Question

A scientist observes an enzyme polypeptide chain arranged in spiral turns that rise upward and are held in place by hydrogen bonds. Which level of structural arrangement is s/he looking at?

Answer 1

1. primary structure of proteins - amino acid sequence (peptide bonds)
2. secondary structure of proteins - alpha helix / beta sheets (hydrogen bonds)
3. tertiary structure of proteins - 3d structure ie how different alpha helix and beta sheets present in a protein come together to give rise to 3d structure which is responsible for the protein to function (disulphide bonds)
4. quaternary structure - this is observed in the case of multi -subunit proteins. Each subunit of the multi-subunit protein has its own 3d structure but for it to function it must combine with the other subunits in the multi-subunit protein.(non covalent interactions like hydrophobic interactions and Van der waals interactions ).

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