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The Structure of Proteins. Functions of Proteins. Fibrous proteins – structural, e.g. collagen. Globular proteins – metabolic functions, e.g. haemoglobin. It is their structure that allows them to carry out their functions . . Structure of Proteins.
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Functions of Proteins • Fibrous proteins – structural, e.g. collagen. • Globular proteins – metabolic functions, e.g. haemoglobin. • It is their structure that allows them to carry out their functions.
Structure of Proteins • Monomer units of proteins are called amino acids.
Structure of Proteins Amino Acids C
Structure of Proteins Amino Acids AMINO GROUP H C N H
Structure of Proteins Amino Acids AMINO GROUP O H H C C N O H CARBOXYLGROUP
Structure of Proteins Amino Acids AMINO GROUP O H H C C N O H CARBOXYL GROUP
H Structure of Proteins Amino Acids AMINO GROUP O H H C C N O H CARBOXYL GROUP
Structure of Proteins Amino Acids H AMINO GROUP O H H C C N O H CARBOXYL GROUP
Structure of Proteins Amino Acids H AMINO GROUP O H H C C N O H CARBOXYL GROUP R-GROUP (Variant)
Structure of Proteins Amino Acids H AMINO GROUP O H H C C N O H CARBOXYL GROUP R-GROUP (Variant)
Structure of Proteins PRIMARY STRCUTURE – Polypeptides • Polypeptides are composed of amino acids bonded to each other, like beads on a string • The bond that holds them together is called a peptide bond • They are formed by loss of water so is called a condensation reaction.
Structure of Proteins PRIMARY STRCUTURE – Polypeptides
Structure of Proteins PRIMARY STRCUTURE – Polypeptides • -OH from carboxyl group • -H from amino group • Forms peptide bond
Structure of Proteins Secondary Structure – α helix +ve -ve
Structure of Proteins Tertiary Structure – α helix • 3D structure is formed by further bonds, depending on the function • Disulphide bonds – strong and not easily broken down • Ionic bonds – easily broken down by changes in pH (carobxy/amino groups) • Hydrogen bonds – numerous be very easily broken down
Functions of Proteins • Fibrous proteins – structural, e.g. collagen. • Globular proteins – metabolic functions, e.g. haemoglobin. • It is their structure that allows them to carry out their functions. • i.e. the 3D structure is v.v.v important in carrying out it’s function • Makes proteins distinctive – interacting with other molecules
Structure of Proteins Quaternary Structure • Complex molecules containing many polypeptide chains
Structure of Proteins Example – haemoglobin: