Question 1

What are amino acids? Write the correct reaction for formation of peptide bond between amino acids.

Accepted Answer

\alpha-  amino acids are derivatives of carboxylic acids obtained by replacing  \alpha-  hydrogen by amino group. An example is glycine  H_2N-CH_2-COOH .Formation of peptide bond: H_2N-CH_2-COOH+H_2N-CH_2-COOH \xrightarrow {\Delta} H_2N-CH_2 - \underset {   \underset {\displaystyle O}{||}  }{C} -    \underset {   \underset {\displaystyle H}{|}  }{N} - CH_2-COOH+H_2O \displaystyle - \underset {   \underset {\displaystyle O}{||}  }{C} -    \underset {   \underset {\displaystyle H}{|}  }{N} -   is the peptide bond.

Question 2

Give an example ofi) Globular proteins.ii) Naturally occurring optically inactive amino acid.

Accepted Answer

i) Albumin, insulin, haemoglobin and thyroglobulin are globular proteins.ii) Glycine ( H_2N-CH_2-COOH ) is naturally occurring optically inactive amino acid.

Question 3

(i) Deficiency of which vitamin causes scurvy?(ii) What type of linkage is responsible for the formation of proteins?(iii) Write the product formed when glucose is treated with  HI .

Accepted Answer

(i) Vitamin C(ii) Peptide linkage(iii) On prolonged heating with HI, glucose gives n-hexane. C_6H_{12}O_6 \xrightarrow{HI} CH_3CH_2CH_2CH_2CH_2CH_3

Biomolecules