Osmosis

Osmosis

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Vocabulary: Osmosis

Osmosis involves the movement of water molecules across a cell membrane without the use of energy.

The semipermeable membrane

Water is a very small molecule, so it can pass through the semipermeable membrane of a cell. Water can also move through through protein channels in the cell membrane.

Osmosis

Since water molecules will move with the concentration gradient, no energy is used through the process of osmosis.

Video Segments

You will watch 3 video segments from the Amoeba Sisters' video, Osmosis and Water Potential. Begin each video segment by clicking on the preview image.

Multiple Choice

Salt is used on roads because it

• is a good way to kill plants

• changes the freezing temperature of snow and ice to make roads less dangerous

• is a way to dispose of surplus (extra) salt

Multiple Choice

Osmosis uses no energy, making it

• passive transport

• active transport

Multiple Choice

Water naturally moves from

• low concentration of water to high concentration of water

• high concentration of water to low concentration of water

Hyper- means above or beyond, "extra".

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A hypertonic solution has a high concentration of salt, sugar, or another solute and causes cells to shrivel up as water moves out of the cell. ​

Hypertonic

Hypo- means under or low. A hypotonic solution has a low concentration of salt, sugar, or other solute.

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In a hypotonic solution, water moves into cells and they can burst.​

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Hypotonic

Iso- means equal.

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An isotonic solution has the same concentration as the cell, so an equal number of water molecules move in and out of the cell.

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Isotonic solutions help cells stay healthy.​

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Isotonic

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Multiple Choice

A solvent with high solute (sugar, salt) concentration is ___________ to water

• hypotonic

• isotonic

• hypertonic

Multiple Choice

A hypotonic solution has a _________ concentration of solute.

• low

• high

Multiple Choice

A hospital IV is ______________ to human blood.

• hypertonic

• isotonic

• hypotonic

Multiple Choice

Water enters plant roots through

• active transport

• osmosis

Multiple Choice

Turgor pressure helps plants to maintain structure.

• True

• False

Using osmosis to maintain your smile

In the next video, a dentist explains how salt and baking soda can keep your mouth healthy by killing bacteria and amoebas.

Multiple Choice

A salt rinse kills dental bacteria and amoebas because

• the bacteria and amoebas lose too much water

• the bacteria and amoebas absorb too much water