Classify proteins with suitable examples.

1. 1 · Open in two lines. Proteins are large molecules made of amino acids joined by peptide bonds. They are classified by shape, composition, function and nutritional value.
2. 2 · Draw a classification chart. [Chart: Proteins → simple / conjugated / derived, with each sub-class branching out]
3. 3 · By shape. Fibrous (collagen, keratin) and globular (albumin, haemoglobin, enzymes).
4. 4 · By composition.
   • Simple: albumins, globulins, glutelins, prolamines, scleroproteins, histones.
   • Conjugated: glyco-, lipo-, phospho-, chromo-, metallo- and nucleoproteins.
   • Derived: primary (coagulated proteins) and secondary (proteoses, peptones, peptides).
5. 5 · By function and nutritional quality.
   • Function: enzymes, structural, transport, hormones, defence, storage, contractile.
   • Nutrition: complete, partially incomplete, incomplete.
6. 6 · Significance. Classification tells us where a protein is found, how it behaves on heating and how well it supports growth.
7. 7 · Nutrition link. Cereal–pulse combinations and a little milk or egg turn partially incomplete proteins into a high-quality mix.
8. 8 · Close in one line. One protein can fit several classes: haemoglobin is globular, a chromoprotein and a transport protein.

Scoring tip: Use tables with two examples per class. A neat chart and correct examples score more than long definitions.