Nursing Entrance Exam (NEX) Practice Exam

Which of the following statements about chlorophyll production in corn is true?

1. It is always present in all corn plants

2. It can be absent due to recessive traits

3. It results only from environmental factors

4. It is essential for seed germination

The correct answer is: It can be absent due to recessive traits

Chlorophyll production in corn can indeed be absent due to recessive traits. This occurs because the presence of chlorophyll is determined by the plant's genetic makeup. Specifically, if a corn plant carries two recessive alleles for chlorophyll production, it may not produce the pigment at all, leading to plants that are yellow or white instead of the usual green. This genetic influence highlights how traits can be inherited and how the variability in these traits can affect the appearance and health of corn plants. Understanding this genetic basis is crucial for plant science and agriculture. The other statements do not accurately reflect the nature of chlorophyll production. For instance, while chlorophyll is typically found in healthy corn plants, it is not universally present in all cases, particularly in plants expressing recessive traits. Additionally, while environmental factors can influence chlorophyll levels (like light and nutrient availability), they are not the sole determinants, as genetic factors play a significant role. Chlorophyll is not directly essential for seed germination either; seeds can germinate and sprout even if they later don't produce chlorophyll, although chlorophyll is important for photosynthesis in the plant's growth phase.