Question

You have seen that most students are able to memorize the levels of structure in a protein--primary, secondary, tertiary, and quaternary. The question now becomes how to aid the students in visualizing and understanding that the sequence of amino acids will impart ionic or hydrogen bonding that will induce curves (alpha-helix) or folds (beta-sheets) in the amino acid chain. These curves and folds will be able to interact amongst each other and give the polypeptide (which is part of a protein or maybe the entire protein being made) a three-dimensional shape that will enable the polypeptide to bind to another polypeptide and form a complete protein. Rank the following groups in the order that they contribute to the structure of a protein. (Free amino acids to completed proteins).
1. Helix-sheet-turn-helix
2. Alpha-helix or beta-sheet
3. Polypeptide A joined to polypeptide B, which joins to polypeptide C
4. Amino acid sequence a-b-c-d-e

Answer 1

Answer:

Amino acid sequence a-b-c-d-e.

This is the simplest  units which forms monomers when linked together by the peptide bonds.Thus they form the foundation of protein primary structure

Alpha helix or beta helix.

The alpha helix forms the secondary structure of  protein ,They are held the primary structure in spiral shape.The shape is formed by the H-bond between  O of the CO of oneamino acid, and the H atom of NH- of another amino acid four places ahead.when the Hydrogen bonds become loose and joined ends to ends. they formed the beta-sheet.

Helix-sheet-turn Helix- this is made up of two helices held together by  short amino acids.This is the major binding unit of DNA.

Polypeptide A joins to Polypeptide B joins to polypeptide C. This for a macro-molecule of  Quaternary structure.They are held by  all the bonds- the disulphide bridges,hydrogen bonds, hyrophobic interactions and the ionic bonds.

Explanation: