Biol 221 Lec 37 MCQ

Front

What is dissimilative nitrogen fixation?

Back

A process where certain bacteria convert nitrogen gas (N2) into ammonia (NH3) without incorporating it into organic molecules, primarily for energy production.

Front

What is biofilm formation in bacteria?

Back

A process where bacteria adhere to surfaces and each other, creating a protective layer that enhances their survival and growth in various environments.

Front

What role do heterotrophs play in an ecosystem?

Back

Heterotrophs consume organic matter, decompose complex organic materials, and produce CO2, but they do not reduce CO2 using energy from other chemical reactions.

Front

Where is leghemoglobin produced in a Rhizobium root nodule?

Back

Leghemoglobin is produced in area B of the nodule, which is involved in assimilatory nitrogen fixation.

Front

What is the lifestyle and production characteristic of producer organisms?

Back

Producers have an autotrophic lifestyle and produce reduced carbon compounds.

Front

Define nitrification in the nitrogen cycle.

Back

Nitrification is the biological process where ammonia is oxidized to nitrites (NO2-) and then to nitrates (NO3-) by nitrifying bacteria.

Front

What is the significance of ammonification in the nitrogen cycle?

Back

Ammonification is the process by which organic nitrogen is converted into ammonia by decomposers, making nitrogen available for uptake by plants.

Front

Explain the process of denitrification.

Back

Denitrification is the microbial process of reducing nitrates (NO3-) to nitrogen gas (N2), returning nitrogen to the atmosphere and completing the nitrogen cycle.

Front

What is the difference between assimilative and dissimilative nitrogen fixation?

Back

Assimilative nitrogen fixation incorporates nitrogen into organic molecules for growth, while dissimilative nitrogen fixation converts nitrogen into ammonia for energy without incorporation into organic matter.

Front

What are lithotrophic organisms?

Back

Lithotrophic organisms obtain energy by oxidizing inorganic substances, such as ammonia or sulfur compounds, rather than organic compounds.