Chapter U2.21, Problem 2E

Interpretation Introduction

Interpretation : Protein is to be described.

Concept Introduction : Our body is made of many types of molecules. There are body building molecules called amino acids. Amino acids join together to form large molecules called proteins. The receptor sites in our nose are also made of proteins.

Answer to Problem 2E

Proteins are the building blocks of our body including organs, muscles and hair.

Proteins are macromolecules formed from long chains of amino acids. The carboxyl group of one amino acid link with the amine group of another amino acid to form a peptide or an amide bond. In the process a molecule of water is expelled.

Explanation of Solution

Proteins are the building blocks of our body including organs, muscles and hair. Important features of proteins are:

1. The amino acids link with each other to form peptide bonds. The carboxyl group of one amino acid link with the amine group of another amino acid to form a peptide bond. In this way long chain of amino acids is formed called protein. Amino acids can be linked in a variety of manner so a variety of protein molecules are available.
2. During the formation of peptide bond, two hydrogen atoms and an oxygen atom break off from the amino acids and form a water molecule.
3. Proteins are large molecules, hence called macromolecules.
4. As chains of amino acids are formed, it twists and bends causing the chains to fold.
5. The R groups on amino acids determine the structure of proteins. The hydrophobic R groups tend to cluster in the middle of the molecule while the hydrophilic R groups tend to be on eth outside of the molecule.
6. Smell receptor sites are protein molecules that have pockets that fit to a particular smell molecule. When the smell molecule attaches to the pocket, it changes the structure of the protein a little. This change triggers the neighboring protein molecule which sends signal to the brain.

Conclusion

Proteins are building blocks of our body such as organs, hair and muscles.They are essential in all living organisms. They help in fighting off infections by helping the immune system.