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Turgor Pressure

Plants without water…what happens?

What is it?

Turgor Pressure

• Water-filled vacuoles push against cell walls of a plant. This creates a pushing force called turgor pressure.

• Why it’s important:Together, the cell wall and the water-filled vacuole provide structural support for plants.

Plants stand upright because of turgor pressure, the force of

water pressing against their cell walls.

Turgor Pressure

http://www.youtube.com/watch?v=fhsurzE_-J0

On the left: lots of water

On the right: not enough water

(Notice the change in the vacuole)

Balloons….

Draw this:

XylemCarries water and minerals from the roots through the stem and leaves

The Xylem themselves are a STRUCTURAL adaptationThe carrying of water is a PHYSIOLOGICAL adaptation: some plants carry the water faster than others….

Let’s explore how the Xylem works in celery and carnations

Dehydration

• Salt and sugar can act as dehydrators: taking water out of the cell

• If they are added to a plant cell, what do you think will happen?

• Let’s see. Cucumbers…….

Now let’s explore using a slice of potatoWrite the lab in your ISN….

• Question: How will a salt solution affect a potato?

Hypothesis:Choose a hypothesis below and write it in your journal.

• If a potato slice is placed in salt water then it will become flexible because the vacuoles in the cells have dehydrated.

OR• If a potato slice is placed in salt water then it

will become smaller because the vacuoles in the cells have dried out.

ACAD

Copy the chart into your journal

Experiment: Water Type Mass before Mass After Observations

Salt Water

Distilled Water

Hypothesis: • If we put the potato slice in salt water then

________ will happen because __________.

Experiment:

Pre-AP

Water Type Mass before Mass After Observations

Salt Water

Distilled Water

While we wait…

• http://www.youtube.com/watch?v=fNyYuVarTIQ• http://www.youtube.com/watch?v=qrp7V0Q5qY

Q

• https://www.youtube.com/watch?v=d26AhcKeEbE&list=PLE720771409B9EF4A&index=3

https://www.youtube.com/watch?v=fhsurzE_-J0

While we wait…Forces in Living Systems• The teeth apply force in breaking food into

smaller pieces• Muscles in the esophagus exert a force in

pushing food down the digestive tract through peristalsis

• Muscles contract and relax, creating a enough force to move bones to walk, run, jump or engage in other life processes

• The heart supplies the force that causes blood to flow through blood vessels.

Analysis: 1. What did you notice about the potato in the salt

water?

2. How did this happen?

3. What happens when a plant wilts?

Conclusion: summaryTell me if your hypothesis was valid or invalid. Explain

why!

Show your teacher your journal when you are done to receive your stamp