MEDIUM
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Define essential and non-essential amino acids?

Important Questions on Biomolecules

MEDIUM
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
EASY
Write one point of difference between essential and non-essential amino acids.
EASY
Which one of the following statements is wrong?
EASY
Which one of the pairs of amino acids contains two chiral centres?
EASY
What are essential and non-essential amino acids? Give one example of each type. 
EASY
Among the following, identify the zwitterionic form
HARD
Among the following, an essential amino acid is
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
MEDIUM
The amino acid without chiral carbon is:
EASY
What are non-essential amino acids?
EASY
Which one of the following amino acids is least likely to be in the core of a protein?
EASY
Among the following, the essential amino acid is:
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.
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
Which of the following is the least likely to be involved in stabilizing the three-dimensional folding of most proteins?
EASY
How many different proteins consisting of 100 amino acids can be formed from 20 different amino acids?
MEDIUM
Protein is very essential for the growth, development and maintenance of living systems. Proteins are natural polymer of α-amino acids. A definite sequence of amino acids form a specific protein. Two or more than two amino acids bind to give peptide bond. Proteins are polypeptide, which loses its biological activity by physical or chemical changes.
Explain essential and non-essential amino acid with example.
 
EASY
Define the following with an example of each: Essential amino acids.
MEDIUM
Which of the following amino acids is NOT involved in gluconeogenesis?