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Pre AP Biology -ECO 1.2 Carbon and Nutrient Cycles- FRQ Exam Style Questions -New Syllabus

Pre AP Biology -ECO 1.2 Carbon and Nutrient Cycles- FRQ Exam Style Questions – New Syllabus 2025-2026

Pre AP Biology -ECO 1.2 Carbon and Nutrient Cycles- FRQ Exam Style Questions – Pre AP Biology – per latest Pre AP Biology Syllabus.

Pre AP Biology – FRQ Exam Style Questions- All Topics

Question

Carbon and Nitrogen move through the environment via ecological cycles.
a. Identify and explain two carbon cycle processes that add carbon dioxide to the atmosphere.
b. Identify and explain one carbon cycle process that removes carbon dioxide from the atmosphere.
c. Describe one action that humans could take to reduce levels of carbon dioxide, and explain how the action would reduce carbon dioxide levels.
d. How is nitrogen removed from the atmosphere and converted into a usable form for plants?

Most-appropriate topic codes:

• TOPIC: ECO 1.2 — Carbon and Nutrient Cycles: Explaining the importance and molecular transformations of the carbon and nitrogen cycles — parts (a), (b), (d)
• TOPIC: CELLS 7.1 — Cellular Respiration: Understanding how $CO_2$ is produced as a byproduct during energy transfer — part (a)
• TOPIC: CELLS 6.1 — Photosynthesis: Explaining the conversion of solar energy and $CO_2$ into chemical energy (sugars) — part (b)
• TOPIC: ECO 5.2 — Human-Induced Changes in Biodiversity: Designing solutions to mitigate adverse human-induced environmental changes — part (c)
▶️ Answer/Explanation
Detailed solution

(a)
Two processes that add carbon dioxide ($CO_2$) to the atmosphere are:

  • Cellular Respiration: A series of enzymatic reactions where organisms use carbon compounds to synthesize ATP, releasing $CO_2$ as a waste product .
  • Combustion (Human Activity): Human activities such as the use of fossil fuels for energy release carbon dioxide into the atmosphere.

(b)
Photosynthesis is the process that removes carbon dioxide from the atmosphere. Photosynthetic organisms use $CO_2$, ATP, and NADPH to produce sugars, effectively “fixing” the carbon into biological systems.

(c)
Humans can transition to renewable energy sources to reduce fossil fuel combustion.
Explanation: Reducing the burning of fossil fuels mitigates the release of $CO_2$ into the atmosphere. Additionally, protecting diverse ecosystems like forests ensures they continue to serve as reservoirs for carbon.

(d)
Nitrogen is removed from the atmosphere and converted into a usable form through Nitrogen Fixation. In this process, nitrogen gas from the atmosphere (the largest reservoir of nitrogen) is converted into biologically available nitrogen-containing molecules, such as nitrates. This is often facilitated by bacteria in the guts of certain organisms or specialized soil bacteria.

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