Question

nitrogen cycle article questions
multiple choice

1. why is nitrogen essential for living organisms?

a. it is a building block of proteins and nucleic acids.
b. it is a building block of carbohydrates and lipids.
c. it is a building block of vitamins and minerals.

1. how do nitrifying bacteria contribute to the nitrogen cycle?

a. they convert atmospheric nitrogen into organic nitrogen compounds.
b. they convert organic nitrogen compounds into ammonium.
c. they convert ammonium into nitrite and nitrate.

1. what is nitrogen fixation?

a. the conversion of ammonium into nitrate and nitrate
b. the conversion of atmospheric nitrogen into ammonium and other organic nitrogen molecules
c. the conversion of atmospheric nitrogen into organic nitric acid

1. how does lightning fixation occur?

a. lightning causes nitrogen gas molecules to break apart and react with oxygen.
b. lightning causes nitrogen gas molecules to break apart and react with carbon dioxide.
c. lightning causes nitrogen gas molecules to break apart and react with water.

1. what is denitrification?

a. the conversion of nitrite into atmospheric nitrogen
b. the conversion of nitrate into atmospheric nitrogen
c. the conversion of nitrite into nitrate

1. what human activities disrupt the natural nitrogen cycle?

a. overfishing and overharvesting crops
b. combustion of fossil fuels and excessive fertilizer use
c. driving electric cares and excessive overharvesting of crops

1. true or false: decomposers break down the organic matter and convert it into nitrate.

a. true
b. false

1. what process occurs when plants take in these nitrogen compounds from the soil through their roots?

a. assimilation
b. denitrification
c. nitrogen fixation

1. what type of bacteria converts nitrate into atmospheric nitrogen gas?

a. nitrifying bacteria
b. nitrogen - fixing bacteria
c. denitrifying bacteria

1. which of the following is the correct sequence of events in the nitrogen cycle?

a. ammonium → nitrate → nitrite
b. nitrate → nitrite → ammonium
c. ammonium → nitrite → nitrate

1. what type of bacteria live in the soil or root nodules of legumes and convert nitrogen gas into ammonium or other organic nitrogen compounds?

a. nitrifying bacteria
b. nitrogen - fixing bacteria
c. denitrifying bacteria

1. in what type of environment does denitrification typically take place?

a. oxygen - depleted environments like wetlands and soil with poor drainage
b. oxygen - rich environments like mountain tops and rainforest canopies
c. carbon - dioxide rich environments like wetlands and deserts.
short answer

1. describe the sequence of events that occurs when a nitrogen gas atom in an animals dna cycles through in the nitrogen cycle to eventually become an atom of atmospheric nitrogen.

Explanation:

1. Nitrogen is a building - block of proteins and nucleic acids.
2. Nitrifying bacteria convert ammonium into nitrite and nitrate.
3. Nitrogen fixation is the conversion of atmospheric nitrogen into ammonium and other organic nitrogen molecules.
4. Lightning causes nitrogen gas molecules to break apart and react with oxygen.
5. Denitrification is the conversion of nitrate into atmospheric nitrogen.
6. Combustion of fossil fuels and excessive fertilizer use disrupt the natural nitrogen cycle.
7. Decomposers break down organic matter and convert it into ammonium first, then other bacteria convert it to nitrate, so false.
8. Assimilation is when plants take in nitrogen compounds from the soil through their roots.
9. Denitrifying bacteria convert nitrate into atmospheric nitrogen gas.
10. The correct sequence is ammonium → nitrite → nitrate.
11. Nitrogen - fixing bacteria live in the soil or root nodules of legumes and convert nitrogen gas into ammonium or other organic nitrogen compounds.
12. Denitrification typically takes place in oxygen - depleted environments like wetlands and soil with poor drainage.
13. The nitrogen in animal DNA is first released as ammonium when the animal dies and decomposes. Then nitrifying bacteria convert ammonium to nitrite and then to nitrate. Plants can take up nitrate through assimilation. Other bacteria can perform denitrification to convert nitrate back to atmospheric nitrogen.

Answer:

1. a. It is a building block of proteins and nucleic acids.
2. c. They convert ammonium into nitrite and nitrate.
3. b. the conversion of atmospheric nitrogen into ammonium and other organic nitrogen molecules
4. a. Lightning causes nitrogen gas molecules to break apart and react with oxygen.
5. b. the conversion of nitrate into atmospheric nitrogen
6. b. combustion of fossil fuels and excessive fertilizer use
7. b. false
8. a. assimilation
9. c. denitrifying bacteria
10. c. ammonium → nitrite → nitrate
11. b. nitrogen - fixing bacteria
12. a. oxygen - depleted environments like wetlands and soil with poor drainage
13. The nitrogen in animal DNA is released as ammonium upon decomposition. It is then converted to nitrite and nitrate by nitrifying bacteria. Plants may take up nitrate. Finally, denitrifying bacteria convert nitrate back to atmospheric nitrogen.