Q 21 :

Which is not true for arginine?           [2023]

• It has a fairly high melting point.

   

• It has high solubility in benzene.

   

• It is associated with more than one pKa values.

   

• It is a crystalline solid.

   

Q 22 :

Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R.

Assertion A: A solution of the product obtained by heating a mole of glycine with a mole of chlorine in presence of red phosphorous generates chiral carbon atom.

Reason R: A molecule with 2 chiral carbons is always optically active.

In the light of the above statements, choose the correct answer from the options given below:               [2023]

• Both A and R are true but R is NOT the correct explanation of A.

   

• A is true but R is false

   

• A is false but R is true

   

• Both A and R are true and R is the correct explanation of A.

   

Q 23 :

Total number of tripeptides possible by mixing of valine and proline is ________.      [2023]

Q 24 :

A short peptide on complete hydrolysis produces 3 moles of glycine (G), two moles of leucine (L) and two moles of valine (V) per mole of peptide. The number of peptide linkages in it are ________.              [2023]

Q 25 :

In an oligopeptide named alanylglycylphenyl alanylisoleucine, the number of $s{p}^2$ hybridised carbons is ________.    [2023]

Q 26 :

Identify the correct statements.

A. Arginine and Tryptophan are essential amino acids.
B. Histidine does not contain heterocyclic ring in its structure.
C. Proline is a six membered cyclic ring amino acid.
D. Glycine does not have chiral centre.
E. Cysteine has characteristic feature of side chain as $MeS-C{H}_2-C{H}_2-.$

Choose the correct answer from the options given below :    [2026]

• C and D Only

   

• A and D Only

   

• B and E Only

   

• C and E Only

   

Q 27 :

The number of possible tripeptides formed involving alanine (ala), glycine (gly) and valine (val), where no amino acid has been used more than once is:         [2026]

• 3

   

• 4

   

• 8

   

• 6

   

Q 28 :

The correct statements are :

A. Activation energy for enzyme catalysed hydrolysis of sucrose is lower than that of acid catalysed hydrolysis.

B. During denaturation, secondary and tertiary structures of a protein are destroyed but primary structure remains intact.

C. Nucleotides are joined together by glycosidic linkage between $C₁ and C₄$ carbons of the pentose sugar.

D. Quaternary structure of proteins represents overall folding of the polypeptide chain.

Choose the correct answer from the options given below :         [2026]

• A, B and D Only

   

• B and C Only

   

• A, C and D Only

   

• A and B Only

   

Q 29 :

In the given pentapeptide, find out an essential amino acid (Y) and the sequence present in the pentapeptide:

Choose the correct answer from the options given below:  [2026]

• (Y) Threonine  (Sequence) Thr–Ser–Asp–Gly–Ala

   

• (Y) Serine    (Sequence) Ser–Asp–Thr–Ala–Gly

   

• (Y) Serine    (Sequence) Thr–Ser–Asp–Ala–Gly

   

• (Y) Threonine  (Sequence) Ser–Thr–Asp–Gly–Ala