Your cart is empty.
Practice each question, then open the answer or worked solution.
What are the common types of secondary structures of proteins?
Proteins mainly have two common secondary structures—α-helix and β-pleated sheet.
Solution coming soon.
What type of bonding helps in stabilizing the α-helix structure of proteins?
Answer: The α-helix structure in proteins is stabilized by hydrogen bonds between the -NH2 group of one amino acid and the -COOH group of another amino acid in nearby turns of the helix.
Differentiate between globular and fibrous proteins.
| Fibrous protein | Globular protein |
|---|---|
| It is a fibre-like structure formed by the polypeptide chain. They are held together by strong hydrogen and disulphide bond. | The polypeptide chain in this protein is folded around itself, which gives rise to a spherical structure. |
| Insoluble in water. | Soluble in water. |
| Used for structural purposes. For example, keratin is present in nails and hair; collagen is present in tendons, and myosin is present in muscles. | All enzymes along with some hormones such as insulin are globular proteins. |
Solution coming soon.
How do you explain the amphoteric behaviour of amino acids?
Amino acids act as both acids and bases due to carboxyl and amino groups, forming zwitterions.
Solution coming soon.
What are enzymes?
Answer: Enzymes are proteins that act as biological catalysts. They help speed up reactions inside living things, work on specific substrates, and their names usually end in '-ase' (e.g., maltase or oxidoreductase).
What is the effect of denaturation on the structure of proteins?
Denaturation disrupts the protein's structure except for the sequence of amino acids.
Solution coming soon.
How are vitamins classified? Name the vitamin responsible for the coagulation of blood.
Vitamins are classified by their solubility; vitamin K is needed for blood clotting.
Solution coming soon.
Why are vitamin A and vitamin C essential to us? Give their important sources.
Answer: Deficiency of vitamin A causes night blindness and eye problems; its sources include fish liver oil, carrots, butter, and milk. Lack of vitamin C leads to scurvy (bleeding gums); it is present in citrus fruits and green leafy vegetables.
What are nucleic acids? Mention their two important functions.
Nucleic acids are biomolecules in cell nuclei that store genetic information and help synthesize proteins.
Solution coming soon.
What is the difference between a nucleoside and a nucleotide?
Both are made from sugar and base, but nucleotides also have phosphoric acid.
Solution coming soon.