Cell Membrane and Dialysis Experiment

Mr. Cahill guides seventh-graders through Investigation 5.3, focusing on how food moves into cells. The lesson covers the cell membrane, cytoplasm, and the environment using a model with dialysis tubing. Students learn about semipermeable membranes and conduct six trials to observe the movement of glucose, starch, and water through the membrane. The experiment aims to demonstrate the selective permeability of cell membranes and reinforce concepts from the life science unit.

What is the main focus of Investigation 5.3?

• How cells communicate

• How cells produce energy

• How food moves into cells

• How cells divide

What does the dialysis tubing represent in the cell model?

• The cell wall

• The cell nucleus

• The cytoplasm

• The cell membrane

What characteristic of the dialysis tubing allows it to model the cell membrane?

• It is flexible

• It is impermeable

• It is semipermeable

• It is transparent

Which materials are used to model the contents of the cytoplasm?

• DNA, RNA, and proteins

• Salts, minerals, and vitamins

• Proteins, lipids, and carbohydrates

• Glucose, starch, and distilled water

What is the purpose of the external environment model in this investigation?

• To illustrate the movement of substances between capillaries and cells

• To explain how cells communicate

• To demonstrate cell division

• To show how cells produce energy

What is the main goal of the experimental trials?

• To observe cell division

• To analyze the chemical composition of cells

• To test the movement of substances through the cell membrane

• To measure the size of molecules

In the first trial, what is placed inside the dialysis tubing?

• Starch

• Distilled water

• Salt solution

• Glucose

What is the environment outside the dialysis tubing in the first trial?

• Salt solution

• Starch solution

• Distilled water

• Glucose solution

How many different trials are set up in the experiment?

• Seven

• Four

• Five

• Six

What is being tested in the trials regarding the cell membrane?

• The strength of the membrane

• The color of the membrane

• The permeability of the membrane to different substances

• The temperature of the membrane