All High School Biology Resources
Example Questions
Example Question #3 : Understanding The Carbon Cycle
Attempt to draw out the Carbon cycle to the best of your abilities without looking up a photo before answering this problem.
Which of the following is not one of the major carbon stores on Earth?
The ocean
The lithosphere
The biosphere
The atmosphere
The ocean floor
The ocean floor
All of the other choices asides from the ocean floor are major carbon stores. The atmosphere contains large amounts of carbon dioxide despite composing just a fraction of a percent of the Earth's atmosphere. The lithosphere contains large amounts of coal, oil and natural gas all of which are various mixtures of carbon containing compounds. The ocean dissolves and stores large amount of the atmosphere's carbon dioxide and the biosphere is all inclusive of living organism which are carbon based and contain a wide variety of carbon compounds.
Example Question #4 : Understanding The Carbon Cycle
By what method is the majority of carbon moved from the lithosphere to the atmosphere?
The burning of fossil fuels
Erosion
Respiration
Weathering
Deposition
The burning of fossil fuels
Only three of the five answers listed move carbon from the lithosphere to the atmosphere and of these the burning of fossil fuels moves the majority of the carbon that is moved from the lithosphere to the atmosphere.
Example Question #5 : Understanding The Carbon Cycle
What kind of organism sequesters the most carbon from the atmosphere?
Bacteria
Plants
Archaea
Insects
Animals
Plants
Due to cell structure containing cell walls composed of cellulose made of the densely interwoven sheets of the six-carbon sugar glucose plants sequester large amounts of carbon in their cell walls.
Example Question #1 : Understanding The Nitrogen Cycle
Why can plants not utilize naturally occurring nitrogen gas?
Most of the nitrogen is stored as nitrate (NO3-)
Lack of nitrogen-fixing bacteria
Plants cannot break the triple bond between the two nitrogen atoms
There are insufficient amounts available in the atmosphere
Plants cannot break the triple bond between the two nitrogen atoms
Like carbon, nitrogen is one the most abundant elements in biotic factors. Nitrogen gas is highly abundant in our atmosphere, however it cannot be utilized by humans and plants while in its gaseous state because of the very strong triple bond between the two nitrogen atoms. For plants to use nitrogen, they must have it converted to ammonium or nitrate by bacteria found in the soil and roots. The process of converting nitrogen gas to ammonium is called nitrogen fixation. Decomposition of plants and animals also releases ammonium into the ground. This ammonium can be further converted to nitrate with the help of nitrifying bacteria. Returning nitrogen back to the atmosphere is called denitrification. This process is carried out by some bacteria found in lakes and swamps. These bacteria are anaerobic, so they use the nitrate and release nitrogen gas into the air.
Example Question #1 : Understanding The Nitrogen Cycle
Which of the following is most directly responsible for nitrogen fixation?
Sunlight
Bacteria
Animals
Humans
Plant roots
Bacteria
Nitrogen fixation is mostly done by bacteria living in the soil. Plants need nitrogen to grow, but they cannot use it straight from the atmosphere or as ammonia from the soil.
Humans and animals largely obtain their necessary nitrogen by consuming plants, and do not fix nitrogen or rely directly on bacteria for the process.
Example Question #1 : Understanding The Nitrogen Cycle
Which of the following biological processes is not linked to the nitrogen cycle?
Ammonification
Denitrification
Nitrogen fixation
Assimilation by plants
Condensation
Condensation
Condensation is not part of the nitrogen cycle. It is part of the water cycle, during which water molecules condense together in the atmosphere to form clouds.
Example Question #1 : Understanding The Nitrogen Cycle
Nitrification is the process of turning __________ into __________.
N2 . . . NH3
NO3- . . . plants
NO3- . . . N2
animal waste . . . NH3
NO2- . . . NO3-
NO2- . . . NO3-
Nitrification is the process by which nitrite (NO2-) is converted to nitrate (NO3-). This is the final step required in the processes used to oxidize nitrogen wastes (ammonia) to usable nitrate ions.
The conversion of gaseous nitrogen to ammonia (N2 to NH3) describes nitrogen fixation, and is usually done by nitrogen-fixing bacteria.
The conversion of nitrate to plant matter (NO3- to plants) describes the process of assimilation.
The conversion of nitrate to gaseous nitrogen (NO3- to N2) describes denitrification, and is performed by denitrification bacteria.
The conversion of animal waste to NH3 describes ammonification, and is accomplished by saprobiotic (decomposing) bacteria.
Example Question #1 : Understanding The Nitrogen Cycle
How do plants obtain nitrogen?
From water
From the soil using their roots
Plants do not use nitrogen
From the atmosphere
From the soil using their roots
The nitrogen in plants comes from the soil. Bacteria in the soil take nitrogenous wastes and convert it into forms of nitrogen that plants can use. Plants then take up nitrogen through their roots.
Example Question #1 : Understanding The Nitrogen Cycle
What is the largest natural reservoir nitrogen on earth?
The geosphere
The sun
The biosphere
The hydrosphere
The Earth's atomosphere
The Earth's atomosphere
The atmosphere is composed of 78% nitrogen gas and while by mass the atmosphere is less massive than the all the other choices the other choices are not primarily composed of nitrogen and contain relatively little compared to the nitrogen in the atmosphere.
Example Question #2 : Understanding The Nitrogen Cycle
Is the majority of the Earth's nitrogen immediately available for use by plants and other living organisms? Why?
Yes, because the majority of the world's nitrogen is present in ammonium
No, most of it exists as inorganic nitrogen gas and is not immediately usable to most organisms.
No, because the majority of the world's nitrogen is locked in geological reservoirs
No, because nitrogen gas is not able to be converted to other forms.
Yes, because the nitrogen gas that composes the atmosphere is usable to most organisms.
No, most of it exists as inorganic nitrogen gas and is not immediately usable to most organisms.
Since the nitrogen gas that composes 78% of the atmosphere is not immediately usable to all organisms except for nitrogen-fixing organisms the nitrogen that composes the Earth's major nitrogen reserve is not immediately usable to most organisms.
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