AQA A-Level Biology – Proteins Latest 2023

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AQA A-Level Biology – Proteins Latest 2023 Amino Acid ✔✔A monomer that will join with other amino acids to form a protein Dipeptide ✔✔Two amino acids bonded together via a peptide bond P ... olypeptide ✔✔Many amino acids bonded together via peptide bonds Protein ✔✔A combination of polypeptides Amine Group ✔✔-NH2, a basic group where the amino part of amino acid comes from Carboxyl Group ✔✔-COOH, an acidic group where the acid part of amino acid comes from R Group ✔✔A side group that can be comprised of different chemical groups Condensation Reaction ✔✔The reaction that allows the formation of a peptide bond Process of a Condensation Reaction ✔✔A H+ is removed from the amine group, and the OH- is removed from the carboxyl group on the other amino acid. This forms water and a dipeptide. Primary Structure ✔✔The linear amino acid sequence of the polypeptide chain Secondary Structure ✔✔The arrangement of the primary structure when considering hydrogen bonds. This forms either an alpha helix or a beta pleated sheet Alpha Helix ✔✔A helix shape that can be formed when considering a polypeptide's secondary structure Beta Pleated Sheet ✔✔A bent v-shaped structure that can be formed when considering a polypeptide's secondary structure Tertiary Structure ✔✔The overall 3D shape of the polypeptide chain, considering all types of bonds; hydrogen bonds, ionic bonds and disulphide bridges. This results in a compact structure Quarternary Structure ✔✔The 3D shape of multiple polypeptide chains combined into one complex molecule. This also considers external associated non-proteins Prosthetic Groups ✔✔Associated non-proteins which affect the quarternary structure of a protein Biuret Test ✔✔The test to see if a protein is present Process of the Biuret Test ✔✔Add 2cm^3 of the sample with an equal volume of sodium hydroxide. Add a few drops of very dilute copper(II) sulphate (0.05%) and mix. A positive test turns purple, a negative test remains blue. Fibrous Proteins ✔✔Serve a structural function Globular Proteins ✔✔Carry out a metabolic function Primary Structure of Collagen ✔✔An unbranched polypeptide chain Secondary Structure of Collagen ✔✔Very tightly wound, an alpha helix Tertiary Structure of Collagen ✔✔Winds into another large helix Quarternary Structure of Collagen ✔✔Made up of three polypeptide chains with the same tertiary structure, wound together in a rope shape Uses of Collagen ✔✔In hair, as part of tendons Collagen's protein type ✔✔Fibrous protein [Show More]

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