AP Biology : Understand inputs and outputs, purpose

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #1 : Understand Inputs And Outputs, Purpose

Which of the following is not a reactant used in the process of photosynthesis?

Possible Answers:

Light energy

O2

CO2

H2O

Correct answer:

O2

Explanation:

The process of photosynthesis can be summarized by the following equation.

H2O, CO2, and light energy are thus reactants of photosynthesis, while O2 is only a product.

Example Question #1 : Understand Inputs And Outputs, Purpose

What are the products of photosynthesis?

Possible Answers:

Water and carbon dioxide

Glucose and oxygen

Light and glucose

Carbon dioxide and light

Oxygen and carbon dioxide

Correct answer:

Glucose and oxygen

Explanation:

The photosynthesis equation can be written as:

From this equation, we can see that plants take in carbon dioxide, water, and light energy as reactants and produce glucose and oxygen as products.

Example Question #2 : Understand Inputs And Outputs, Purpose

Some organisms, such as green plants, are capable of obtaining energy directly from photosynthesis. These organisms are termed __________.

Possible Answers:

primary consumers

homotrophs

autotrophs

heterotrophs

herbivores

Correct answer:

autotrophs

Explanation:

Autotrophs are organisms that produce complex organic compounds from substances present in the surroundings. These organisms may do this through the use of energy from light or from inorganic chemical reactions.

In contrast, heterotrophs require organic input in order to generate biological compounds and are unable to use light or inorganic materials for energy.

Example Question #3 : Understand Inputs And Outputs, Purpose

Which of the following is true of photosynthesis? 

Possible Answers:

Electrons decrease in potential energy as they move from water to sugar

Water is reduced

Carbon dioxide is reduced

The process requires no energy

Carbon dioxide is oxidized

Correct answer:

Carbon dioxide is reduced

Explanation:

Photosynthesis occurs in the chloroplasts of plant cells, where carbon dioxide is reduced and water is oxidized to create sugar. During this process electrons demonstrate increased potential energy as they move from water to sugar. The process requires an initial energy input, derived from photons.

Example Question #1 : Understand Inputs And Outputs, Purpose

Organisms that make their organic molecules from inorganic raw materials obtained from the surrounding environment are called __________.

Possible Answers:

plants

heterotrophs

auxotrophs

autotrophs

Correct answer:

autotrophs

Explanation:

Autotrophs create organic material from inorganic materials. Autotrophs are self-feeders in that they do not consume other organic materials but rather create their own organic materials. Plants and other photosynthetic organisms are examples of autotrophs.   

Example Question #1 : Understand Inputs And Outputs, Purpose

Plants are an example of which of the following categories of organisms?

Possible Answers:

Autotrophs

Biosphere consumers

Chemoautotrophs

Heterotrophs

Correct answer:

Autotrophs

Explanation:

Plants are an example of autotrophs. Autotrophs sustain themselves without consuming other organic material. Instead they create organic material from inorganic materials.

Example Question #2 : Understand Inputs And Outputs, Purpose

Which of the following are referred to as the major sites of photosynthesis in most plants?

Possible Answers:

Flowers

Leaves

Stems

Roots

Correct answer:

Leaves

Explanation:

The leaves are the major sites of photosynthesis in most plants. The chloroplasts are located in the mesophyll—interior tissues of the leaves—and are the primary sites of photosynthesis.

Example Question #3 : Understand Inputs And Outputs, Purpose

Photosynthesis is commonly divided into how many primary stages?

Possible Answers:

Four stages

Two stages

One stage

Three stages

Correct answer:

Two stages

Explanation:

The correct answer is two major stages. The first stage is known as the light reactions where solar energy is converted to chemical energy. The second stage is the Calvin cycle that synthesizes sugar.

Example Question #4 : Understand Inputs And Outputs, Purpose

Which of the following is one of the end products of photosynthesis?

Possible Answers:

Lipids

Water

Carbon dioxide

Glucose

Correct answer:

Glucose

Explanation:

Glucose is the six carbon sugar that is the main product of photosynthesis. Water and carbon dioxide are the reactants in photosynthesis. Lipids are fat molecules that store energy in cells.

Example Question #5 : Understand Inputs And Outputs, Purpose

Which of the following is not true regarding photosynthesis?

Possible Answers:

Water is a product

It is a nonspontaneous reaction

Carbon dioxide is a reactant

Glucose is a product

Correct answer:

Water is a product

Explanation:

In photosynthesis, water, carbon dioxide, and energy in the form of sunlight are inputs, and the outputs are glucose and oxygen. A nonspontaneous reaction is one that will not proceed without the net input of energy (in this case, sunlight).

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