Lesson Worksheet: The Nitrogen Cycle Biology
In this worksheet, we will practice describing the nitrogen cycle, and explaining the importance of nitrates for plants.
Q1:
In what form do plants absorb the majority of nitrogen from the soil?
- AGaseous nitrogen
- BNitrous oxide
- CNitrogen dioxide
- DNitrites
- ENitrates
Q2:
Which of the following best explains why plants need to absorb nitrogen from the soil?
- APlants require nitrogen to aid the movement of sucrose through the plant.
- BPlants require nitrogen to synthesize important nitrogen-containing compounds, like proteins.
- CPlants require nitrogen to be broken down during cellular respiration to release energy.
- DPlants require nitrogen as it is a reactant in the process of photosynthesis.
Q3:
The picture shows root nodules on a pea plant. Those root nodules are colonized by nitrogen-fixing bacteria.
The relationship between the bacteria and the pea plant is described as mutualistic; what does this mean?
- AThe pea plant benefits from the relationship, but the bacteria do not.
- BThe bacteria benefit from the relationship, but the pea plant does not.
- CBoth the bacteria and the pea plant benefit from this relationship.
- DNeither the bacteria nor the pea plant benefits from this relationship.
Q4:
Legumes (e.g., pea plants) are able to increase the level of soil nitrogen where they are planted. Which of the following is a benefit this provides?
- AAn increase in soil nitrogen means less nitrogen-fixing bacteria will be present in the soil.
- BThere is more nitrogen available in the soil for other crops that are planted there.
- CThere is less nitrogen in the soil after they are removed, so there is less to be converted into nitrogen gas.
- DAn increase in soil nitrogen means this soil can be used as fertilizer elsewhere.
Q5:
Which organisms convert nitrates in the soil back into atmospheric nitrogen?
- ADecomposers
- BNitrifying bacteria
- CDenitrifying bacteria
- DNitrogen-fixing bacteria
Q6:
Which organisms in the nitrogen cycle convert ammonium ions into nitrites and then into nitrates?
- ADenitrifying bacteria
- BDecomposers
- CNitrogen-fixing bacteria
- DNitrifying bacteria
Q7:
Which organisms in the nitrogen cycle convert proteins, contained in urea and the bodies of dead organisms, into ammonia?
- ANitrogen-fixing bacteria
- BDecomposers
- CNitrifying bacteria
- DDenitrifying bacteria
Q8:
Why can plants not absorb nitrogen directly from the atmosphere?
- AGaseous nitrogen is too unreactive to be absorbed and used by plants.
- BGaseous nitrogen is too reactive to be taken in directly by plants and must go through the roots.
- CNitrogen only makes up less than of the gases in the atmosphere, so there is not enough to be absorbed.
- DNitrogen in the atmosphere evaporates before it can be absorbed.
Q9:
Which organisms involved in the nitrogen cycle convert nitrogen gas into nitrogen compounds in the soil?
- ANitrifying bacteria
- BNitrogen-fixing bacteria
- CDecomposers
- DDenitrifying bacteria
Q10:
Farmers can use a technique where each year they plant a different crop in different fields in a fixed order. This helps maintain good levels of soil nitrogen. What is this technique called?
- ACrop swap
- BCrop alternating
- CCrop migration
- DCrop rotation
Practice Means Progress
Boost your grades with free daily practice questions. Download Nagwa Practice today!
