AP Biology : Understanding Eco-Chemical Cycles

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #41 : Ecology

How does carbon return to the atmospheric biosphere from the terrestrial biosphere?

Possible Answers:

All of these

Animal respiration

Soil respiration

Plant respiration

Correct answer:

All of these

Explanation:

Carbon that is contained in the terrestrial biosphere leaves and returns to the atmospheric biosphere through animal, plant, and soil respiration. These terms refer to the process by which food molecules (ie. glucose) are burned and converted to more usable forms of energy. The byproducts are often carbon dioxide, water, and heat. In animal respiration, carbon dioxide is produced during the transition step between glycolysis and Krebs cycle, and twice in the Krebs cycle.

Example Question #42 : Ecology

How do plants and animals receive carbon, respectively?

Possible Answers:

They don't need to receive carbon

Absorption from the atmosphere

Consumption and photosynthesis

Photosynthesis and consumption

Correct answer:

Photosynthesis and consumption

Explanation:

Plants and animals receive carbon through photosynthesis and consumption, respectively.

Example Question #43 : Ecology

How does carbon from terrestrial organisms enter oceans and bodies of water?

Possible Answers:

Dead tissue only

Respiration and dead tissue

Respiration only

Dead tissue, shells, and dissolution

Shells only

Correct answer:

Dead tissue, shells, and dissolution

Explanation:

Carbon from terrestrial organisms can enter into the oceanic biosphere and bodies of water through dead tissue, dissolution, or in the form of shells as calcium carbonate.

Example Question #44 : Ecology

How does burning fossil fuels impact the carbon cycle?

Possible Answers:

Releases carbon into the geosphere

Removes carbon from the cycle altogether

Releases carbon from the geosphere into the atmospheric biosphere

It doesn't impact the carbon cycle

Correct answer:

Releases carbon from the geosphere into the atmospheric biosphere

Explanation:

Industrialization has increased the burning of fossil fuels, such as coal and oil. This releases carbon from the geosphere into the atmosphere, increasing the carbon in the atmosphere. Carbon dioxide and methane are big contributors to the greenhouse effect and global warming.

Example Question #45 : Ecology

What human activities do not impact the carbon cycle?

Possible Answers:

Pollution

Increase in land use

Deforestation

Clean energy use

Correct answer:

Clean energy use

Explanation:

Modern human activities greatly impact the carbon cycle. Increase in land usage decreases the presence of natural ecosystems and the ability of organisms to remove carbon from the atmosphere. Pollution damages organisms, which reenters the terrestrial biosphere and increases erosion. Deforestation directly removes carbon rom ecosystems and decreases the amount of carbon absorbed from the atmospheric biosphere.

Example Question #46 : Ecology

Which of the following are levels of the carbon cycle?

Possible Answers:

Terrestrial biosphere

Geosphere

All of these

Atmospheric biosphere

Correct answer:

All of these

Explanation:

The carbon cycle includes three levels: the geosphere, the terrestrial biosphere, and the atmospheric biosphere. The geosphere refers to the solid part of the earth, the terrestrial biosphere refers to all the living organisms on the land, and the atmospheric biosphere refers to the living organisms in space between the land and the outer ends of the atmosphere. Carbon is present in all levels and travels throughout the levels through various processes including photosynthesis, dissolution, and decay.

Example Question #47 : Ecology

Which of the following best explains where nitrogen can be found in the terrestrial biosphere?

Possible Answers:

All of these

Decomposing matter

Living organisms

Humus

Correct answer:

All of these

Explanation:

Nitrogen is necessary for all life; therefore, it is present in the territorial biosphere in living organisms, humus, and decomposing matter.

Example Question #48 : Ecology

Which of the following best describes the process of nitrogen fixation?

Possible Answers:

Plants absorb nitrogen from the soil

Organic nitrogen is converted into ammonia by bacteria

Nitrates are converted into nitrogen gas by bacteria

Bacteria fixes atmospheric nitrogen into ammonia

Correct answer:

Bacteria fixes atmospheric nitrogen into ammonia

Explanation:

Nitrogen fixation can be described as the process in the nitrogen cycle in which bacteria “fix” atmospheric nitrogen into ammonia and usable forms of organic nitrogen.

Example Question #49 : Ecology

Which of the following is not true regarding the assimilation stage of the nitrogen cycle?

Possible Answers:

Nitrogen is incorporated into plants through roots as nitrate ions, nitrite ions, and ammonium ions

Symbiotic bacteria may aid with absorption of nitrogen from the soil

Atmospheric nitrogen is converted into organic nitrogen

Plants absorb nitrogen from the soil

Correct answer:

Atmospheric nitrogen is converted into organic nitrogen

Explanation:

In the process of assimilation, organic nitrogen is incorporated into plants through the roots. The type of nitrogen incorporated may be nitrate ions, nitrite ions, or ammonium ions. Symbiotic bacteria may assist this process.

Example Question #41 : Ecology

Bacteria convert dead organic tissue into which of the following forms of nitrogen?

Possible Answers:

Nitrogen gas

Nitrate

Nitrite

Ammonium

Correct answer:

Ammonium

Explanation:

During ammonification, saprobiotic bacteria convert dead organic nitrogen in the soil into ammonium.

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