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प्रश्न
Proteins are found to have two different types of secondary structures viz. α-helix and β-pleated sheet structure. α-helix structure of protein is stabilised by:
पर्याय
Peptide bonds
van der Waals forces
Hydrogen bonds
Dipole-dipole interactions
उत्तर
Hydrogen bonds
Explanation:
These structures arise due to the regular folding of the backbone of the polypeptide chain due to hydrogen bonding between > C – O and N – H – group of the peptide bond.
α-helix is one of the most common ways in which a polypeptide chain forms all possible hydrogen bonds by twisting into a right-handed screw (helix) with the –NH group of each amino acid residue hydrogen-bonded to > C = O of an adjacent turn of helix.
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संबंधित प्रश्न
Discuss the optical activity of lactic acid.
What type of bonding helps in stabilising the ∝-helix structure of proteins?
Differentiate between the following :
Fibrous proteins and Globular proteins
Write one difference between α-helix and β-pleated structures of proteins.
Which of the following are purine bases?
(i) Guanine
(ii) Adenine
(iii) Thymine
(iv) Uracil
α-Helix is a secondary structure of proteins formed by twisting of polypeptide chain into right-handed screw like structures. Which type of interactions are responsible for making the α-helix structure stable?
Structures of glycine and alanine are given below. Show the peptide linkage in glycylalanine.
\[\ce{\underset{(Glycine)}{H2N - CH2 - COOH}}\];
\[\begin{array}{cc}
\ce{H2N - CH2 - COOH}\\
|\phantom{......}\\
\ce{\underset{(Alanine)}{CH3}\phantom{...}}
\end{array}\]
Assertion: β-glycosidic linkage is present in maltose,
Reason: Maltose is composed of two glucose units in which C–1 of one glucose unit is linked to C–4 of another glucose unit.
Presence of disulphide link gives rise to which structure of protein?
Assertion (A): Proteins are polymers of α-amino acids connected by a peptide bond.
Reason (R): A tetrapeptide contains 4 amino acids linked by 4 peptide bonds.
