Problem 8 - Biology Concepts and Applications

Question

Immerse a living human cell in a hypotonic solution, and water will tend to __________. a. diffuse into the cell b. diffuse out of the cell c. show no net movement d. move in by endocytosis

Step-by-Step Solution

Answer

a. diffuse into the cell

Step 1: Understand the Definition of a Hypotonic Solution

A hypotonic solution is one whose solute concentration outside the cell is lower than inside the cell. This means the water concentration is higher outside the cell than inside. In this environment, the movement of water is influenced by osmosis.

Step 2: Identify the Water Movement due to Osmosis

Osmosis is the process by which water diffuses across a semi-permeable membrane from an area of lower solute concentration (higher water concentration) to an area of higher solute concentration (lower water concentration). In this scenario, the cell is in a hypotonic solution, meaning water outside is more concentrated.

Step 3: Determine Where Water Will Flow

Since water moves from higher concentration to lower concentration, and the concentration of water is higher outside the cell, water will tend to diffuse into the cell to equalize the concentration of solutes on both sides of the cell membrane.

Key Concepts

Hypotonic Solution

A hypotonic solution is a type of environment where the concentration of solutes outside the cell is lower than inside the cell. This means there is more water outside the cell compared to the inside. Understanding the nature of solutions can help predict how cells will behave when they come in contact with these solutions. Hypotonic solutions have implications for cell survival and function. When cells are placed in such solutions, they can experience osmotic pressure changes that could lead to swelling or bursting if the water influx is uncontrolled.

Water Movement

Water movement across cell membranes is primarily driven by a process called osmosis. Osmosis is a natural phenomenon where water moves from areas of higher concentration to areas of lower concentration. This usually happens across a semi-permeable membrane, like the cell membrane.

• In a hypotonic solution, there is a higher water concentration outside.
• Water will naturally move into the cell to equalize the concentrations on both sides.

This movement of water into the cell can cause it to swell, which is important to consider in biological and medical contexts.

Cell Membrane

The cell membrane is a critical structure acting as a barrier between the cell's internal environment and the external world. It is semi-permeable, allowing some substances, like water, to pass through while blocking others. This permeability is vital for processes like osmosis, which enables the cell to regulate its internal conditions.
The cell membrane ensures that essential nutrients enter the cell and waste products are removed. In the context of osmosis, it allows water to move freely but regulates the passage of solutes, maintaining a balanced internal environment essential for the cell's survival.

Solute Concentration

Solute concentration refers to the amount of solutes (like salt or sugar) present in a solution compared to the amount of solvent, which is usually water. In a hypotonic solution, solute concentration is lower outside the cell than inside. This difference in concentration is what drives osmosis.
Cells continually work to maintain a delicate balance of solutes to ensure proper function.

• High solute concentration inside the cell attracts water to enter.
• This movement helps equalize concentrations but can also cause cellular tension.

Understanding solute concentration helps explain why cells behave differently in varied environments and is fundamental for the study of cellular processes.