2025 NEW BIO 201L Lab 4 Diffusion and Osmosis COMPLETE UPDATE
Straighterline
Student Name:
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Lab Report Format Expectations
Utilize college level grammar and professional formatting when completing this worksheet.
Submissions without proper formatting, all required photos or sufficient responses will be
rejected.
Pre-lab Questions
1. Define the following terms.
a. hypertonic solution:
A hypertonic solution has more solutes outside the cell than inside. Water
moves out of the cell, causing it to shrink.
b. hypotonic solution:
A hypotonic solution has fewer solutes outside than inside the cell, so water
flows into the cell, possibly making it swell or burst.
c. isotonic solution:
An isotonic solution has an equal balance of solutes inside and outside the cell, so
water moves equally in both directions.
2. Define osmotic pressure.
Osmotic pressure is the force needed to stop water from moving across a membrane
due to differences in solute concentration.
3. Explain what would happen to a cell placed in a hypertonic solution.
The cell would lose water to its environment, leading it to shrink. In plants, this is
called plasmolysis, and in animal cells, it's called crenation.
EXPERIMENT 1: DIFFUSION THROUGH A LIQUID
Introduction Questions
1. State the molecular weight of the blue dye in grams
per mole. 800 g/mol
, 2. State the molecular weight of the red dye in grams
per mole. 322 g/mol
3. Why does this experiment require two dyes of different molecular weights? Answer this
question, ensuring you explain the purpose of these two dyes in relation to the
experiment.
Using dyes of different sizes helps show how molecular weight affects the rate of diffusion.
The smaller red dye moves faster than the larger blue dye.
Straighterline
Student Name:
Access Code:
Lab Report Format Expectations
Utilize college level grammar and professional formatting when completing this worksheet.
Submissions without proper formatting, all required photos or sufficient responses will be
rejected.
Pre-lab Questions
1. Define the following terms.
a. hypertonic solution:
A hypertonic solution has more solutes outside the cell than inside. Water
moves out of the cell, causing it to shrink.
b. hypotonic solution:
A hypotonic solution has fewer solutes outside than inside the cell, so water
flows into the cell, possibly making it swell or burst.
c. isotonic solution:
An isotonic solution has an equal balance of solutes inside and outside the cell, so
water moves equally in both directions.
2. Define osmotic pressure.
Osmotic pressure is the force needed to stop water from moving across a membrane
due to differences in solute concentration.
3. Explain what would happen to a cell placed in a hypertonic solution.
The cell would lose water to its environment, leading it to shrink. In plants, this is
called plasmolysis, and in animal cells, it's called crenation.
EXPERIMENT 1: DIFFUSION THROUGH A LIQUID
Introduction Questions
1. State the molecular weight of the blue dye in grams
per mole. 800 g/mol
, 2. State the molecular weight of the red dye in grams
per mole. 322 g/mol
3. Why does this experiment require two dyes of different molecular weights? Answer this
question, ensuring you explain the purpose of these two dyes in relation to the
experiment.
Using dyes of different sizes helps show how molecular weight affects the rate of diffusion.
The smaller red dye moves faster than the larger blue dye.
