MEDIUM
Earn 100

Choose the CORRECT combination of statements given below related to cysteine residue in proteins.

i. Cysteine can be linked to tyrosine by S-O bond.

ii. Cysteine can be linked to another cysteine by S-S bond.

iii. Cysteine can complex with Zn2+.

iv. Cysteine can be linked to methionine by S-S bond

50% studentsanswered this correctly

Important Questions on Biomolecules

EASY
Which of the following is the least likely to be involved in stabilizing the three-dimensional folding of most proteins?
HARD

A small viral peptide can insert its 6 amino acids (represented as a barrel) into the lipid bilayer as depicted in the figure given below.Question Image

The table depicts the different properties of amino acids.

  Properties
Polar and uncharged Polar and charged Non-polar and hydrophobic
Amino acids Gly Asp Ala
Ser Glu Val
Thr Lys Leu
Cys Arg Ile
Asn His Pro
Gln - Met
Tyr - Phe
- - Trp
EASY
How many different proteins consisting of 100 amino acids can be formed from 20 different amino acids?
EASY
Which one of the following is the most abundant protein in the animals?
EASY
Among the following, identify the zwitterionic form
HARD
Which one of the following techniques is used for the detection of proteins?
HARD
Three given polypeptides (P,Q and R), of same size and same pI(7.2), have a single aspartic acid in each of them. In polypeptide P, the aspartic acid residue is on the surface. In polypeptide Q, it is surrounded by negatively charged residues, whereas in polypeptide R it is deeply buried in a hydrophobic core. pKa of the side chain carboxylate of free (in solution) aspartic acid is 3.65. The polypeptides are in a buffer of pH 7.4. The change in pKa of the aspartic acid side chain carboxylate in the polypeptides P, Q and R is likely to
EASY
Amino acid analysis of two globular protein samples yielded identical composition per mole. Which one of the following characteristics is necessarily identical for the two proteins?
EASY
Which one of the pairs of amino acids contains two chiral centres?
EASY
Which one of the following amino acids is least likely to be in the core of a protein?
MEDIUM

Match the following

(a) Inhibitor of catalytic activity (i) Ricin
(b) Possess peptide bonds (ii) Malonate
(c) Cell wall material in fungi (iii) Chitin
(d) Secondary metabolite (iv) Collagen

Choose the correct option from the following

EASY
Which one of the following statements is wrong?
EASY
Identify the basic amino acid from the following.
HARD
The activity of a certain protein is dependent on its phosphorylation. A mutation in its gene changed a single amino acid which affected the function of the molecule. Which amino acid change is most likely to account for this observation?
MEDIUM
In primary structure of protein, the protein thread showed helix with four amino acids S-C-Y-E and a naphthalene structure in amino acid Y. In such condition what will be the direction of helix and what are the positions of amino acids
MEDIUM
Match the compounds of Column I with their functions in Column II.
  Column -I   Column -II
1 Trypsin p Fights infectious agents
2 GLUT-4 q Is an intercellular ground substance
3 Collagen r Works as an enzyme
4 Antibody s Enables glucose transport into cells
EASY
Which ONE of the following is likely to occur upon heating a solution of eukaryotic protein from 20°C to 95°C?
MEDIUM
If the acidic, basic and hydrophobic residues of proteins are considered to be red, green and blue in colour, respectively, then a globular protein in aqueous solution would have
EASY
Identify the statement which is incorrect.
MEDIUM
Which of the following amino acids is NOT involved in gluconeogenesis?