AP Environmental Science : Photosynthesis

Study concepts, example questions & explanations for AP Environmental Science

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Example Questions

Example Question #1 : Energy And Biochemical Cycles

Which of the following most closely approximates the percent of solar energy entering earth available for photosynthetic activity in plants?

Possible Answers:

5%

10%

50%

25%

1%

Correct answer:

1%

Explanation:

Much of the solar energy that enters earth is absorbed by atmospheric molecules or reflected off of surfaces, and a large portion of the energy is unsuitable for photosynthesis. Photosynthesis is powered by light energy that has wavelengths ranging from 400 to 700 nanometers (nm), while sunlight has a wavelength range from 250 to 2500 nm. As a result, only about 1% of available solar energy is used for photosynthetic activity.

Example Question #1 : Energy Dynamics

 

Which of the following aspects of the photosynthetic process accounts for why the leaves on trees are typically green?

Possible Answers:

Along with sugars, photosynthesis produces chlorophyll, which is naturally green.

Chlorophyll absorbs light wavelengths in the purple, blue, and orange spectrums and reflects wavelengths in the green spectrum.

Charged electrons, a vital component of the transport of energy in photosynthesis, emit light in the green spectrum when excited by energy.

Chlorophyll reflects light wavelengths in the purple, blue, and orange spectrums and absorbs wavelengths in the green spectrum.

The oxidation-reduction reactions present in photosynthesis produce a chemical byproduct that is green in color.

Correct answer:

Chlorophyll absorbs light wavelengths in the purple, blue, and orange spectrums and reflects wavelengths in the green spectrum.

Explanation:

Chlorophyll a and b absorb visible light wavelengths in the purple, blue, and red ranges of the visible spectrum of light and reflect visible light in the green range. The green color of leaves is a result of the green visible light being reflected back and isolated from the other visible colors in the spectrum that were absorbed.

Example Question #2 : Energy Dynamics

Photosynthesis involves each of the following as reactants or products except __________.

Possible Answers:

water (H2O)

oxygen (O2)

phosphorus (P)

glucose (C6H12O6)

Photosynthesis involves all of the other answer choices as reactants or products.

Correct answer:

phosphorus (P)

Explanation:

During photosynthesis, plants and algae use solar energy to convert carbon dioxide and water to glucose and oxygen. Phosphorus is not involved in the photosynthesis chemical reaction as a reactant or product.

Example Question #3 : Energy Dynamics

Photosynthesis is the reverse reaction of what cellular process?

Possible Answers:

Neutralization

Chemosynthesis

Respiration

Combustion

Correct answer:

Respiration

Explanation:

Cellular respiration is the opposite reaction of photosynthesis:

Photosynthesis converts carbon dioxide, water, and solar energy to sugar and oxygen. Respiration uses oxygen and sugars to provide a cell with energy. Water and carbon dioxide are produced as byproducts. Note that the form of energy used in photosynthesis is sunlight, while the form of energy produced during respiration is chemical energy.

Example Question #4 : Energy Dynamics

In deep sea vents, certain types of bacteria can produce glucose in a different way than photosynthesis. This process is called __________.

Possible Answers:

chemiosmosis

photosynthesis

chemosynthesis

nucleosynthesis

Correct answer:

chemosynthesis

Explanation:

Using energy from the bonds in, for example, hydrogen sulfide or methane, and carbon dioxide, deep sea bacteria can produce sugars identical to those produced in plants via photosynthesis. This is incredibly important for life in deep water where there is no light.

Example Question #5 : Energy Dynamics

Which of these describes an individual that converts sun energy into food?

Possible Answers:

Producer

Consumer

Decomposer

Herbivore

Detritivore

Correct answer:

Producer

Explanation:

The correct response is producer. A producer converts sunlight into food using photosynthesis. This includes plants, algae, and some fungi. They are sometimes refereed to as primary producers or autotrophs. The big take-home point: producers make their own food. 

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