IAG_9.docx IAG_9.docx IAG_9.docx
OpenStax Biology 2e Instructor Answer Guide
Biology 2e
Unit 2: The Cell
Chapter 9: Cell Communication
Visual Connection Questions
1. HER2 is a receptor tyrosine kinase. In 30 percent of human breast cancers, HER2 is
permanently activated, resulting in unregulated cell division. Lapatinib, a drug used to treat
breast cancer, inhibits HER2 receptor tyrosine kinase autophosphorylation (the process by
which the receptor adds phosphates onto itself), thus reducing tumor growth by 50 percent.
Besides autophosphorylation, which of the following steps would be inhibited by Lapatinib?
c. The downstream cellular response would be inhibited.
IAG_9.docx IAG_9.docx IAG_9.docx
, IAG_9.docx IAG_9.docx IAG_9.docx
OpenStax Biology 2e Instructor Answer Guide
2. In certain cancers, the GTPase activity of the RAS G-protein is inhibited. This means that the
RAS protein can no longer hydrolyze GTP into GDP. What effect would this have on
downstream cellular events?
ERK would become permanently activated, resulting in cell proliferation, migration, adhesion,
and the growth of new blood vessels. Apoptosis would be inhibited.
IAG_9.docx IAG_9.docx IAG_9.docx
OpenStax Biology 2e Instructor Answer Guide
Biology 2e
Unit 2: The Cell
Chapter 9: Cell Communication
Visual Connection Questions
1. HER2 is a receptor tyrosine kinase. In 30 percent of human breast cancers, HER2 is
permanently activated, resulting in unregulated cell division. Lapatinib, a drug used to treat
breast cancer, inhibits HER2 receptor tyrosine kinase autophosphorylation (the process by
which the receptor adds phosphates onto itself), thus reducing tumor growth by 50 percent.
Besides autophosphorylation, which of the following steps would be inhibited by Lapatinib?
c. The downstream cellular response would be inhibited.
IAG_9.docx IAG_9.docx IAG_9.docx
, IAG_9.docx IAG_9.docx IAG_9.docx
OpenStax Biology 2e Instructor Answer Guide
2. In certain cancers, the GTPase activity of the RAS G-protein is inhibited. This means that the
RAS protein can no longer hydrolyze GTP into GDP. What effect would this have on
downstream cellular events?
ERK would become permanently activated, resulting in cell proliferation, migration, adhesion,
and the growth of new blood vessels. Apoptosis would be inhibited.
IAG_9.docx IAG_9.docx IAG_9.docx
