[Campbell Biology P.864] According to the provided information, which statement best describ... | Practice Question

According to the provided information, which statement best describes how plants primarily acquire and process nitrogen from the soil?

  • A: Plants directly absorb large amounts of NH3, which is then converted into amino acids.
  • B: Plants primarily absorb NO3- from the soil, which is then reduced back to NH4+ internally before being incorporated into organic compounds.
  • C: Plants mainly absorb N2 from the atmosphere through their roots, converting it directly into organic compounds.
  • D: Plants acquire both NO3- and NH4+ in equal amounts, incorporating them directly into proteins.

Explanation

The text states: 'Plants commonly acquire nitrogen in the form of NO3- nitrate ... After the roots absorb NO3-, a plant enzyme reduces it back to NH4+, which other enzymes incorporate into amino acids and other organic compounds.' The figure's caption also notes that plants 'absorb mainly nitrate, which is produced from ammonium by nitrifying bacteria. Plants reduce nitrate back to ammonium before incorporating the nitrogen into organic compounds.'