Vernier Software and Technology
Vernier Software & Technology

The Effect of Alcohol on Biological Membranes

Figure from experiment 8 from Biology with Vernier

Introduction

The primary objective of this experiment is to determine the stress that various alcohols have on biological membranes. Membranes within cells are composed mainly of lipids and proteins and often serve to help maintain order within a cell by containing cellular materials. Different membranes have a variety of specific functions.

One type of membrane-bound vacuole found in plant cells, the tonoplast, is quite large and usually contains water. In beet plants, this membrane-bound vacuole also contains a water-soluble red pigment, betacyanin, that gives the beet its characteristic color. Since the pigment is water soluble and not lipid soluble, it remains in the vacuole when the cells are healthy. If the integrity of a membrane is disrupted, however, the contents of the vacuole will spill out into the surrounding environment. This usually means the cell is dead.

In this experiment, you will test the effect of three different alcohols (methanol, ethanol, and 1-propanol) on membranes. Ethanol is found in alcoholic beverages. Methanol, sometimes referred to as wood alcohol, can cause blindness and death. Propanol is fatal if consumed. One possible reason why they are so dangerous to living organisms is that they might damage cellular membranes. Methanol, ethanol, and 1-propanol are very similar alcohols, differing by the number of carbon and hydrogen atoms within the molecule. Methanol, CH3OH, is the smallest, ethanol, CH3CH2OH, is intermediate in size, and 1-propanol, CH3CH2CH2OH, is the largest of the three molecules.

Objectives

In this experiment, you will

  • Use a Colorimeter to measure the color intensity of beet pigment in alcohol solutions.
  • Test the effect of three different alcohols on membranes.
  • Test the effect of different alcohol concentrations on membranes.

Sensors and Equipment

This experiment features the following Vernier sensors and equipment.

Additional Requirements

You may also need an interface and software for data collection. What do I need for data collection?

Standards Correlations

See all standards correlations for Biology with Vernier »

Experiment 8 from Biology with Vernier Lab Book

<em>Biology with Vernier</em> book cover

Included in the Lab Book

Vernier lab books include word-processing files of the student instructions, essential teacher information, suggested answers, sample data and graphs, and more.

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