CBSE Class 11 Biology Very Short Answer Questions: Biomolecules (NCERT-Based)

Course and Examination Framework

Course: CBSE Class 11 Biology

Board: Central Board of Secondary Education

Unit III: Cell Structure and Function

Chapter 9: Biomolecules

Question Type: Very Short Answer Questions (VSA)

Answer Length: 20–30 Words

Syllabus Compliance: Strictly as per NCERT

Examination Relevance: CBSE Class 11 Annual & School Examinations

Section A: Basic Concepts of Biomolecules (Questions 1–10)

Q1. What are biomolecules?
Ans: Biomolecules are organic chemical compounds found in living organisms that form cellular structures and regulate metabolic activities.

Q2. Name the major elements present in biomolecules.
Ans: Carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulphur are the major elements present in biomolecules.

Q3. What are micromolecules?
Ans: Micromolecules are low molecular weight compounds such as amino acids, sugars, nucleotides, and fatty acids found in cells.

Q4. What are macromolecules?
Ans: Macromolecules are high molecular weight compounds formed by polymerisation of micromolecules, such as proteins, polysaccharides, and nucleic acids.

Q5. Why is carbon called the backbone of biomolecules?
Ans: Carbon forms stable covalent bonds and long chains, allowing formation of complex organic molecules essential for life.

Q6. What is metabolism?
Ans: Metabolism is the sum total of all biochemical reactions occurring within a living cell or organism.

Q7. Define anabolism.
Ans: Anabolism consists of constructive metabolic reactions that synthesise complex molecules from simpler ones using energy.

Q8. Define catabolism.
Ans: Catabolism consists of destructive metabolic reactions that break down complex molecules to release energy.

Q9. Name two inorganic constituents of cells.
Ans: Water and mineral salts are important inorganic constituents of cells.

Q10. What is the living state?
Ans: The living state refers to continuous metabolic activity maintained within a cell or organism.

Section B: Carbohydrates (Questions 11–20)

Q11. What are carbohydrates?
Ans: Carbohydrates are organic compounds composed of carbon, hydrogen, and oxygen, usually in the ratio of 1:2:1.

Q12. Name the simplest carbohydrates.
Ans: Monosaccharides are the simplest carbohydrates and cannot be hydrolysed further.

Q13. Give one example of a monosaccharide.
Ans: Glucose is a common monosaccharide and a primary source of energy in cells.

Q14. What are oligosaccharides?
Ans: Oligosaccharides are carbohydrates formed by condensation of two to ten monosaccharide units.

Q15. Name one disaccharide.
Ans: Sucrose is a disaccharide composed of glucose and fructose.

Q16. What are polysaccharides?
Ans: Polysaccharides are complex carbohydrates formed by polymerisation of many monosaccharide units.

Q17. Name the storage carbohydrate in plants.
Ans: Starch is the main storage carbohydrate in plants.

Q18. Name the storage carbohydrate in animals.
Ans: Glycogen is the storage carbohydrate found in animals.

Q19. What is cellulose?
Ans: Cellulose is a structural polysaccharide forming the main component of the plant cell wall.

Q20. Why is cellulose insoluble in water?
Ans: Cellulose contains β-glycosidic bonds forming strong hydrogen bonding, making it insoluble in water.

Section C: Proteins (Questions 21–30)

Q21. What are proteins?
Ans: Proteins are polymers of amino acids linked by peptide bonds and perform structural, enzymatic, and regulatory functions.

Q22. What is an amino acid?
Ans: An amino acid is the basic structural unit of proteins containing an amino group, carboxyl group, hydrogen, and variable side chain.

Q23. How many standard amino acids occur in proteins?
Ans: Twenty standard amino acids are commonly found in proteins.

Q24. What is a peptide bond?
Ans: A peptide bond is a covalent bond formed between two amino acids during protein synthesis.

Q25. What is the primary structure of protein?
Ans: The primary structure refers to the linear sequence of amino acids in a polypeptide chain.

Q26. Name two secondary protein structures.
Ans: Alpha-helix and beta-pleated sheet are secondary structures of proteins.

Q27. What determines the function of a protein?
Ans: The specific three-dimensional folding or tertiary structure determines the function of a protein.

Q28. What is denaturation of proteins?
Ans: Denaturation is the loss of biological activity of proteins due to heat, pH change, or chemicals.

Q29. Name one structural protein.
Ans: Keratin is a structural protein found in hair, nails, and skin.

Q30. Name one transport protein.
Ans: Haemoglobin is a transport protein that carries oxygen in blood.

Section D: Lipids, Nucleic Acids, and Enzymes (Questions 31–50)

Q31. What are lipids?
Ans: Lipids are hydrophobic organic compounds insoluble in water but soluble in organic solvents.

Q32. Why are lipids not true polymers?
Ans: Lipids are not formed by repeated monomer units, unlike carbohydrates and proteins.

Q33. Name one simple lipid.
Ans: Fats are examples of simple lipids.

Q34. What are phospholipids?
Ans: Phospholipids are complex lipids that form the basic structure of biological membranes.

Q35. Name a steroid lipid.
Ans: Cholesterol is a steroid lipid.

Q36. What are nucleic acids?
Ans: Nucleic acids are polymers of nucleotides responsible for storage and expression of genetic information.

Q37. Name the two types of nucleic acids.
Ans: DNA and RNA are the two types of nucleic acids.

Q38. What is a nucleotide?
Ans: A nucleotide consists of a nitrogenous base, pentose sugar, and phosphate group.

Q39. State one function of DNA.
Ans: DNA stores and transmits hereditary genetic information.

Q40. Name one type of RNA.
Ans: Messenger RNA (mRNA) is a type of RNA involved in protein synthesis.

Q41. What are enzymes?
Ans: Enzymes are proteinaceous biological catalysts that speed up biochemical reactions without being consumed.

Q42. What is the active site of an enzyme?
Ans: The active site is the specific region of an enzyme where the substrate binds.

Q43. Name one factor affecting enzyme activity.
Ans: Temperature affects enzyme activity by influencing molecular movement and enzyme structure.

Q44. What is optimum temperature of enzymes in humans?
Ans: The optimum temperature for most human enzymes is around 37°C.

Q45. What is enzyme specificity?
Ans: Enzyme specificity refers to the ability of an enzyme to act on a specific substrate only.

Q46. Name one model explaining enzyme action.
Ans: The lock-and-key model explains enzyme–substrate interaction.

Q47. What is induced fit model?
Ans: The induced fit model states that enzyme changes shape to accommodate substrate binding.

Q48. What role do enzymes play in metabolism?
Ans: Enzymes regulate and accelerate metabolic reactions, maintaining cellular efficiency.

Q49. What are metabolic pathways?
Ans: Metabolic pathways are sequences of enzyme-controlled biochemical reactions in cells.

Q50. Why is metabolism considered a defining feature of life?
Ans: Continuous metabolic activity distinguishes living organisms from non-living systems.

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