Question 1

Cheilosis and digestive disorders are due to deficiency of

Accepted Answer

Deficiency of riboflavin (vitamin B _2) can cause cheilosis and digestive disorder.

Question 2

A tetrapeptide is made of naturally occuring alanine, serine, glycine and valine. If the C-terminal amino acid is alanine and N -terminal amino acid is chiral, the number of possible sequence of the t

Accepted Answer

Since glycine (gly) is achiral, alanine (Ala) is the C-terminal amino acid, therefore N -terminal amino acid can be valine (val) or serine (ser). In the view of these condition, the following four sequences for the tetrapeptide is possible. (i) Val-gly-Ser-Ala (ii) Val-Ser-gly-Ala (iii) Ser-gly-Val-Ala (iv) Ser-Val-gly-Ala

Question 3

Which one of the following is a water soluble vitamin, that is not excreted easily?

Accepted Answer

B group vitamins and vitamin C are soluble in water except vitamin B _ 12 all are excreted easily.

Question 4

Glycosidic linkage between C_1 of -glucose and C_2 of -fructose is found in

Accepted Answer

- Maltose is composed of two glucose units. - Sucrose has glycosidic linkage between C _1 of -glucose and C_2 of -fructose. - Lactose is composed of galactose and glucose - Amylose has glycosidic linkage between C_1 of -glucose C_4 of -glucose.

Question 5

The naturally occurring amino acid that contains only one basic functional group in its chemical structure is

Accepted Answer

Asparagine has only one basic functional group in its chemical structure. Others are basic amino acid with more than one basic functional group.

Question 6

Thiamine and pyridoxine are also known respectively as :

Accepted Answer

Vitamin B_1 - Thiamin Vitamin B _6 - Pyridoxine

Question 7

The helical structure of protein is stabilized by

Accepted Answer

The -helix structure is formed when the chain of -amino acids coils as a right handed screw (called -helix) because of the formation of hydrogen bonds between amide groups of the same peptide chain, i.e., NH group in one unit is linked to carbonyl oxygen of the third unit by hydrogen bonding. This hydrogen bonding between different units is responsible for holding helix in a position.

Question 8

Glucose reacts with X number of molecules of phenyl hydrazine to yield osazone. The value of X is,

Accepted Answer

Hence, three molecules of phenyl hydrazine ( C _6 H _5 NHNH _2 ) is used to yield osazone.

Question 9

Which of the following acts as an antioxidant in edible oils?

Accepted Answer

Vitamin E is an antioxidant present in edible oils.

Question 10

An organic compound with the formula C _ 6 H _ 12 O _ 6 forms a yellow crystalline solid with phenylhydrazine and gives a mixture of sorbitol and mannitol when reduced with sodium. Which among the fol

Accepted Answer

Since the compound forms a yellow crystalline solid, i.e. osazone with phenylhydrazine, it may be an aldohexose or a ketohexose. Further, since on reduction, compound forms a mixture of sorbitol and mannitol, it must be a ketohexose, i.e. fructose. Recall that glucose on reduction gives only one alcohol glucitol (Sorbitol)

Question 11

Compounds I and II may be grouped as

Accepted Answer

When structures I and II are C -2 epimers, it implies that these are epimers and diastereomers too.

Biomolecules — Previous Year Questions & Solutions