Osmosis worksheet with questions and diagrams illustrating water movement in cells and plant roots.

Problem Analysis and Solution

The worksheet focuses on the concept of osmosis, which is the movement of water across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration. Let's solve each question step by step.

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#### Question 1: Why wouldn't bacteria be able to survive on salted fish? Explain using the concept of osmosis.

- Explanation: Salted fish has a high concentration of salt (solute) in its tissues. When bacteria come into contact with this environment, the water inside the bacterial cells will move out of the cells due to osmosis. This happens because the solute concentration outside the bacterial cells (in the salted fish) is much higher than inside the bacterial cells.
- Result: The bacterial cells lose water and shrink, a process called plasmolysis. This dehydration can lead to the death of the bacteria.
- Answer: Bacteria cannot survive on salted fish because the high salt concentration causes water to move out of their cells via osmosis, leading to cell shrinkage and ultimately death.

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#### Question 2: The cells in the beakers shown below are permeable to water only. Indicate the tonicity of each solution (isotonic, hypotonic, or hypertonic) AND indicate the direction of water movement (into the cell, out of the cell, or no net movement of water).

- Beaker A:
- Tonicity: Hypertonic (more solute outside the cell than inside).
- Water Movement: Out of the cell (water moves from the cell to the surrounding solution to equalize the solute concentration).

- Beaker B:
- Tonicity: Isotonic (equal solute concentration inside and outside the cell).
- Water Movement: No net movement of water (the concentrations are balanced).

- Beaker C:
- Tonicity: Hypotonic (less solute outside the cell than inside).
- Water Movement: Into the cell (water moves into the cell to equalize the solute concentration).

- Answer:
- Tonicity of Solution:
- Beaker A: Hypertonic
- Beaker B: Isotonic
- Beaker C: Hypotonic
- Direction of Water Movement:
- Beaker A: Out of the cell
- Beaker B: No net water movement
- Beaker C: Into the cell

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#### Question 3: The roots of a plant have cells that absorb water from the soil. There is a high concentration of minerals inside the root cells compared to the minerals in the soil.

##### Part (a): Explain why water moves from the soil into the root hair cell.

- Explanation: The root hair cells of a plant have a higher concentration of solutes (minerals) inside them compared to the soil solution. According to the principle of osmosis, water will move from an area of lower solute concentration (soil) to an area of higher solute concentration (root hair cells).
- Answer: Water moves from the soil into the root hair cell because the soil solution is hypotonic relative to the root hair cells, causing water to move into the cells to balance the solute concentrations.

##### Part (b): Complete each sentence below.

1. The soil is _______ compared to the root cells.
- Answer: Hypotonic
- Reasoning: The soil has a lower solute concentration than the root cells.

2. The root cells are _______ compared to the soil.
- Answer: Hypertonic
- Reasoning: The root cells have a higher solute concentration than the soil.

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#### Question 4: Soft drinks may contain various concentrations of solutes. Some soft drinks have a low solute concentration and are a source of water for your body's cells. Others have a high solute concentration and can dehydrate your cells. Which of these drinks should be marketed as "thirst quenchers"? Explain your answer in terms of water concentration and water movement.

- Explanation:
- Low Solute Concentration (Thirst Quenchers): Drinks with a low solute concentration are hypotonic relative to the body's cells. When consumed, they cause water to move into the cells, hydrating them and relieving thirst.
- High Solute Concentration (Dehydrating): Drinks with a high solute concentration are hypertonic relative to the body's cells. When consumed, they cause water to move out of the cells, leading to dehydration.

- Answer: Soft drinks with a low solute concentration should be marketed as "thirst quenchers" because they are hypotonic and promote water movement into the body's cells, effectively hydrating them.

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Final Answers:

1. Bacteria cannot survive on salted fish because the high salt concentration causes water to move out of their cells via osmosis, leading to cell shrinkage and death.

2. Tonicity of Solution:
- Beaker A: Hypertonic
- Beaker B: Isotonic
- Beaker C: Hypotonic
Direction of Water Movement:
- Beaker A: Out of the cell
- Beaker B: No net water movement
- Beaker C: Into the cell

3. (a) Water moves from the soil into the root hair cell because the soil solution is hypotonic relative to the root hair cells.
(b)
- The soil is hypotonic compared to the root cells.
- The root cells are hypertonic compared to the soil.

4. Soft drinks with a low solute concentration should be marketed as "thirst quenchers" because they are hypotonic and promote water movement into the body's cells, effectively hydrating them.

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Final Answer Box:

\[
\boxed{
\text{1. Bacteria cannot survive due to osmotic water loss.}
\text{2. Tonicity: A-Hypertonic, B-Isotonic, C-Hypotonic; Direction: A-Out, B-No net, C-In.}
\text{3. (a) Soil is hypotonic, root cells are hypertonic.}
\text{4. Low solute concentration drinks are thirst quenchers.}
}
\]