Why is active transport necessay in the process of moving food molecules within a plant?
Diffusion (molecules moving about by a randown walk process bumping into each other) is too slow. They must be transported in a moving stream of fluid.
Thankyou :)
Active transport is necessary in the process of moving food molecules within a plant because it allows the plant to selectively take up and distribute essential nutrients against their concentration gradient. Unlike passive transport, which moves molecules from an area of higher concentration to lower concentration, active transport requires energy to move molecules against their concentration gradient.
To understand why active transport is necessary for moving food molecules, let's consider the process of nutrient absorption by plant roots. Plant roots absorb water and dissolved nutrients from the soil through their root hairs. While water can pass through the root cell membranes easily by osmosis, certain ions and molecules, such as mineral nutrients, cannot diffuse across the cell membrane without assistance.
In order to absorb these essential nutrients against their concentration gradient (from the soil to the root cells), plants employ active transport mechanisms. This process involves the use of specialized proteins called pumps or carriers embedded in the cell membrane. These pumps actively transport specific nutrients, such as nitrate, phosphate, potassium, and iron, into the root cells using energy derived from ATP (adenosine triphosphate).
By actively transporting nutrients into the root cells, plants can accumulate essential compounds in their tissues, even when the concentration in the soil is low. This selective uptake of nutrients allows plants to maintain proper growth, development, and metabolism.
Furthermore, active transport is also involved in the distribution of food molecules throughout the plant. Once nutrients are absorbed by the roots, they need to be transported to other parts of the plant, such as leaves, stems, and fruits, where they are utilized for growth and energy production. Active transport processes in specialized tissues, such as xylem and phloem, help in the movement of these nutrients to the desired locations.
In summary, active transport is necessary in the process of moving food molecules within a plant because it enables the plant to overcome concentration gradients and selectively absorb essential nutrients from the soil. It also allows for the distribution of these nutrients to different parts of the plant, ensuring proper growth and metabolism.