Biology 160
NAME: _______________________________________
Reading Guide 05: The Process of Science and the Work of Membranes
This is DUE: ___________________
Come prepared to share your findings with your group.
Now that we’ve gone through one cycle of learning information in order to generate a model to explain a
biological phenomenon (in this case “Are we really what we eat?” - the flow of matter from food to our cells),
we hopefully have a better understanding of the process of science and the uncertainty involved. In this reading
guide we’ll dive into our next unit in order to model how cells get energy from food (now that it’s available to
them!) and look a little more closely at the process of science.
What you’ll learn in this reading guide:
 A formal definition of the processes of science
 The structure of cell membranes (phospholipid bilayer with integral membrane proteins)
 The different ways that molecules are transported across cell membranes
Reading:  Essential Biology, 4th or 5th Ed. (Simon, et al)
Ch 1 (p. 14-18; Process of Science) and Ch 5 (p. 83-87; Membrane Function)
 Lab 03: Osmosis and Diffusion
Chapter 1 p.14-18 and Lab 03:
1. What is a definition of science?
2. Explain the two main scientific approaches.
3. What is a “controlled experiment?”
4. What are “two key features that distinguish [science] from other styles of inquiry?”
5. What is their definition of a “fact?” (p.18)
6. Contrast the scientific definition of “theory” with the everyday definition of “theory” (p.18).
7. What does a “scientific argument” rely on? (see Lab 03: Diffusion and Osmosis)
Chapter 5 and Lab 03:
While reading constantly ask yourself, “How is this information helping me to understand how cells get
energy?”
1. To all the words/phrases in the text that are in BOLD: Highlight in your text or rewrite them or organize
them in some way (like flash cards or a table) to help you to learn and understand them.
2. Look up and write down the definitions of “solute,” “solvent,” and “solution” in the glossary. What is the
major solvent in a cell?
3. Draw a picture of a membrane protein embedded in a phospholipid bilayer membrane and list, with a short
description, the primary functions of membrane proteins:
4. What type of protein regulates the ability of food molecules to enter the cell?
5. What is the “simple rule of diffusion” and give an example of diffusion:
6. Define “concentration gradient.”
7. What is a “selectively permeable membrane” and give some examples of solutes that can pass freely through
a phospholipid bilayer membrane and some that cannot.
8. Compare and contrast “facilitated diffusion” and “active transport.” Feel free to draw diagrams as well as
describe with words.
Compare
Contrast
9. Redraw Figure 5.14 and add in labels for the “selectively permeable membrane;” which solution on both the
inside and the outside of the cell is isotonic, hypertonic, and hypotonic; and label which picture shows
plasmolysis.
10. Explain why the plant cell and the animal cell act differently in this figure (Figure 5.14) and which type of
osmotic environment (isotonic, hypertonic, or hypotonic) is the healthiest for each cell type.