IB Biology (SL and HL) Examination Exam
Question 1. Which property of water allows it to dissolve many substances important for life?
A) High viscosity
B) Non-polarity
C) Universal solvent ability
D) Low surface tension
Answer: C
Explanation: Water’s polarity allows it to dissolve ionic and polar substances, making it a universal
solvent, essential for biochemical reactions.
Question 2. What type of bond is responsible for the cohesion between water molecules?
A) Ionic bond
B) Hydrogen bond
C) Covalent bond
D) Disulfide bond
Answer: B
Explanation: Hydrogen bonds form between the slightly positive hydrogen atom of one water
molecule and the slightly negative oxygen atom of another, resulting in cohesion.
Question 3. Which property of water is most directly responsible for the regulation of temperature
in living organisms?
A) High density
B) High specific heat capacity
C) Low boiling point
D) Neutral pH
Answer: B
Explanation: Water’s high specific heat capacity allows it to absorb and release large amounts of
heat with little temperature change, stabilizing temperatures in organisms.
Question 4. Which of the following correctly describes a nucleotide found in DNA?
A) Ribose, phosphate, uracil
B) Deoxyribose, phosphate, thymine
C) Ribose, phosphate, thymine
D) Deoxyribose, phosphate, uracil
Answer: B
Explanation: DNA nucleotides contain deoxyribose sugar, a phosphate group, and one of four
nitrogenous bases, including thymine.
Question 5. Which statement best describes the central dogma of molecular biology?
A) RNA → DNA → Protein
B) DNA → RNA → Protein
C) Protein → RNA → DNA
D) RNA → Protein → DNA
Answer: B
Explanation: The central dogma states that genetic information flows from DNA to RNA to protein
via transcription and translation.
Question 6. Which of the following is NOT a universal feature of all cells?
A) Plasma membrane
B) Nucleus
C) Ribosomes
, IB Biology (SL and HL) Examination Exam
D) Cytoplasm
Answer: B
Explanation: All cells have plasma membranes, ribosomes, and cytoplasm, but only eukaryotic cells
contain a nucleus.
Question 7. Prokaryotic cells differ from eukaryotic cells in that prokaryotes lack:
A) Genetic material
B) Ribosomes
C) Membrane-bound organelles
D) Cytosol
Answer: C
Explanation: Prokaryotes lack membrane-bound organelles such as the nucleus, mitochondria, and
endoplasmic reticulum.
Question 8. Which organelle is responsible for the production of ATP in eukaryotic cells?
A) Nucleus
B) Golgi apparatus
C) Mitochondrion
D) Lysosome
Answer: C
Explanation: Mitochondria are the 'powerhouses' of the cell, generating ATP through cellular
respiration.
Question 9. What is the main function of the rough endoplasmic reticulum?
A) Lipid synthesis
B) Protein synthesis and processing
C) DNA replication
D) Detoxification
Answer: B
Explanation: The rough ER is studded with ribosomes and primarily synthesizes and processes
proteins for secretion or use in the membrane.
Question 10. In plant cells, which organelle is responsible for photosynthesis?
A) Mitochondrion
B) Chloroplast
C) Golgi apparatus
D) Nucleus
Answer: B
Explanation: Chloroplasts contain chlorophyll and are the site of photosynthesis in plant cells.
Question 11. Which of the following is a unique feature of viruses compared to living cells?
A) Presence of ribosomes
B) Ability to reproduce independently
C) Lack of metabolic processes
D) Possession of a plasma membrane
Answer: C
Explanation: Viruses lack metabolic processes and must infect host cells to reproduce, distinguishing
them from living cells.
, IB Biology (SL and HL) Examination Exam
Question 12. The lytic cycle of a virus involves:
A) Integration of viral DNA into the host genome
B) Immediate replication and lysis of the host cell
C) Formation of a provirus
D) Dormancy within the host cell
Answer: B
Explanation: In the lytic cycle, viruses replicate rapidly, leading to the destruction (lysis) of the host
cell to release new viral particles.
Question 13. Which kingdom includes organisms that are multicellular, eukaryotic, and autotrophic?
A) Animalia
B) Fungi
C) Plantae
D) Protista
Answer: C
Explanation: Kingdom Plantae consists of multicellular, eukaryotic, autotrophic organisms capable of
photosynthesis.
Question 14. Which domain contains organisms with peptidoglycan in their cell walls?
A) Bacteria
B) Archaea
C) Eukarya
D) Virus
Answer: A
Explanation: Bacteria have peptidoglycan in their cell walls, unlike Archaea and Eukarya.
