Biology Osmosis Chapter 1.3.2

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Questions and Answers

What drives the movement of water during osmosis?

Movement from areas of high water potential to low water potential. (correct)

Active transport requiring cell energy.

Movement from areas of high solute concentration to low solute concentration.

Movement from areas of low water potential to high water potential.

A cell is placed in a solution where the concentration of solutes is lower than inside the cell. What is the correct term to describe this type of solution?

Isotonic

Hypertonic

Hypotonic (correct)

Equilibrium

Which of the following best describes the nature of osmosis through a cell membrane?

A passive process where water moves through a channel protein.

An active process that requires transport proteins to move water.

Requires energy to move water through the membrane against the concentration gradient

An energy-free process where water moves down its concentration gradient. (correct)

If a cell is placed in a hypertonic solution, what will be the net movement of water?

Water will move out of the cell. Signup and view all the answers

Which of the following scenarios will result in no net movement of water across a cell membrane by osmosis?

The concentration of solutes inside and outside the cell are equal. Signup and view all the answers

What happens to a plant cell when it is placed in a hypotonic solution?

The cell swells, and turgor pressure increases. Signup and view all the answers

If a potato tuber cylinder increases in mass when placed in a sugar solution, what does this indicate about the solution?

The solution was hypotonic to the potato cells. Signup and view all the answers

What is the primary role of turgor pressure in plant cells?

Providing structural support and rigidity. Signup and view all the answers

What will happen to an animal cell if it is placed in distilled water (a very dilute solution)?

The cell will burst due to excess water intake. Signup and view all the answers

What term describes a solution that causes water to move out of a cell?

Hypertonic Signup and view all the answers

What is the correct term for when the cell membrane moves away from the cell wall in a plant cell due to water loss?

Plasmolysis Signup and view all the answers

In a model with a partially permeable membrane bag containing sugar solution placed in external solutions, what does the level of water in the tube indicate?

The movement of water in and out of the bag by osmosis. Signup and view all the answers

If a cell is placed in an isotonic solution, what is the expected net movement of water?

No net movement of water. Signup and view all the answers

Study Notes

Osmosis (1.3.2)

Osmosis is the movement of water across cell membranes from a less concentrated solution to a more concentrated solution through a partially permeable membrane.
Water moves from an area of high water potential to an area of low water potential.
This process is passive, meaning it does not require energy.
A dilute solution has a high water potential and a high concentration of water.
A concentrated solution has a low water potential and a low concentration of water.

Modeling Osmosis

The cytoplasm of a cell contains salts and sugars.
A cell placed in a dilute solution will have water move into the cell.
This can be modeled using a partially permeable membrane bag containing sugar molecules with a glass tube.
The bag can be placed in solutions of varying concentrations to observe water movement.

Types of Solutions

Isotonic: The concentration of sugar in the external solution is the same as the internal concentration. No net movement of water.
Hypertonic: The concentration of sugar in the external solution is higher than the internal concentration. Water moves out of the cell.
Hypotonic: The concentration of sugar in the external solution is lower than the internal concentration. Water moves into the cell.

Osmosis in Animals

If the external solution is more dilute (higher water potential), water moves into animal cells, causing them to burst.
If the external solution is more concentrated (lower water potential), water moves out of the animal cells, causing them to shrivel.

Osmosis in Plants

If the external solution is more dilute, water moves into plant cells, causing them to swell and maintain turgor pressure (essential for plant rigidity).
If the external solution is less dilute, water moves out of plant cells, causing them to become soft, eventually leading to plasmolysis (cell membrane separation from the cell wall).

Experiment: Effect of Sugar Solutions on Plant Tissue

Placing potato tubers in different sugar solutions affects their mass as water moves in or out.
Measuring the mass before and after placement allows for determining whether the external solution or the potato had a higher concentration.
Calculating the percentage change in mass and plotting it on a graph reveals the relationship between the concentration of the sugar solution and the mass change of the potato.

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Description

Explore the fascinating process of osmosis in this quiz. Understand how water moves across cell membranes, the impact of different solutions, and the significance of water potential. Test your knowledge on modeling osmosis and the types of solutions involved.