AP Biology Chapter Guide
Chapter 8 Cell Signaling: Pages 131-146
Links to Prior Knowledge:
Hormone-receptor interactions are similar to the enzyme-substrate interactions described in
Chapter 3. Both rely on reversible conformational changes. Chapter 8 also introduces you to
some important groups of enzymes: kinases and phosphatases.
Cadherins, gap junction proteins, hormone receptors, and G proteins are just some of the many
membrane proteins mentioned in Chapter 8. Remember from Chapter 6 that the cell membrane is
dynamic—these proteins are always moving around, and their motion ensures that activated G
proteins interact with the enzymes they activate.
Learning Objectives: Students should be able to …
• Explain the functions of the extracellular material.
• Describe the different cell-cell connections in terms of their structure and function.
• Explain how intracellular signals integrate information.
• Describe the variations of cell signal processing in target cells.
Chapter 8 Vocabulary
primary cell wall tissues second messenger
pectins epithelia protein kinases
turgor pressure tight junction receptor tyrosine kinases (RTKs)
secondary cell wall desmosomes Ras
lignin selective adhesion phosphorylation cascade
extracellular matrix (ECM) antibody cross-talk
collagen cadherins quorum sensing
integrins plasmodesmata biofilms
fibronectins hormones
metastasis signal receptor
multicellularity signal transduction
G proteins
Test Yourself:
1. Predict whether molecules can pass between adjacent cells through middle lamella and tight
junctions and explain what would happen if cells in a frog embryo were treated with a molecule
that blocked a cadherin in muscle tissue.
2. Identify which characters in the scene correspond to the second messenger, G protein,
hormone, receptor, and enzyme activated by the G protein.
3. Explain how to set up dominos to stimulate a phosphorylation cascade, and why tipping the
first domino in the cascade simulates what happens when a receptor tyrosine kinase becomes
phosphorylated in response to hormone binding.
4. Compare the extracellular material for plants and animals.
5. Why are steroid receptors located inside of cells, while other hormone receptors are located on
the plasma membrane?
6. Compare and contrast a G-protein linked receptor and a tyrosine kinase receptor.