Computer Interfacing

Teacher Information: The Effect of Alcohol on Biological Membranes

Answers to Questions

1. 1-Propanol damaged membranes more at low concentrations. At 20% alcohol, propanol caused over three times the pigment to be released into the solution compared to the other two alcohols.

2. 1-Propanol seems to affect membranes the most, as there is more pigment (cellular damage) at any concentration of alcohol.

3. 1-Propanol is most toxic. These data support that statement, as it causes maximal membrane and cellular damage.

4. Student answers may vary. In many experiments, the percentage of methanol that is most damaging is about 80%. For ethanol and 1-propanol, the most damaging concentration is approximately 60%.

5. Answers may vary.

Challenge Question

1. The larger the molecule, the greater the extent of membrane damage. 1-Propanol, a three carbon molecule, is larger than ethanol, a two carbon molecule and methanol, a one carbon molecule. Lipids can be composed of hydrocarbon chains, which are non-polar. As the alcohol increases in length, it becomes less polar than smaller alcohols, and are able to mix with lipids to a greater extent. Since the -OH branch of the alcohol mixes with water, the longer alcohols can mix with both lipids and water. This tends to disrupt the membrane much as detergents and soaps do. For this reason, larger alcohols might cause more extensive membrane damage.

Technology in Education Index

Let's Collaborate Index