Question

During osmosis, flow of water through a semipermeable membrane is (a) from both sides of semi-permeable membrane with unequal flow rates (b) from solution having lower concentration only (c) from solution having higher concentration only (d) from both sides of semi-permeable membrane with equal flow rates

Short answer

The correct answer is (b): from solution having lower concentration only.

Step-by-step solution

Understanding the Concept of Osmosis

Osmosis is the movement of water across a semipermeable membrane. It occurs in order to balance the concentration of solutes on either side of the membrane. The water moves from the side with a lower concentration of solute (higher concentration of water) to the side with a higher concentration of solute (lower concentration of water). This is important for understanding the direction of water flow.

Statement Analysis

Let's analyze each given option to determine which accurately depicts osmosis: (a) suggests water flows from both sides with unequal flow rates. (b) suggests water flows only from a solution having a lower concentration. (c) suggests water flows only from a solution having a higher concentration. (d) suggests water flows from both sides with equal flow rates.

Applying Osmosis Definition

Given the movement explained in osmosis, water moves from an area of low solute concentration to an area of high solute concentration. This means water doesn't flow equally from both sides (ruling out a and d), nor does it move from higher concentration (ruling out c). It moves from lower to higher solute concentration (supporting option b).

Conclusion

The correct answer is option (b): water flows through a semipermeable membrane from a solution having lower concentration to a solution having higher concentration.

Key concepts

Semipermeable Membrane

A semipermeable membrane is a special barrier that allows certain molecules or ions to pass through it by diffusion. It is like a filter that selectively permits substances based on size or type. Water molecules, which are small, can easily penetrate this barrier, while larger molecules such as sugar or proteins might not pass through as easily.
This membrane's selective nature plays a crucial role in biological systems, maintaining homeostasis. Essentially, semipermeable membranes help cells control their internal environments by managing what enters or exits.
In the context of osmosis, these membranes allow water to move through while keeping crucial larger molecules static, ensuring that osmotic pressure can help balance conditions inside and outside of cells.

Water Movement

Water movement in the process of osmosis is a key aspect of cellular function. This movement is solely driven by differences in concentration across a semipermeable membrane. Here's how it typically works:

• Water moves from an area where it is in high concentration (fewer solutes) to an area where it is in low concentration (more solutes).
• Osmosis facilitates balance, where the water equalizes solute concentrations on each side of the membrane by moving to the side with the higher concentration of solutes.

This process helps cells acquire needed nutrients and expel waste, enabling growth and survival. It's like a balancing act, where water adjusts to create a stable internal and external environment. Understanding water movement is vital for grasping how cells, and thus organisms, sustain life.

Concentration Gradient

A concentration gradient is essentially a difference in the number of solute particles in two regions. This gradient is the driving force for passive transport processes like osmosis. When there is a concentration difference, molecules move from an area of higher concentration to an area of lower concentration, seeking equilibrium. In the context of osmosis, however, water moves towards where there are more solute particles; that is, from low to high solute concentration.
This movement against the solute concentration ensures that both compartments separated by a membrane achieve more balanced conditions. In biology, managing concentration gradients is crucial for functions like nutrient absorption, waste removal, and maintaining proper cell shape and function.
These gradients are essential for sustaining cellular activity and overall organism health, making understanding them a core part of learning about osmosis and cellular dynamics.