resource summary

1.6 Proteins
  1. Amino Acids
    1. 20 Different A.A's in Protein
      1. Occur in all living organisms - evidence for evolution
      2. Constituents: - Variable R group - Central C atom - Amino Group (NH2) - Carboxylic Acid Group (COOH)
        1. Amino Acid Monomers combine to make dipeptides!
          1. Condensation Reaction
            1. Water molecule made from -OH of carboxylic acid group and -H from amino group of another amino acid
              1. The monomers are joined by a PEPTIDE BOND between the carbon atom of one amino acid and the nitrogen atom of the other
                1. Can be broken through a Hydrolysis reaction
              2. If many join together to make long chains, it is called POLYMERISATION. This makes a polypeptide
              3. Protein Structure
                1. Primary
                  1. - A specific sequence of amino acids - A single polypeptide chain
                  2. Secondary
                    1. Hydrogen Bonds form between different amino acids
                      1. Polypeptide chain twisted into 3D structure
                        1. Alpha Helix
                          1. Beta Pleated Sheet
                        2. Tertiary
                          1. The Helix/Beta pleated sheet is now folded even more. This means a more complex, yet SPECIFIC shape.
                            1. Disulphide Bridges - Fairly strong
                              1. Hydrogen Bonds - Weak but there are many
                                1. Ionic - Formed between any carboxyl and amino acid groups that ARE NOT involved forming peptide bonds. Weaker than disulphide bonds and easily broken by changes in pH
                                2. Quarternary
                                  1. Has a combination of MORE THAN ONE polypeptide chain
                                    1. Can be associated with non-protein (prosthetic) groups into large, complex protein molecules such as heamoglobin
                                  2. Test for Proteins
                                    1. Biuret Test
                                      1. Detects Peptide Bonds
                                      2. Add sodium hydroxide solution to solution that is to be tested
                                        1. Add a few drops of very dilute Copper (II) Sulphate solution and mix
                                          1. Goes purple = peptide bonds present = protein!
                                      3. Fibrous Proteins
                                        1. Long chains that run parallel
                                          1. Chains linked by cross-bridges
                                          2. Secondary structure is very tightly wound
                                            1. Teritary structure is wound into helix
                                              1. Quaternary is made of many of these, which are tightly wound into a 'rope'
                                            2. Glycine helps close package of lots of A.A
                                              1. Collagen
                                                1. STRUCTURAL FUNCTIONS
                                                  1. Insoluble
                                                  2. Globular Proteins
                                                    1. METABOLIC FUNCTIONS
                                                      1. Enzymes
                                                        1. Heamoglobin
                                                        2. Folded Structure
                                                          1. Soluble
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