Level 1 — RecognitionBiomolecules — Carbohydrates & Lipids

Biomolecules — Carbohydrates & Lipids

⏱ 20 minutes30 marksprintable — key stays hidden on paper

Chapter: Biomolecules — Carbohydrates & Lipids

Level 1 — Recognition

Time Limit: 20 minutes Total Marks: 30

Section A — Multiple Choice (choose ONE correct answer) [1 mark each, 10 marks]

Q1. The chemical elements found in ALL carbohydrates are:

(a) C, H, O, N
(b) C, H, O
(c) C, H, O, P
(d) C, H, N, S

Q2. Which of the following is a monosaccharide?

(a) Sucrose
(b) Starch
(c) Fructose
(d) Cellulose

Q3. The bond formed between two monosaccharides during dehydration synthesis is called a:

(a) peptide bond
(b) glycosidic bond
(c) ester bond
(d) hydrogen bond

Q4. During hydrolysis, which molecule is added to split a polymer?

(a) Carbon dioxide
(b) Oxygen
(c) Water
(d) Glucose

Q5. The storage polysaccharide found in animals is:

(a) starch
(b) cellulose
(c) glycogen
(d) chitin

Q6. A triglyceride is composed of:

(a) glycerol + 3 fatty acids
(b) glycerol + 2 fatty acids + phosphate
(c) 3 glycerol + 1 fatty acid
(d) 4 fatty acids

Q7. An unsaturated fatty acid is characterised by:

(a) only single bonds between carbons
(b) one or more C=C double bonds
(c) a phosphate head
(d) a ring structure

Q8. Which lipid has an amphipathic (both hydrophilic and hydrophobic) nature?

(a) triglyceride
(b) wax
(c) phospholipid
(d) cholesterol

Q9. Cholesterol belongs to which class of lipids?

(a) triglycerides
(b) phospholipids
(c) steroids
(d) waxes

Q10. Chitin is the structural polysaccharide found in:

(a) plant cell walls
(b) fungal cell walls and arthropod exoskeletons
(c) bacterial capsules
(d) mammalian liver

Section B — Matching [5 marks]

Q11. Match each molecule in Column X with its correct description in Column Y. Write the letter next to the number. [5 marks, 1 each]

Column X	Column Y
(i) Glucose	(A) Structural polysaccharide of plant cell walls
(ii) Cellulose	(B) Waterproof coating on leaves/feathers
(iii) Phospholipid	(C) A monosaccharide, main energy sugar
(iv) Wax	(D) Major component of cell membranes
(v) Glycogen	(E) Storage polysaccharide in liver and muscle

Section C — True/False WITH Justification [3 marks each, 15 marks]

State True or False (1 mark) and give a one-sentence justification (2 marks).

Q12. Starch and cellulose are both polymers of glucose but differ in function because of their glycosidic bond orientation.

Q13. Saturated fatty acids are usually liquid at room temperature while unsaturated fatty acids are solid.

Q14. Dehydration synthesis releases a water molecule each time two monomers are joined.

Q15. Steroids have the same basic structure as triglycerides.

Q16. Lipids function in energy storage, insulation, and cell signalling.

Answer keyMark scheme & solutions

Section A — MCQ (1 mark each)

Q1. (b) C, H, O — Carbohydrates have a general formula $(CH_2O)_n$ ; only carbon, hydrogen and oxygen. (N/P are absent.)

Q2. (c) Fructose — a single sugar unit; sucrose is a disaccharide, starch/cellulose are polysaccharides.

Q3. (b) glycosidic bond — the covalent bond between sugar units. Peptide = proteins, ester = fats.

Q4. (c) Water — hydrolysis literally means "splitting with water."

Q5. (c) glycogen — animal storage polysaccharide; starch is plant storage.

Q6. (a) glycerol + 3 fatty acids — "tri" = three fatty acids esterified to one glycerol.

Q7. (b) one or more C=C double bonds — double bonds create kinks; saturated = all single bonds.

Q8. (c) phospholipid — polar phosphate head (hydrophilic) + fatty acid tails (hydrophobic).

Q9. (c) steroids — four fused carbon rings; cholesterol is the classic example.

Q10. (b) fungal cell walls and arthropod exoskeletons — chitin is a nitrogen-containing polysaccharide.

Section A total: 10 marks

Section B — Matching (1 mark each)

Q11.

(i) Glucose → (C) monosaccharide, main energy sugar
(ii) Cellulose → (A) structural polysaccharide of plant cell walls
(iii) Phospholipid → (D) major component of cell membranes
(iv) Wax → (B) waterproof coating on leaves/feathers
(v) Glycogen → (E) storage polysaccharide in liver and muscle

Section B total: 5 marks

Section C — True/False with Justification (3 marks each)

Q12. TRUE (1) — Both are glucose polymers, but starch has α-glycosidic bonds (digestible, coiled) whereas cellulose has β-glycosidic bonds (straight, rigid, indigestible to humans). (2)

Q13. FALSE (1) — It is the reverse: saturated fatty acids pack tightly and are usually solid at room temperature, while unsaturated (kinked) fatty acids are usually liquid (oils). (2)

Q14. TRUE (1) — Dehydration (condensation) synthesis forms a covalent bond and removes one molecule of water per bond formed. (2)

Q15. FALSE (1) — Steroids consist of four fused carbon rings, whereas triglycerides consist of glycerol + three fatty acids; their structures are entirely different. (2)

Q16. TRUE (1) — Lipids store energy (triglycerides), provide insulation (subcutaneous fat) and act as signalling molecules (steroid hormones). (2)

Section C total: 15 marks

Paper total: 30 marks

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  {"claim": "Section A has 10 MCQs worth 1 mark each = 10 marks", "code": "mcq = 10*1\nresult = (mcq == 10)"},
  {"claim": "Total paper marks equal 30", "code": "sectionA = 10*1\nsectionB = 5*1\nsectionC = 5*3\ntotal = sectionA + sectionB + sectionC\nresult = (total == 30)"},
  {"claim": "A triglyceride uses 1 glycerol and 3 fatty acids (Q6 correct answer count)", "code": "glycerol = 1\nfatty_acids = 3\nresult = (glycerol == 1 and fatty_acids == 3)"},
  {"claim": "Section C contributes 15 marks (5 questions x 3)", "code": "result = (5*3 == 15)"}
]