Question 15. Which phylum is characterized by a notochord present at some stage of development?
A) Arthropoda
B) Chordata
C) Mollusca
D) Annelida
Answer: B
Explanation: Members of the phylum Chordata possess a notochord at some stage, which is a
defining feature.
Question 16. Which of the following is a characteristic of monocotyledonous plants?
A) Net-like leaf veins
B) Two seed leaves
C) Flower parts in multiples of three
D) Taproot system
Answer: C
Explanation: Monocots have floral organs in multiples of three and parallel leaf venation.
Question 17. Which method is primarily used in cladistics to determine evolutionary relationships?
A) Morphological similarities only
B) Shared derived characteristics
C) Geographic distribution
D) Ecological role
Answer: B
, IB Biology (SL and HL) Examination Exam
Explanation: Cladistics uses shared derived characteristics (synapomorphies) to infer evolutionary
relationships.
Question 18. In a cladogram, what does a node represent?
A) A unique species
B) An extinct organism
C) A common ancestor
D) A random mutation
Answer: C
Explanation: Each node on a cladogram represents the most recent common ancestor of the
descendant lineages.
Question 19. Which of the following is direct evidence for common ancestry?
A) Analogous structures
B) Homologous structures
C) Similar behavior patterns
D) Convergent evolution
Answer: B
Explanation: Homologous structures arise from common ancestry and exhibit similar underlying
anatomy.
Question 20. Which process results in populations becoming reproductively isolated, leading to the
formation of new species?
A) Mutation
B) Speciation
C) Genetic drift
D) Natural selection
Answer: B
Explanation: Speciation involves the evolution of reproductive isolation, resulting in the formation of
new species.
Question 21. Which type of selection increases the frequency of traits that enhance survival and
reproduction?
A) Artificial selection
B) Natural selection
C) Directional selection
D) Stabilizing selection
Answer: B
Explanation: Natural selection favors traits that increase fitness in a given environment.
Question 22. Which is an example of allopatric speciation?
A) Polyploidy in plants
B) Behavioral isolation in birds
C) Geographic separation of populations
D) Temporal isolation in frogs
Answer: C
Explanation: Allopatric speciation occurs when populations are physically separated, preventing
gene flow.
Question 1. Which property of water allows it to dissolve many substances important for life?
A) High viscosity
B) Non-polarity
C) Universal solvent ability
D) Low surface tension
Answer: C
Explanation: Water’s polarity allows it to dissolve ionic and polar substances, making it a universal
solvent, essential for biochemical reactions.
Question 2. What type of bond is responsible for the cohesion between water molecules?
A) Ionic bond
B) Hydrogen bond
C) Covalent bond
D) Disulfide bond
Answer: B
Explanation: Hydrogen bonds form between the slightly positive hydrogen atom of one water
molecule and the slightly negative oxygen atom of another, resulting in cohesion.
Question 3. Which property of water is most directly responsible for the regulation of temperature
in living organisms?
A) High density
B) High specific heat capacity
C) Low boiling point
D) Neutral pH
Answer: B
Explanation: Water’s high specific heat capacity allows it to absorb and release large amounts of
heat with little temperature change, stabilizing temperatures in organisms.
Question 4. Which of the following correctly describes a nucleotide found in DNA?
A) Ribose, phosphate, uracil
B) Deoxyribose, phosphate, thymine
C) Ribose, phosphate, thymine
D) Deoxyribose, phosphate, uracil
Answer: B
Explanation: DNA nucleotides contain deoxyribose sugar, a phosphate group, and one of four
nitrogenous bases, including thymine.
Question 5. Which statement best describes the central dogma of molecular biology?
A) RNA → DNA → Protein
B) DNA → RNA → Protein
C) Protein → RNA → DNA
D) RNA → Protein → DNA
Answer: B
Explanation: The central dogma states that genetic information flows from DNA to RNA to protein
via transcription and translation.
Question 6. Which of the following is NOT a universal feature of all cells?
A) Plasma membrane
B) Nucleus
C) Ribosomes
, IB Biology (SL and HL) Examination Exam
D) Cytoplasm
Answer: B
Explanation: All cells have plasma membranes, ribosomes, and cytoplasm, but only eukaryotic cells
contain a nucleus.
Question 7. Prokaryotic cells differ from eukaryotic cells in that prokaryotes lack:
A) Genetic material
B) Ribosomes
C) Membrane-bound organelles
D) Cytosol
Answer: C
Explanation: Prokaryotes lack membrane-bound organelles such as the nucleus, mitochondria, and
endoplasmic reticulum.
