Question

Diffusion can occur between (a) One part of cell to other part (b) Cell to cell (c) Intercellular space to outside of leaf (d) All of these

Short answer

The correct answer is (d) All of these. Diffusion can occur in all the given situations.

Step-by-step solution

Analyzing Each Option

(a) One part of cell to other part: Diffusion can certainly occur from one part of a cell to another part, because inside a cell, molecules move from areas of higher concentration to areas of lower concentration. (b) Cell to cell: Diffusion can also happen from cell to cell. For example, water and nutrients can diffuse from one cell to others through their cell walls. (c) Intercellular space to outside of leaf: Gases like oxygen and carbon dioxide diffuse from the intercellular spaces to the outside of the leaf through the stomata, microscopic pores on the leaf. (d) All of these: As discussed, diffusion can occur in all the mentioned scenarios.

Finalizing the Answer

Considering the process of diffusion and how it operates at the cellular level within a plant, it is apparent that diffusion can occur in all the scenarios provided in the exercise i.e. from one part of a cell to another, from cell to cell, and from intercellular spaces to the outside of a leaf. Thus, the correct option is (d) All of these.

Key concepts

Cellular Diffusion in Plant Cells

Cellular diffusion is a fundamental process by which molecules move within plants. This passive transport mechanism does not require energy, relying instead on the natural movement of particles from an area of high concentration to an area of lower concentration to achieve balance or equilibrium.

In the context of plant cells, diffusion allows for the distribution of vital substances like water, oxygen, and nutrients. It can occur within the cytoplasm of a single cell, where it aids in the equal distribution of molecules, ensuring that all parts of the cell have access to necessary components for metabolism and growth.

Additionally, diffusion is significant in the movement of molecules from cell to cell. Plant cells, surrounded by rigid cell walls, connect through microscopic channels called plasmodesmata, which permit the transfer of small molecules and ions directly from the cytoplasm of one cell to that of its neighbor.

Stomata Gas Exchange

Stomata, the tiny openings found predominantly on the undersides of leaves, play a crucial role in plant respiration and photosynthesis. These openings can open and close in response to environmental conditions and are surrounded by guard cells that regulate their aperture.

Through the process of gas exchange, carbon dioxide (CO₂) diffuses into the leaf, while oxygen (O₂) and water vapor (H₂O) diffuse out. This movement is vital for photosynthesis, during which plants convert light energy into chemical energy, producing the oxygen we breathe and the glucose that provides energy for the plant.

The stomata's opening and closure are essential in preventing excessive water loss through transpiration, while still allowing gas exchange. Therefore, the stomatal control of gas exchange is a fine-tuned balance between allowing sufficient CO₂ in for photosynthesis and minimizing water loss.

Concentration Gradient

The term 'concentration gradient' refers to the variation in the concentration of a solute in a solution or gas in a mixture across different spaces. In the context of plants and diffusion, it represents the difference in concentration of molecules inside the plant's cells compared to their surroundings.

This gradient is the driving force behind the diffusion process. Molecules will spontaneously move down their concentration gradient, from areas of high concentration to areas of lower concentration, until equilibrium is reached.

For example, inside the leaf, high concentrations of carbon dioxide may build up during photosynthesis. When the stomata are open, the concentration gradient between the high levels of CO₂ inside the leaf and lower levels outside drives CO₂ out of the leaf. Conversely, the typically lower concentration of CO₂ in the air outside the leaf compared to inside drives CO₂ into the leaf through the stomata—demonstrating how the concentration gradient influences the direction and rate of diffusion.