The Cell Membrane and Diffusion. Activity 8: The Cell Membrane and Diffusion LIMITED LICENSE TO...

Activity 8

The Cell Membrane and Diffusion

Activity 8: The Cell Membrane and Diffusion

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Get Started

What can you conclude about the permeability of the balloon from the demonstration?

What is your evidence?


Introduction

Diffusion occurs when a substance moves from a solution with a high concentration of the substance to a solution with a low concentration of the substance.

Read the introduction.

Activity 8: The Cell Membrane and DiffusionActivity 8: The Cell Membrane and Diffusion

What factors determine whether a substance moves across a model of the cell membrane?

Challenge


Procedure

What changes did you observe in the model cells in solutions of lower, equal, and higher sugar concentrations?

How would you explain what is happening in these model cells?

Part A: Investigating Water and Sucrose Solutions


Procedure

Read Procedure step 12 carefully. The numbers of atoms in the formulas give a general idea of the size of the molecule.

Part B: Membranes and the Movement of Molecules


Procedure

Discuss with your partner the main ideas of the reading and the comments you made on the sticky notes.


In Part A, what changes did you observe in the model cell when the external environment surrounding the model cell contained each of the following:◦A. a less concentrated solution than the cell’s contents.

Explain.◦A. a more concentrated solution than the cell’s contents.

Explain.◦A. equally as concentrated as the cell’s contents.

Explain.

Analysis 1


Analysis 1


Follow Up

In Part B, which substances passed through the model membrane? Explain why. Support your explanation with evidence from the laboratory.

Analysis 2


Follow Up

Based on the HIV/AIDS case study, what are the advantages and trade-offs of working to develop an HIV/AIDS vaccine, as opposed to focusing on education?

Analysis 6


Follow Up

Describe the evidence and your conclusions about which substances could cross the model membrane used in this activity. Use the terms diffuse and diffusion in your response.


What factors determine whether a substance moves across a model of the cell membrane?

Revisit the Challenge


Key Vocabulary

cell membrane, membrane control diffuse, diffusion HIV/AIDS hypothesis osmosis phospholipid (lipid) bilayer

Key Vocabulary

The Cell Membrane and Diffusion. Activity 8: The Cell Membrane and Diffusion LIMITED LICENSE TO...

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