Question 8. Which organelle is responsible for the production of ATP in eukaryotic cells?
A) Nucleus
B) Golgi apparatus
C) Mitochondrion
D) Lysosome
Answer: C
Explanation: Mitochondria are the 'powerhouses' of the cell, generating ATP through cellular
respiration.
Question 9. What is the main function of the rough endoplasmic reticulum?
A) Lipid synthesis
B) Protein synthesis and processing
C) DNA replication
D) Detoxification
Answer: B
Explanation: The rough ER is studded with ribosomes and primarily synthesizes and processes
proteins for secretion or use in the membrane.
Question 10. In plant cells, which organelle is responsible for photosynthesis?
A) Mitochondrion
B) Chloroplast
C) Golgi apparatus
D) Nucleus
Answer: B
Explanation: Chloroplasts contain chlorophyll and are the site of photosynthesis in plant cells.
Question 11. Which of the following is a unique feature of viruses compared to living cells?
A) Presence of ribosomes
B) Ability to reproduce independently
C) Lack of metabolic processes
D) Possession of a plasma membrane
Answer: C
Explanation: Viruses lack metabolic processes and must infect host cells to reproduce, distinguishing
them from living cells.
, IB Biology (SL and HL) Examination Exam
Question 12. The lytic cycle of a virus involves:
A) Integration of viral DNA into the host genome
B) Immediate replication and lysis of the host cell
C) Formation of a provirus
D) Dormancy within the host cell
Answer: B
Explanation: In the lytic cycle, viruses replicate rapidly, leading to the destruction (lysis) of the host
cell to release new viral particles.
Question 13. Which kingdom includes organisms that are multicellular, eukaryotic, and autotrophic?
A) Animalia
B) Fungi
C) Plantae
D) Protista
Answer: C
Explanation: Kingdom Plantae consists of multicellular, eukaryotic, autotrophic organisms capable of
photosynthesis.
Question 14. Which domain contains organisms with peptidoglycan in their cell walls?
A) Bacteria
B) Archaea
C) Eukarya
D) Virus
Answer: A
Explanation: Bacteria have peptidoglycan in their cell walls, unlike Archaea and Eukarya.
Question 15. Which phylum is characterized by a notochord present at some stage of development?
A) Arthropoda
B) Chordata
C) Mollusca
D) Annelida
Answer: B
Explanation: Members of the phylum Chordata possess a notochord at some stage, which is a
defining feature.
Question 16. Which of the following is a characteristic of monocotyledonous plants?
A) Net-like leaf veins
B) Two seed leaves
C) Flower parts in multiples of three
D) Taproot system
Answer: C
Explanation: Monocots have floral organs in multiples of three and parallel leaf venation.
Question 17. Which method is primarily used in cladistics to determine evolutionary relationships?
A) Morphological similarities only
B) Shared derived characteristics
C) Geographic distribution
D) Ecological role
Answer: B
, IB Biology (SL and HL) Examination Exam
Explanation: Cladistics uses shared derived characteristics (synapomorphies) to infer evolutionary
relationships.
Question 18. In a cladogram, what does a node represent?
A) A unique species
B) An extinct organism
C) A common ancestor
D) A random mutation
Answer: C
Explanation: Each node on a cladogram represents the most recent common ancestor of the
descendant lineages.
Question 19. Which of the following is direct evidence for common ancestry?
A) Analogous structures
B) Homologous structures
C) Similar behavior patterns
D) Convergent evolution
Answer: B
Explanation: Homologous structures arise from common ancestry and exhibit similar underlying
anatomy.
Question 20. Which process results in populations becoming reproductively isolated, leading to the
formation of new species?
A) Mutation
B) Speciation
C) Genetic drift
D) Natural selection
Answer: B
Explanation: Speciation involves the evolution of reproductive isolation, resulting in the formation of
new species.
Question 21. Which type of selection increases the frequency of traits that enhance survival and
reproduction?
A) Artificial selection
B) Natural selection
C) Directional selection
D) Stabilizing selection
Answer: B
Explanation: Natural selection favors traits that increase fitness in a given environment.
Question 22. Which is an example of allopatric speciation?
A) Polyploidy in plants
B) Behavioral isolation in birds
C) Geographic separation of populations
D) Temporal isolation in frogs
Answer: C
Explanation: Allopatric speciation occurs when populations are physically separated, preventing
gene flow.
