Uchechi+Nwegbo+-+11+Transport+in+Cells-S - Transport in Cells 1 ... - Free Printable

Let's go through the "Transport in Cells" worksheet step by step and solve each question, explaining the reasoning clearly.

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Model 1 – Movement of Water In and Out of Cells

The diagram shows:
- A selectively permeable membrane (dashed line) surrounding a cell.
- Sugar molecules (solute): represented by circles (○).
- Water molecules (solvent): represented by plus signs (+).
- Arrows show the movement of water across the membrane.

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Question 1: Identify the solute and solvent

> A solution consists of a solute and a solvent mixed together. For the solution in Model 1, identify and provide the symbol for:

#### a. Solute
- The solute is the substance dissolved in the solvent.
- In this case, sugar molecules are dissolved in water.
- Symbol: ○

✔ Answer: The solute is the sugar molecules, symbolized by ○.

#### b. Solvent
- The solvent is the medium in which the solute dissolves.
- Here, water is the solvent.
- Symbol: +

✔ Answer: The solvent is the water molecules, symbolized by +.

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Question 2: Which molecules can move through the membrane?

> Consider the size of the sugar and water molecules in Model 1. Which molecules in the diagram are able to move through the selectively permeable membrane?

- The selectively permeable membrane allows small molecules like water to pass through but blocks larger molecules like sugar.
- Water molecules (+) are small and can move freely.
- Sugar molecules (○) are larger and cannot pass through the membrane.

✔ Answer: The water molecules are able to move in and out of the membrane.

> (Note: This process is called osmosis — the movement of water across a semi-permeable membrane from an area of lower solute concentration to an area of higher solute concentration.)

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Question 3: Complete the table by counting molecules

We need to count the number of sugar and water molecules inside and outside the cell based on the diagram.

Let’s carefully analyze the diagram:

#### Inside the Cell:
- Count the circles (○) = sugar molecules → 6
- Count the plus signs (+) = water molecules → 24

#### Outside the Cell:
- Count the circles (○) = sugar molecules → 15
- Count the plus signs (+) = water molecules → 15

Now calculate the ratio of water to sugar:

- Inside:
Water : Sugar = 24 : 6 = 4:1

- Outside:
Water : Sugar = 15 : 15 = 1:1

✔ Completed Table:

| | Inside the Cell | Outside the Cell |
|------------------------|---------------------|----------------------|
| Number of sugar molecules | 6 | 15 |
| Number of water molecules | 24 | 15 |
| Ratio of water to sugar | 4:1 | 1:1 |

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✔ Final Answers Summary:

#### 1. a. Solute: Sugar molecules, symbol: ○
#### 1. b. Solvent: Water molecules, symbol: +

#### 2. Water molecules (+) are able to move through the selectively permeable membrane.

#### 3. Table:
| | Inside the Cell | Outside the Cell |
|------------------------|------------------|-------------------|
| Sugar molecules | 6 | 15 |
| Water molecules | 24 | 15 |
| Water to sugar ratio | 4:1 | 1:1 |

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🔍 Key Concept: Osmosis

- Since there are more sugar molecules outside the cell, the concentration of solutes is higher outside.
- Water moves from low solute concentration (inside) to high solute concentration (outside) via osmosis.
- This will cause the cell to lose water and possibly shrink (crenation), unless the system is balanced.

This model illustrates osmosis and how cells regulate water balance through passive transport.

Let me know if you'd like to continue with further questions or explain what happens next!