IB Biology SL/HL
Practice Exam
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Rationales 2025/2026
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1. What is the primary function of the cell membrane?
A. Protein synthesis
B. Selective permeability
C. Energy production
D. DNA storage
,Rationale: The cell membrane controls what enters and
leaves the cell, maintaining homeostasis.
2. Which organelle is responsible for ATP production?
A. Ribosome
B. Golgi apparatus
C. Mitochondrion
D. Nucleus
Rationale: Mitochondria carry out cellular respiration to
produce ATP.
3. What type of bond holds water molecules together?
A. Ionic bond
B. Hydrogen bond
C. Covalent bond
D. Peptide bond
Rationale: Hydrogen bonds form between partially charged
regions of water molecules.
4. Which molecule stores genetic information?
A. RNA
B. Protein
C. DNA
D. Lipid
Rationale: DNA contains hereditary genetic instructions.
, 5. What is the basic unit of life?
A. Tissue
B. Organ
C. Cell
D. Organ system
Rationale: The cell is the smallest unit capable of life.
6. Which process produces genetically identical cells?
A. Meiosis
B. Mitosis
C. Fertilization
D. Mutation
Rationale: Mitosis produces identical daughter cells.
7. Enzymes are best described as:
A. Lipids
B. Carbohydrates
C. Proteins that catalyze reactions
D. Nucleic acids
Rationale: Enzymes speed up biochemical reactions.
8. What is the function of ribosomes?
A. Lipid synthesis
B. ATP production
C. Protein synthesis
Practice Exam
Questions And Correct
Answers (Verified
Answers) Plus
Rationales 2025/2026
Q&A | Instant
Download Pdf
1. What is the primary function of the cell membrane?
A. Protein synthesis
B. Selective permeability
C. Energy production
D. DNA storage
,Rationale: The cell membrane controls what enters and
leaves the cell, maintaining homeostasis.
2. Which organelle is responsible for ATP production?
A. Ribosome
B. Golgi apparatus
C. Mitochondrion
D. Nucleus
Rationale: Mitochondria carry out cellular respiration to
produce ATP.
3. What type of bond holds water molecules together?
A. Ionic bond
B. Hydrogen bond
C. Covalent bond
D. Peptide bond
Rationale: Hydrogen bonds form between partially charged
regions of water molecules.
4. Which molecule stores genetic information?
A. RNA
B. Protein
C. DNA
D. Lipid
Rationale: DNA contains hereditary genetic instructions.
, 5. What is the basic unit of life?
A. Tissue
B. Organ
C. Cell
D. Organ system
Rationale: The cell is the smallest unit capable of life.
6. Which process produces genetically identical cells?
A. Meiosis
B. Mitosis
C. Fertilization
D. Mutation
Rationale: Mitosis produces identical daughter cells.
7. Enzymes are best described as:
A. Lipids
B. Carbohydrates
C. Proteins that catalyze reactions
D. Nucleic acids
Rationale: Enzymes speed up biochemical reactions.
8. What is the function of ribosomes?
A. Lipid synthesis
B. ATP production
C. Protein synthesis
