Biomolecules — Class 11 Biology NCERT Solutions (Free)
Free step-by-step NCERT solutions for Class 11 Biology chapter "Biomolecules" — 7 important questions with detailed answers for CBSE board exam preparation.
✓ 100% Free
✓ No Login Needed
✓ NCERT / CBSE Aligned
✓ Download as PDF
TL;DR: Free step-by-step NCERT solutions for Class 11 Biology chapter "Biomolecules" — 7 important questions with detailed answers for CBSE board exam prepar…
Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated
🤖 Stuck on any question? Ask Syllab's free AI Tutor for a step-by-step explanation — instant, unlimited, no login.
Key Questions Covered:
- Define carbohydrates and classify them with examples.
- What are proteins? Describe the structure of amino acids and peptide bonds.
- Explain the levels of protein structure with examples.
- Define lipids and describe the structure and functions of triglycerides.
- Describe the structure and functions of nucleic acids (DNA and RNA).
- Explain the structure of cellulose and its importance in plant cell walls.
- + 1 more questions in the full chapter
Solutions Summary:
| Question | Status |
|---|---|
| Define carbohydrates and classify them with examples. | ✓ Solved |
| What are proteins? Describe the structure of amino acids … | ✓ Solved |
| Explain the levels of protein structure with examples. | ✓ Solved |
| Define lipids and describe the structure and functions of… | ✓ Solved |
| Describe the structure and functions of nucleic acids (DN… | ✓ Solved |
| Explain the structure of cellulose and its importance in … | ✓ Solved |
Showing 6 of 7 questions
Q1: Define carbohydrates and classify them with examples.
Carbohydrates are organic compounds composed of carbon, hydrogen, and oxygen in the ratio Cx(H2O)y. They are primarily synthesized by photosynthetic organisms and serve as energy sources and structural components.
Classification:
1. Monosaccharides (simple sugars; 3-7 carbons):
- Trioses (3C): Glyceraldehyde, dihydroxyacetone.
- Pentoses (5C): Ribose, deoxyribose, ribulose (in photosynthesis).
- Hexoses (6C): Glucose, fructose, galactose.
- Function: Energy metabolism; components of nucleic ac...
Q2: What are proteins? Describe the structure of amino acids and peptide bonds.
Proteins are polymers of amino acids; they are fundamental molecules performing diverse functions: enzyme catalysis, structural support, transport, immunity, regulation. Amino acid structure:
All amino acids have:
1. Carboxyl group (-COOH): Acidic group; donates proton.
2. Amino group (-NH2): Basic group; accepts proton.
3. Hydrogen atom (-H).
4. Radical group (R group or side chain): Variable structure distinguishing different amino acids.
5. Central carbon (alpha carbon): Bonds all four group...
Q3: Explain the levels of protein structure with examples.
Protein structure has four hierarchical levels:
1. Primary structure:
- Linear sequence of amino acids in polypeptide chain.
- Held by peptide bonds.
- Example: Insulin has 51 amino acids in specific sequence.
- Determines all higher levels of structure; small changes (mutations) can drastically affect function.
2. Secondary structure:
- Repetitive, local folding caused by hydrogen bonds between backbone atoms (not R groups).
- Common structures:
a) α-helix: Coiled structure; found in kerat...
Q4: Define lipids and describe the structure and functions of triglycerides.
Lipids are a diverse group of hydrophobic (nonpolar) or amphipathic molecules composed primarily of carbon, hydrogen, and some oxygen. They are poorly soluble in water but soluble in nonpolar solvents.
Triglycerides (triacylglycerols, fats and oils):
Structure:
- Composed of glycerol (3-carbon alcohol with 3 hydroxyl groups) + 3 fatty acids.
- Each fatty acid is a long hydrocarbon chain (14-18 carbons typically) with a carboxyl group at one end.
- Fatty acids joined to glycerol via ester bonds...
Q5: Describe the structure and functions of nucleic acids (DNA and RNA).
Nucleic acids are polymers of nucleotides; they store and express genetic information. Structure:
Nucleotide components:
1. Nitrogenous base (purine or pyrimidine):
- Purines (2 rings): Adenine (A), Guanine (G).
- Pyrimidines (1 ring): Cytosine (C), Thymine (T), Uracil (U).
2. Five-carbon sugar: Ribose (RNA) or Deoxyribose (DNA; lacks oxygen at 2' position).
3. Phosphate group: Connects sugars of adjacent nucleotides.
DNA (Deoxyribonucleic acid):
- Double helix structure (discovered by W...
Q6: Explain the structure of cellulose and its importance in plant cell walls.
Cellulose is a structural polysaccharide composed of glucose units linked by β-1,4-glycosidic bonds. Structure:
1. Monomer unit: β-glucose (differs from α-glucose in configuration at C1 carbon).
2. Polymer chain:
- Linear, unbranched polymer of β-glucose.
- Thousands of glucose units per molecule.
- Forms long, rigid fibers due to extended conformation.
- Polymer length determines mechanical properties.
3. Hydrogen bonding:
- Hydrogen bonds form between hydroxyl groups of adjacent glucose uni...
Showing 6 of 7 questions. Visit the full page for complete solutions.
More Class 11 Biology NCERT Solutions
- Animal Kingdom — Class 11 Biology NCERT Solutions
- Plant Kingdom — Class 11 Biology NCERT Solutions
- Morphology of Flowering Plants — Class 11 Biology NCERT Solutions
- Anatomy of Flowering Plants — Class 11 Biology NCERT Solutions
- Cell the Unit of Life — Class 11 Biology NCERT Solutions
- Cell Cycle and Cell Division — Class 11 Biology NCERT Solutions
- Photosynthesis in Higher Plants — Class 11 Biology NCERT Solutions
- Respiration in Plants — Class 11 Biology NCERT Solutions
- Breathing and Exchange of Gases — Class 11 Biology NCERT Solutions
- Body Fluids and Circulation — Class 11 Biology NCERT Solutions
- Excretory Products and Their Elimination — Class 11 Biology NCERT Solutions
- Neural Control and Coordination — Class 11 Biology NCERT Solutions
- Chemical Coordination and Integration — Class 11 Biology NCERT Solutions