Question

What will happen to a blood cell that is placed in pure water?

Short answer

A blood cell placed in pure water will swell and can burst due to the influx of water from the hypotonic pure water into the hypertonic blood cell, a process driven by osmosis.

Step-by-step solution

Understand Osmosis

Osmosis is the movement of water from an area of low solute concentration (hypotonic solution) to an area of high solute concentration (hypertonic solution) through a semi-permeable membrane.

Identify the Hypotonic and Hypertonic Regions

In this case, pure water is the hypotonic solution (low solute concentration) and the blood cell is the hypertonic solution (high solute concentration).

Analyze the Effect of Osmosis

Because of osmosis, the water molecules in the pure water will move into the blood cell, a hypertonic medium, in an attempt to balance the solute concentration on both sides of the blood cell membrane.

Predict the Outcome

Given that the cell membrane is semi-permeable, it will allow the free movement of water until an isotonic state (equal concentration) is achieved. However, since the pure water outside the cell has almost no solutes, water will continue to flow into the cell. This can cause the cell to expand beyond its capacity and potentially several rupture or hemolysis. This is why it's potentially dangerous to infuse pure water directly into the bloodstream.

Key concepts

Hypotonic Solution

Imagine placing a gummy bear in a cup of water and watching it swell up after some time. In the realm of biology, a similar process occurs when cells interact with a hypotonic solution. This type of solution has a lower concentration of solutes compared to the inside of the cell. When a cell, such as a blood cell, encounters a hypotonic environment like pure water, water rushes into the cell. This is due to a natural phenomenon called osmosis, where water travels from an area with low solute concentration to one with high solute concentration.

• A hypotonic solution causes cells to swell as water moves inward.
• This can be beneficial for rehydrating cells, but dangerous if uncontrolled.
• Understanding the effects of hypotonic solutions is crucial in medical treatments to avoid cell damage.

This dynamic is essential for maintaining cell hydration but can have adverse effects if not regulated properly, such as cellular swelling or even bursting, which we'll discuss later as cell lysis.

Hypertonic Solution

On the flip side, if you've ever sprinkled salt on a slug, you have witnessed the effects of a hypertonic solution. These solutions possess a higher concentration of solutes compared to the inside of a cell. If a cell is placed in a hypertonic environment, water will leave the cell in an attempt to equalize solute concentrations on each side of the cell membrane.

• Hypertonic solutions lead to cell shrinkage or crenation due to water loss.
• They are often used in medical settings to reduce swelling by drawing fluids out of cells.
• The understanding of hypertonic solutions helps manage conditions like edema where fluid accumulation occurs in tissues.

The osmotic balance between hypotonic and hypertonic solutions is a delicate dance essential for cell health and function.

Semi-permeable Membrane

Acting as the gatekeeper, a semi-permeable membrane is a selective barrier that lets certain substances pass while blocking others. In biological cells, this membrane allows nutrients to enter, wastes to exit, and maintains the essential balance of ions and molecules.

• It is a critical component in processes like osmosis and dialysis.
• The semi-permeable nature ensures that cells can regulate their internal environment.
• Dysfunction or damage to this membrane can lead to severe cellular consequences.

The semi-permeable nature of the cell membrane plays a pivotal role in osmosis, where it allows water to pass freely in response to solute concentration gradients but typically restricts the movement of larger or charged solutes.

Cell Lysis

Cell lysis is the breakdown or bursting of a cell caused by external or internal forces. In the context of osmosis, a cell placed in a hypotonic solution can swell to the point where the mechanical stress exceeds the membrane's strength, resulting in the cell rupturing or undergoing lysis.

• Cell lysis can release contents that may be harmful to the surrounding tissues.
• In medical treatments, avoiding lysis is crucial; for example, intravenous solutions must be isotonic to prevent red blood cell lysis.
• Understanding cell lysis is also important in laboratory settings, such as when isolating cellular components for analysis.

Preventing cell lysis is a critical consideration in many applications, from medical treatments to food preservation and beyond, emphasizing the importance of managing osmotic pressures.