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प्रश्न
How are proteins classified on the basis of molecular shapes?
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उत्तर
On the basis of molecular shape, proteins are classified into two types—fibrous proteins and globular proteins.
- Fibrous proteins:- They are insoluble in water, long, thread-like and tend to lie side by side to form fibres. The polypeptide chains are held together by hydrogen bonds. Examples: Collagen in tendons; keratin in hair, skin, nails, horn and feathers; myosin in muscle; fibroin in silk
- Globular proteins:- They are soluble in water and aqueous solutions of bases, acids and salts. They are folded to form a spherical shape, have intramolecular hydrogen bonding and have weak intermolecular forces as compared to fibrous proteins.
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संबंधित प्रश्न
What is peptide linkage?
How is tripeptide formed?
Discuss the optical activity of lactic acid.
Define the following as related to proteins:
Peptide linkage
What type of bonding helps in stabilising the α-helix structure of proteins?
Write one difference between α-helix and β-pleated structures of proteins.
Differentiate between the following :
Peptide linkage and Glycosidic linkage
Which functional group participates in disulphide bond formation in proteins?
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:
Dinucleotide is obtained by joining two nucleotides together by phosphodiester linkage. Between which carbon atoms of pentose sugars of nucleotides are these linkages present?
Optical rotations of some compounds along with their structures are given below which of them have D configuration.
| (I) |  |
| (II) |  |
| (III) |  |
In fibrous proteins, polypeptide chains are held together by:
(i) van der Waals forces
(ii) disulphide linkage
(iii) electrostatic forces of attraction
(iv) hydrogen bonds
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?
Protein found in a biological system with a unique three-dimensional structure and biological activity is called a native protein. When a protein in its native form, is subjected to a physical change like change in temperature or a chemical change like, change in pH, denaturation of protein takes place. Explain the cause.
Which moieties of nucleosides are involved in the formation of phosphodiester linkages present in dinucleotides? What does the word diester in the name of linkage indicate? Which acid is involved in the formation of this linkage?
Explain the terms primary and secondary structure of proteins. What is the difference between α-helix and β-pleated sheet structure of proteins?
Peptide linkage is:
Explain formation of peptide linkage in protein with an example.
Given below are two statements labelled as Assertion (A) and Reason (R).
Assertion (A): Proteins are found to have two different types of secondary structures viz alpha-helix and beta-pleated sheet structure.
Reason (R): The secondary structure of proteins is stabilized by hydrogen bonding.
Select the most appropriate answer from the options given below:
Out of the following, which type of interaction is responsible for the stabilisation of the α-helix structure of proteins?
Proteins are polymers of ______.
What is the effect of denaturation on the structure of proteins?
Write a classification of proteins with an example.
