At a Glance


  • Biology
  • Chemistry

Instructional Level

  • College & CEGEP


  • General Biology II

Tasks in Workflow

Social Plane(s)

  • Individual
  • Group
  • Whole Class

Type of Tasks

  • Collecting & seeking information
  • Discussing
  • Reviewing & assessing peers
  • Revising & improving
  • Presenting

Technical Details

Useful Technologies

  • myDALITE for the pre-class quiz

Class size

  • Small (20-49)


  • Single class period (< 90 mins)

Instructional Purpose

  • Preparation & knowledge activation
  • Application & knowledge building


The aim of the activity is to increase students’ understanding of molecules’ movement through the cell membrane while using their knowledge of molecules’ shape and polarity.

The cellular and physiological effects of molecules greatly depend on its absorption by the cells, students can apply this knowledge to understand the effect of many molecules, drugs, pathogens, vaccines, etc. Acting as either part of the membrane or as specific molecules wanting to cross the membrane, the class acts out membrane transport. As each molecule (student) passes through the membrane, other students provide immediate feedback on whether the process was correctly carried out. Afterwards, the class creates a summary table together or individually for homework.

This activity can be described as peer learning, while students have to use knowledge from various parts of the biology and chemistry courses, which some students may recall more than others. The activity can be done in many phases. The first phase described here can be done in 30-45 minutes, after a lesson on membrane transport.

Instructional Objectives

  • Students will be able to state the detailed composition of cell membranes and how it acts as a boundary
  • Students will be able to describe the various mechanisms for molecules to cross a cell membrane
  • Students will be able to identify the mechanism used by a specific molecule to cross a cell membrane depending on the molecule’s properties
  • Students will describe how the concentration of a molecule affects its transport (diffusion and osmosis, active and passive transport)

Workflow & Materials


Activity Workflow

View on CourseFlow

Contributor's Notes

  • Students visualize and reflect on how some molecules are able to cross the cell membrane based on their solubility while other molecules need a protein with the same solubility to help them cross
  • Students integrate the knowledge from chemistry and biology. It helps reduce the ‘silo’ learning and hopefully increases the contextualization of learning
  • Increases engagement
  • In a big class, students are often paired to act as one molecule, and it can be more difficult for the teacher to evaluate/address the understanding of individual students. One way to reduce this is by giving a short quiz prior to the activity (Moodle or other, but results visible by the teacher) so students can revisit the concepts and be aware of what they should review before class
  • In a small class, it may be hard to get the desks out of the way
  • Molecules chosen must represent a wide range of properties, that students can compare: large and small molecules with the same polarities, molecules of the same size with various polarities. Use molecules well known to students: water, glucose, alcohol etc.
  • The activity can be revisited in a second phase to exemplify cell signalling, where a molecule (adrenaline for eg.) is already in the cell. A cascade can then be shown where one molecule activates 2 second messengers, which then each activates another 2 etc.

Applied Strategies


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