Practice 2.9 Photosynthesis 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
Which carbon compound produced by living organisms is inorganic?
Question 2
SLPaper 1A
Which of the following processes occurs during the light-dependent reactions of photosynthesis?
Question 3
HLPaper 1A
How is oxygen produced during photosynthesis?
Question 4
SLPaper 2
1.[6]
Draw and label a diagram of the carbon cycle.
2.[4]
Outline the effect of carbon dioxide concentration on the rate of photosynthesis and how this can be measured by carbon dioxide uptake.
3.[5]
Explain how carbon dioxide is produced in anaerobic and in aerobic respiration.
Question 5
SLPaper 2
1.
[2]
Compare and contrast the mode of nutrition of detritivores and saprotrophs.
| Detritivores | Saprotrophs | |
|---|---|---|
| Similarity | ||
| Difference |
2.[1]
Draw a food chain from this food web, showing at least three organisms.
3.[2]
Explain the reasons for food chains rarely containing more than four or five trophic levels.
4.[2]
The amount of food passing into food chains can be affected by the rate of photosynthesis. Explain the effect of one limiting factor on photosynthesis.
5.[1]
All of the leaves in the image are from Solanum, a wild genus of tomato.
State one cause of variation in a plant such as the tomato.
Question 6
SLPaper 1A
What is the source of carbon for the following organisms?
| Autotrophs | Heterotrophs | Saprotrophs | |
|---|---|---|---|
| A. | Organic | Inorganic | Organic |
| B. | Inorganic | Organic | Organic |
| C. | Organic | Organic | Organic |
| D. | Inorganic | Inorganic | Inorganic |
Question 7
SLPaper 1A
What benefit is derived from the use of Bt crops?
Question 8
SLPaper 2
Phenologists are biologists who study the timing of seasonal activities in animals and plants, such as the opening of tree leaves and the laying of eggs by birds. Data such as these can provide evidence of climate changes, including global warming. The date in the spring when new leaves open on horse chestnut trees (Aesculus hippocastaneum) has been recorded in Germany every year since 1951. The graph below shows the difference between each year's date of leaf opening and the mean date of leaf opening between 1970 and 2000. Negative values indicate that the date of leaf opening was earlier than the mean. The graph also shows the difference between each year's mean temperature during March and April and the overall mean temperature for these two months. The data for temperature was obtained from the records of thirty-five German climate stations. 
[Source: Walther et al., Nature (2002), 416, pages 389-395] From 1973 onwards phenologists in the Netherlands have been studying a population of great tits (Parus major) in a forest on the Hoge Veluwe. Nest boxes are checked every week to find out when the great tits lay their eggs and how many eggs they lay. Young birds are ringed when they are seven days old, to allow the reproductive success of their parents to be monitored. Great tits feed on arthropods, especially caterpillars. The phenologists found that the date of maximum caterpillar biomass each year in the forest could be estimated accurately using temperature records. The graphs below show the mean date of egg laying and the estimated date of maximum caterpillar biomass for each year from 1973 to 1995. 
[Source: Visser, Noordwijk, Tinbergen and Lessells, Proceedings of the Royal Society of London, (1998), 265, pages 1867-1870] There was no statistically significant change in the date of egg laying between 1973 and 1995, but the phenologists found evidence that natural selection will eventually cause a change in the date of egg laying.
1.[1]
Identify the year in which there was the earliest opening of horse chestnut leaves.
2.[1]
Identify the year in which there was the lowest mean temperature in March and April.
3.[1]
Use the data in the graph to deduce the relationship between temperatures in March and April and the date of opening of leaves on horse chestnut trees.
4.[2]
Use the data in the graph to deduce whether there is evidence of global warming towards the end of the twentieth century.
5.[1]
Compare the date of egg laying with the date of maximum caterpillar biomass.
6.[1]
Suggest an advantage to great tits of the difference in dates.
7.[1]
State the trend, shown in the graph, for the date of maximum caterpillar biomass.
8.[2]
Explain how natural selection could cause a change in the date of egg laying in the population of great tits in the forest on the Hoge Veluwe.
Question 9
HLPaper 1A
In the diagram of a chloroplast below where will the Calvin cycle take place?
Question 10
SLPaper 1A
Which process produces the most ATP per molecule of glucose?