Lesson 12 GRQ (BIOL 103)
Lesson 12 (Cell signaling)
CONCEPT 5.6
Start with “Reception, the Binding of a Signaling Molecule to a Receptor Protein”, knowing that
some of this will be review from the previous lesson.
1. True or false (explain): All G protein coupled receptors (GPCRs) stimulate cell division.
2. For what type of molecule would you expect to see an intracellular receptor? Why?
3. What is a transcription factor? Where in a cell do they function?
4. Is a signal transduction cascade always just passing the signal along at the same
amplitude (e.g., proportional to the amount of ligand relaying the signal)? What else can
happen?
5. What does a protein kinase do?
Watch the animation on Signal Transduction Pathways on Mastering Biology.
6. What is a phosphorylation cascade?
7. What is a protein phosphatase?
8. Walk yourself through figure 5.26, explaining the steps to yourself aloud. Then, explain
what is happening in this figure here in 3-4 sentences and in your own words.
9. What is the purpose of a second messenger? What are some examples of second
messengers from your book?
10. Walk yourself through figure 5.27, explaining the steps to yourself aloud. Then, explain
what is happening in this figure here in 3-4 sentences.
Lesson 12 GRQ (BIOL 103)
11. Answer the following questions about a signaling molecule and be sure to give a
justification for your answer.
1. Can a signaling molecule cause transcription of a gene?
2. Can a signaling molecule cause the modification of a protein that already
exists in the cell?
CONCEPT 16.3 **Some of this will also be review from previous lessons in unit 2**
12. Define the following terms in your own words.
Oncogene
Proto-oncogene
Tumor suppressor
13. Spend time reviewing figure 16.17 and summarize in your own words four different ways
in which a proto-oncogene can be mutated to become an oncogene.
1.
2.
3.
4.
14. What is Ras and how is it involved in the signal transduction of cell division?
15. Is Ras a proto-oncogene or a tumor suppressor protein. Explain.
16. How would an overactive Ras affect cell cycle division (faster/slower)? How would Ras
that is unable to be activated affect cell cycle division (faster/slower)?
17. What is p53 and how is it involved in the signal transduction of cell division?
18. Is p53 a proto-oncogene or a tumor suppressor protein. Explain.
Do not read “The multistep model of cancer development” and subsequent subsections of
CONCEPT 16.3
Lesson 12 GRQ (BIOL 103)
