GED Science TestLife ScienceHard
A farmer notices that a particular variety of corn planted in a specific field consistently yields smaller cobs and fewer kernels compared to the same variety planted in other fields on his farm. Soil analysis reveals that the problem field has significantly lower levels of nitrogen. Which of the following biological processes is most directly impaired by this nitrogen deficiency, leading to reduced corn yield?
- ACellular respiration, due to insufficient energy storage.
- BPhotosynthesis, due to lack of chlorophyll production.
- CWater absorption, due to impaired root development.
- DProtein synthesis, essential for growth and enzyme production.
Show answer & explanationAnswer & explanation
Correct answer: D. Protein synthesis, essential for growth and enzyme production.
Nitrogen is a crucial component of amino acids, which are the building blocks of proteins. Proteins, in turn, are essential for plant growth, enzyme production, and many other vital cellular functions. A deficiency directly impairs protein synthesis, leading to stunted growth and reduced yield.
Why the other options are wrong
- A. Cellular respiration requires sugars (from photosynthesis) and oxygen; while overall plant health impacts it, nitrogen's direct role isn't primarily in energy storage or respiration itself.
- B. While nitrogen is part of chlorophyll, and its deficiency can impact photosynthesis, its most direct and fundamental role, underpinning overall growth, is in protein synthesis.
- C. While severe nutrient deficiencies can indirectly affect root development, nitrogen's primary role is not directly in water absorption.
Nitrogen's Role in Plants
Nitrogen is a macronutrient essential for plant growth and development, playing a critical role in the synthesis of amino acids, proteins, nucleic acids (DNA/RNA), chlorophyll, and ATP.
- Component of amino acids, the building blocks of proteins.
- Crucial for enzyme production and metabolic processes.
- Essential for chlorophyll synthesis (photosynthesis).
- Required for DNA and RNA synthesis (genetic material and protein synthesis machinery).
Memory trick: No Nitrogen, No New Proteins, No Notable Growth.