Understanding Cell Behavior in Different Solutions

Let's analyze what happens to an animal cell when it's placed in a medium with a lower concentration of water. This situation relates to the process of osmosis, which is the movement of water across a semi-permeable membrane.

Osmosis and Water Concentration

Osmosis is essentially the diffusion of water molecules. Water moves from an area where its concentration is high to an area where its concentration is low, provided there is a semi-permeable membrane separating the two areas. The cell membrane of an animal cell acts as this semi-permeable membrane.

When we talk about water concentration in a solution, we usually compare it to the solute concentration. A solution with a higher concentration of solutes has a lower concentration of water, and vice versa.

Analyzing the Scenario: Animal Cell in a Low Water Concentration Medium

The question states that the animal cell is surrounded by a medium with a lower concentration of water. This means the concentration of solutes in the surrounding medium is higher than the concentration of solutes inside the animal cell. Such a solution is called a hypertonic solution.

What Happens in a Hypertonic Solution?

• The concentration of water inside the animal cell is relatively higher than the concentration of water outside the cell.
• Water molecules will move from the region of higher water concentration (inside the cell) to the region of lower water concentration (outside the cell) through the cell membrane by osmosis.
• This net movement of water out of the cell causes the cell to lose water.

Consequences for an Animal Cell

When an animal cell loses water, it shrinks. This process is called crenation. Animal cells do not have a rigid cell wall, so they cannot maintain their shape when water moves in or out significantly. Losing water causes the cell membrane to pull away from the cytoplasm, resulting in a shrunken appearance.

Evaluating the Options

Based on the understanding of osmosis and hypertonic solutions, let's look at the given options:

• Option 1: Cell will lose water - This is consistent with water moving out of the cell into the surrounding hypertonic medium.
• Option 2: No change in movement of water - This would only happen if the concentration of water inside and outside the cell were equal (an isotonic solution).
• Option 3: Cell will gain water - This happens when the surrounding medium has a higher concentration of water (a hypotonic solution).
• Option 4: Cell will swell up - Swelling occurs when the cell gains water (in a hypotonic solution), not when it loses water. Losing water causes shrinking.

Therefore, when an animal cell is surrounded by a medium with lower concentration of water (a hypertonic medium), the cell will lose water.

Summary of Cell Behavior in Different Solutions

Let's summarize how animal cells behave in different types of solutions:

In this specific question, the medium has a lower concentration of water, which is a hypertonic solution. In a hypertonic solution, the animal cell loses water.

Revision Table: Cell in Different Media

Here's a quick table to help revise the concepts related to osmosis and animal cells:

Additional Information: Why Animal Cells are Different

It's important to note that plant cells behave slightly differently because they have a rigid cell wall outside the cell membrane. In a hypertonic solution, a plant cell also loses water and the cell membrane shrinks away from the cell wall (plasmolysis), but the cell wall maintains the overall shape. In a hypotonic solution, plant cells swell and become turgid due to the cell wall preventing them from bursting.

Understanding the role of the cell wall is key to differentiating between the behavior of animal and plant cells in different osmotic environments.