Page 1 of 64
AQA AS-LEVEL BIOLOGY PAPER 1 EXAM QUESTIONS AND CORRECT
ANSWERS LATEST EDITION 2026
AQA AS-LEVEL BIOLOGY PAPER 1
Questions with Answers and Rationales
SECTION 1: BIOLOGICAL MOLECULES
Questions 1–40
1. Which of the following is a monosaccharide?
• A) Sucrose
• B) Glucose
• C) Maltose
• D) Lactose
Answer: B) Glucose
Rationale: Glucose is a monosaccharide (single sugar unit). Sucrose, maltose, and lactose are
disaccharides made of two monosaccharide units.
2. The bond formed between two monosaccharides is a:
• A) Peptide bond
• B) Glycosidic bond
• C) Ester bond
• D) Hydrogen bond
Answer: B) Glycosidic bond
1|Page
,Page 2 of 64
Rationale: A condensation reaction between two monosaccharides forms a glycosidic bond,
releasing a water molecule.
3. Which test is used to detect the presence of starch?
• A) Benedict's test
• B) Iodine test
• C) Biuret test
• D) Emulsion test
Answer: B) Iodine test
Rationale: Iodine solution turns blue-black in the presence of starch.
4. A positive Benedict's test result is indicated by:
• A) Blue colour
• B) Brick-red precipitate
• C) Purple colour
• D) White emulsion
Answer: B) Brick-red precipitate
Rationale: Benedict's test detects reducing sugars; a brick-red precipitate forms on heating.
5. Which of the following is a reducing sugar?
• A) Sucrose
• B) Maltose
• C) Starch
• D) Cellulose
Answer: B) Maltose
Rationale: Maltose is a reducing sugar. Sucrose is a non-reducing sugar. Starch and cellulose are
polysaccharides.
2|Page
,Page 3 of 64
6. Sucrose is a non-reducing sugar. To test for sucrose, the sample must first be:
• A) Heated with Benedict's solution
• B) Boiled with dilute hydrochloric acid, then neutralised
• C) Mixed with iodine
• D) Mixed with ethanol
Answer: B) Boiled with dilute hydrochloric acid, then neutralised
Rationale: Acid hydrolysis breaks sucrose into glucose and fructose, which are reducing sugars.
7. The general formula of a monosaccharide is:
• A) (CH₂O)n
• B) CₙH₂ₙOₙ
• C) CₙH₂ₙ₊₂O
• D) CₙH₂ₙO₂
Answer: A) (CH₂O)n
Rationale: Monosaccharides have the general formula (CH₂O)n, where n is typically 3–7.
8. Which polysaccharide is found in plant cell walls?
• A) Starch
• B) Glycogen
• C) Cellulose
• D) Chitin
Answer: C) Cellulose
Rationale: Cellulose is the main structural polysaccharide in plant cell walls.
9. Which polysaccharide is the main storage carbohydrate in animals?
3|Page
, Page 4 of 64
• A) Starch
• B) Glycogen
• C) Cellulose
• D) Chitin
Answer: B) Glycogen
Rationale: Glycogen is the storage carbohydrate in animals, stored in liver and muscle cells.
10. Starch is a mixture of which two polysaccharides?
• A) Amylose and amylopectin
• B) Cellulose and chitin
• C) Glycogen and cellulose
• D) Amylose and glycogen
Answer: A) Amylose and amylopectin
Rationale: Starch consists of amylose (unbranched) and amylopectin (branched).
11. Which of the following is a function of lipids?
• A) Catalysis of reactions
• B) Energy storage and insulation
• C) Genetic information storage
• D) Oxygen transport
Answer: B) Energy storage and insulation
Rationale: Lipids store energy, provide insulation, and form cell membranes.
12. A triglyceride is formed from:
• A) One glycerol and one fatty acid
• B) One glycerol and three fatty acids
4|Page
AQA AS-LEVEL BIOLOGY PAPER 1 EXAM QUESTIONS AND CORRECT
ANSWERS LATEST EDITION 2026
AQA AS-LEVEL BIOLOGY PAPER 1
Questions with Answers and Rationales
SECTION 1: BIOLOGICAL MOLECULES
Questions 1–40
1. Which of the following is a monosaccharide?
• A) Sucrose
• B) Glucose
• C) Maltose
• D) Lactose
Answer: B) Glucose
Rationale: Glucose is a monosaccharide (single sugar unit). Sucrose, maltose, and lactose are
disaccharides made of two monosaccharide units.
2. The bond formed between two monosaccharides is a:
• A) Peptide bond
• B) Glycosidic bond
• C) Ester bond
• D) Hydrogen bond
Answer: B) Glycosidic bond
1|Page
,Page 2 of 64
Rationale: A condensation reaction between two monosaccharides forms a glycosidic bond,
releasing a water molecule.
3. Which test is used to detect the presence of starch?
• A) Benedict's test
• B) Iodine test
• C) Biuret test
• D) Emulsion test
Answer: B) Iodine test
Rationale: Iodine solution turns blue-black in the presence of starch.
4. A positive Benedict's test result is indicated by:
• A) Blue colour
• B) Brick-red precipitate
• C) Purple colour
• D) White emulsion
Answer: B) Brick-red precipitate
Rationale: Benedict's test detects reducing sugars; a brick-red precipitate forms on heating.
5. Which of the following is a reducing sugar?
• A) Sucrose
• B) Maltose
• C) Starch
• D) Cellulose
Answer: B) Maltose
Rationale: Maltose is a reducing sugar. Sucrose is a non-reducing sugar. Starch and cellulose are
polysaccharides.
2|Page
,Page 3 of 64
6. Sucrose is a non-reducing sugar. To test for sucrose, the sample must first be:
• A) Heated with Benedict's solution
• B) Boiled with dilute hydrochloric acid, then neutralised
• C) Mixed with iodine
• D) Mixed with ethanol
Answer: B) Boiled with dilute hydrochloric acid, then neutralised
Rationale: Acid hydrolysis breaks sucrose into glucose and fructose, which are reducing sugars.
7. The general formula of a monosaccharide is:
• A) (CH₂O)n
• B) CₙH₂ₙOₙ
• C) CₙH₂ₙ₊₂O
• D) CₙH₂ₙO₂
Answer: A) (CH₂O)n
Rationale: Monosaccharides have the general formula (CH₂O)n, where n is typically 3–7.
8. Which polysaccharide is found in plant cell walls?
• A) Starch
• B) Glycogen
• C) Cellulose
• D) Chitin
Answer: C) Cellulose
Rationale: Cellulose is the main structural polysaccharide in plant cell walls.
9. Which polysaccharide is the main storage carbohydrate in animals?
3|Page
, Page 4 of 64
• A) Starch
• B) Glycogen
• C) Cellulose
• D) Chitin
Answer: B) Glycogen
Rationale: Glycogen is the storage carbohydrate in animals, stored in liver and muscle cells.
10. Starch is a mixture of which two polysaccharides?
• A) Amylose and amylopectin
• B) Cellulose and chitin
• C) Glycogen and cellulose
• D) Amylose and glycogen
Answer: A) Amylose and amylopectin
Rationale: Starch consists of amylose (unbranched) and amylopectin (branched).
11. Which of the following is a function of lipids?
• A) Catalysis of reactions
• B) Energy storage and insulation
• C) Genetic information storage
• D) Oxygen transport
Answer: B) Energy storage and insulation
Rationale: Lipids store energy, provide insulation, and form cell membranes.
12. A triglyceride is formed from:
• A) One glycerol and one fatty acid
• B) One glycerol and three fatty acids
4|Page
