Plant and Animal Cell Tonicity

Plant and Animal Cell Tonicity

Let's explore what happens to plant and animal cells in different solutions!

Tonicity Review

There are three different types of solutions: hypertonic, isotonic, and hypotonic. 

Don't forget that when solutions of different concentrations are separated by a membrane permeable to water, the water will move from the side with lower concentration  to the side with higher concentration.

Take a closer look...

• When the concentration on the INSIDE of the cell is higher, the water will move into the cell, causing the cell to swell. (Hypotonic)

• When the concentration on the OUTSIDE of the cell is higher, the water will move out of the cell, causing the cell to shrink. (Hypertonic)

• When the concentration on the inside of the cell is the SAME as the outside, the water will move in and out of the cell, causing no change to the cell. (Isotonic)

Here are the three types of solutions!

But what do plant and animal cells look like when they are put in different solutions?

Let's find out!

Animal Cells

• A hypertonic solution causes water to move out of the cell and the cell becomes shriveled. Red blood cells develop a star-shaped appearance that resembles a spiked ball (they become crenated).

• An isotonic solution does not result in any net movement of water in/out of the cell and so it remains unaffected.

• A hypotonic solution causes water to move into the cell. Animal cells do not have a tough cellulose wall and if water continues to move into the cell pressure builds until ultimately the cell bursts (cell lysis)

Multiple Choice

Which picture below shows an animal cell, like a red blood cell, that has been placed in a Hypotonic Solution?

Plant Cells

• A hypertonic solution causes water to move out of the cell and the cell membrane tears away from the cell wall in a process called plasmolysis.

• An isotonic solution does not result in any net movement of water in/out of the cell, however, a plant cell may become flaccid (wilted).

• A hypotonic solution causes water to move into the cell. The cell wall limits the cell’s volume preventing it from bursting. However, the plant cells to become turgid (swollen and firm). 

Multiple Choice

What type of solution should you put fresh flowers in to keep them fresh the longest?

• Hypertonic- It causes plasmolysis, which causes the flowers to turgid.

• Hypotonic- It causes the cell membrane to push on the cell wall, causing the flowers to stay turgid.

• Isotonic- It causes the flowers to become flaccid.

• Neutral solution- It will not cause any change in the flowers

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Multiple Choice

What happens when a plant cell becomes flaccid?

• The plant becomes stiff or turgid due to an increase in cell pressure.

• There is more structure to the cells

• The plant cells bursts

• The plant becomes wilted because of a loss of cell pressure.

Poll

How are you feeling about this lesson?

• Great! Easy stuff.

• Eh. It's alright, but I probably need more practice.

• Yikes. I kind of know what's going on, but not really.

• Wait, I'm taking biology?!