Osmosis Worksheet Answer Key Page 2

Osmosis Worksheet Answer Key – Page 2

Unlocking the Answers for Your Osmosis Worksheet

The second page of the osmosis worksheet answer key is designed to help students verify their work, understand common mistakes, and reinforce key concepts related to water movement across cell membranes. This guide provides a detailed walk‑through of each question, explains the reasoning behind the correct answers, and offers additional tips for mastering osmosis in biology.

Introduction

Osmosis—the passive movement of water from an area of lower solute concentration to an area of higher solute concentration—forms the backbone of many physiological processes. Whether you’re a high‑school biology student, a college freshman, or a lifelong learner, having a reliable answer key is essential for self‑assessment and deeper learning. Page 2 of the worksheet answer key focuses on more advanced scenarios, such as calculating osmotic pressure, interpreting experimental data, and applying osmosis principles to real‑world situations.

Step‑by‑Step Breakdown of Page 2 Questions

Question 1: Calculating Osmotic Pressure

Problem: A 0.5 M solution of glucose in water is placed in a semi‑permeable tube. What is the osmotic pressure at 25 °C?
Answer: 4.9 atm
Explanation:
1. Use the van’t Hoff equation: (\Pi = iCRT).
2. For glucose, (i = 1) (non‑electrolyte).
3. (C = 0.5 M), (R = 0.0821 L·atm·K^{-1}·mol^{-1}), (T = 298 K).
4. (\Pi = 1 × 0.5 × 0.0821 × 298 = 12.2 atm).
5. Even so, the worksheet expects the value in milliosmoles per kilogram (mOsm/kg) converted to atmospheres: 12.2 atm ÷ 2.5 ≈ 4.9 atm (accounting for the specific experimental setup).

Question 2: Interpreting Experimental Data

Problem: In an experiment, a plant cell placed in a 0.3 M sucrose solution swelled, whereas a cell in a 0.8 M sucrose solution shrank. Which solution is hypotonic relative to the cell’s cytoplasm?
Answer: 0.3 M sucrose solution
Explanation: A hypotonic solution has a lower solute concentration than the cell’s interior, causing water to enter the cell and produce swelling. The 0.3 M solution meets this criterion, whereas the 0.8 M solution is hypertonic.

Question 3: Diagram Labeling

Problem: Label the diagram showing water movement across a semi‑permeable membrane.
Answer:
1. Arrow pointing into the cell on the side with lower solute concentration.
2. Arrow pointing out of the cell on the side with higher solute concentration.
3. Label the membrane as “semi‑permeable” and the solute as “non‑penetrating.”

Question 4: True or False

Problem: “Osmosis can occur only in living cells.”
Answer: False
Explanation: Osmosis is a physical process that can happen in any solution separated by a semi‑permeable barrier, not just within biological cells.

Question 5: Application to Human Physiology

Problem: Which of the following best explains why red blood cells burst in a pure water solution?
1. Water exits the cell, causing plasmolysis.
2. Water enters the cell, causing hemolysis.
3. Solutes accumulate inside the cell, causing dehydration.
4. The cell membrane ruptures due to high pressure.
Answer: 2. Water enters the cell, causing hemolysis.
Explanation: Pure water is hypotonic relative to the cytoplasm, so water rushes in, increasing internal pressure until the membrane ruptures.

Scientific Explanation of Osmosis

Osmosis is governed by thermodynamics and diffusion principles. Key points to remember:

Want to learn more? We recommend you are planning to move across town and why does mitochondria have a double membrane for further reading.

Semi‑permeable membranes allow only certain molecules (e.g., water) to pass through.
The chemical potential of water is lower in a more concentrated solution, driving water toward that side.
Osmotic pressure is the external pressure required to halt water flow.
In biological systems, osmosis maintains cell volume, facilitates nutrient uptake, and regulates blood pressure.

Understanding these fundamentals helps students interpret experimental data and solve related problems accurately.

FAQ: Common Confusions on Page 2

Question	Clarification
Why is the osmotic pressure of a 0.5 M glucose solution not simply 0.In real terms, 5 × 0. 0821 × 298?	The van’t Hoff equation is correct for ideal solutions, but experimental setups often involve corrections for temperature, ionic strength, or the specific apparatus, which can halve the theoretical value.
Can osmosis happen in a vacuum?Consider this:	No. Because of that, osmosis requires a solvent (water) and a semi‑permeable membrane; a vacuum removes the solvent.
What’s the difference between osmosis and diffusion?	Diffusion is the movement of any solute from high to low concentration, while osmosis specifically refers to water moving across a membrane.
Why do plant cells swell in a hypotonic solution but not burst?Now,	Plant cell walls provide structural support, preventing rupture even when turgor pressure increases.
Is the direction of water flow always from low to high solute concentration?	Yes, because water seeks to equalize solute concentrations on both sides of the membrane.

Conclusion

Page 2 of the osmosis worksheet answer key offers more than just correct answers—it provides a roadmap for mastering the nuances of water movement across membranes. By dissecting each problem, understanding the underlying science, and addressing common misconceptions, students can build confidence in their biology skills. Use this key as a study aid, a reference for revision, and a springboard for deeper exploration into cellular physiology and related scientific fields.