Which one of the following statements about transport mechanism in plants is correct?

Transport mechanisms in plants and other organisms are categorized into passive and active processes. Diffusion is a passive process where ions and small molecules move down a concentration gradient (from high to low concentration) without the expenditure of energy [3]. In contrast, active transport involves the movement of molecules or ions against their concentration gradient (from low to high concentration) [3]. This process requires metabolic energy, typically in the form of ATP, to power membrane proteins or pumps [3]. For instance, plant roots actively take up ions from the soil, creating a concentration difference that facilitates water movement [1]. While some small molecules like oxygen and carbon dioxide diffuse freely, charged ions often require specific channels or energy-driven pumps to cross the hydrophobic cell membrane. Therefore, statement 2 is correct as active transport against a gradient necessitates energy.

Sources

1. [3] https://www.ncbi.nlm.nih.gov/books/NBK547718/
2. [2] Science , class X (NCERT 2025 ed.) > Chapter 5: Life Processes > ATP > p. 88
3. [1] Science , class X (NCERT 2025 ed.) > Chapter 5: Life Processes > Transport of water > p. 94