AP Biology 3.3.A Energy in Living Organisms
Practise AP Biology 3.3.A questions by explaining energy input, metabolic coupling, ATP efficiency and the maintenance of ordered living systems.
- Syllabus
- Effective Fall 2025
- Course
- AP Biology
Exam points
- explain why living systems require energy input to maintain order and power processes
- connect energy-releasing and energy-requiring reactions through metabolic coupling
- calculate energy transfer efficiency and describe excess energy as heat
3.3.A—Describe the role of energy in living organisms question 1
Questions 34-38 A student is investigating photosynthesis in plants. The student planted grass seeds in a tray with three sections and grew the grass under artificial lights for 14 days (Figure 1). After 14 days, the student collected all of the grass from section I and recorded its mass (Table 1). The student then placed a clear cover over section II and placed an aluminum foil cover over section III (Figure 2). The student then placed the tray back under the artificial lights for seven additional days. On day 21, the student collected and measured the mass of the grass from sections II and III (Table 1).
Figure 1. A tray of grass seed, grown under light for 14 days
Figure 2. Modifications made to sections II and III on day 14
TABLE 1. MASS OF GRASS GROWN IN EACH SECTION
Which of the following best explains the connection between energy, growth, and the maintenance of an ordered system in the experiment?
A
Energy input from light is required for the grass to grow and maintain an ordered structure.
B
The grass obtains the energy for growth and maintenance of order from nutrients from the soil.
C
The grass couples the release of energy from the light reactions with the production of oxygen used to produce sugars for growth.
D
Energy is required for the growth of the grass but not the maintenance of order.
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