Practice C4.2 Transfer of energy and matter with authentic IB Biology exam questions for both SL and HL students. This question bank mirrors Paper 1A, 1B, 2 structure, covering key topics like cell biology, genetics, and ecology. Get instant solutions, detailed explanations, and build exam confidence with questions in the style of IB examiners.
Paper
Level
Question 1
SLPaper 1A
What is a defining feature of autotrophs?
Question 2
SLPaper 1A
Most ecosystems rely on light as their primary energy source, but deep-sea communities depend on chemoautotrophs that oxidize inorganic compounds to fix carbon. These ecosystems still act as carbon sinks under certain conditions.
What feature allows a chemoautotroph-based ecosystem to function as a carbon sink?
Question 3
SLPaper 1A
Despite high rates of primary production in tropical forests, most food chains remain short, rarely extending beyond four trophic levels.
Which factor best limits the length of food chains in such ecosystems?
Question 4
SLPaper 1A
Which characteristic of water vapour classifies it as a greenhouse gas?
Question 5
SLPaper 1A
In ecosystems, matter cycles through decomposers and consumers, while energy flows in one direction—from external sources through trophic levels and eventually lost as heat.
Which statement best explains why the number of organisms decreases at each successive trophic level?
Question 6
SLPaper 2
The electron micrograph shows palisade mesophyll cells.
1.[1]
State the name of the structures labelled I and III.
2.[2]
Distinguish between autotrophic nutrition and heterotrophic nutrition.
3.[2]
Outline the function of the structure labelled I.
4.[1]
The plant from which this cell was taken is in the group Angiospermophyta. State one characteristic that is unique to this group of plants.
5.[3]
Explain how energy and nutrients are transferred in ecosystems.
Question 7
SLPaper 1A
An energy pyramid shows at the producer level, but only at the tertiary consumer level.
Which best explains this sharp decline?
Question 8
SLPaper 1A
Which activity directly contributes the most to recent increases in atmospheric CO₂ concentrations?
Question 9
SLPaper 1A
In a grassland biome, gross primary production is high, but the net gain in herbivore biomass is low.
Which factor most directly explains low secondary production despite high productivity?
Question 10
SLPaper 1A
The Keeling Curve shows both a seasonal pattern and a long-term increase in atmospheric carbon dioxide. While photosynthesis lowers seasonally, combustion and decomposition increase it year-round.
What explains the seasonal dips observed in the Keeling Curve?