A Level Biology Practice Exam

What describes the apoplast route in plants?

1. Movement of fluids through xylem only

2. Movement of substances through cell walls and intercellular spaces by diffusion and into the cytoplasm by active transport

3. Transport of nutrients through phloem

4. Absorption of water through root hair cells

The correct answer is: Movement of substances through cell walls and intercellular spaces by diffusion and into the cytoplasm by active transport

The apoplast route is characterized by the movement of substances through the plant's cell walls and intercellular spaces. This process occurs via diffusion, allowing for the passive transfer of water and solutes without crossing the cell membranes until they reach their destination. Once substances reach certain areas, they may enter the cytoplasm through active transport mechanisms, which utilize energy to move substances against their concentration gradient. This route is crucial for plant physiology, especially in the movement of water and nutrients from the soil into the root system. The specificity of the apoplast route allows for efficient nutrient uptake as it can bypass the cellular membranes until absolutely necessary, facilitating quicker intake compared to other routes. Thus, it reflects a key aspect of how plants manage their nutrient and water absorption effectively.