BIOLOGY
5th Edition
ISBN: 9781265202859
Author: BROOKER
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Chapter 9, Problem 6TY
The relay protein Ras is part of the EGF pathway that promotes cell division (see Figure 9.10). The active form of Ras has GTP bound to it, whereas the inactive form has GDP. GTP is hydrolyzed to GDP and Pi to switch Ras from the active to the inactive form. Researchers have discovered that certain forms of cancer involve mutations in the gene that encodes the Ras protein. Which of the following types of mutations would you expect to promote cell division and thereby lead to cancer?
- a. a mutation that prevents the synthesis of Ras
- b. a mutation that causes Ras to bind GDP more tightly
- c. a mutation that prevents the GTP bound to Ras from being hydrolyzed
- d. a mutation that prevents Ras from binding to Raf
- e. both b and c
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We have studied Ras signal transduction pathway. In an experiment, two different mutations were produced using different chemicals. The proteins with mutation are listed below. State what will be the effect of each mutation and explain whether it will result in cell proliferation or not.
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Aberrant signaling through the Ras-BRaf-MAPK signal transduction pathway drives many cancers. This makes the pathway an attractive drug target, and many small molecules have been developed that target either Ras, BRaf or MAPK.
In malignant melanoma, one mutation in particular, where valine 600 of Braf is mutated to a glutamic acid (V600E), is found in the majority of cases. This mutation makes BRaf activation independent of upstream Ras activity.
Would a small molecule that targets Ras be effective in a melanoma case driven by Braf V600E? Explain your answer.
Describe the common signal transduction event that is perturbed by cancer-promoting mutations in the genes encoding RAS and NF-1. Why are mutations in RAS more commonly found in cancers than mutations in NF-1?
Chapter 9 Solutions
BIOLOGY
Ch. 9.1 - Figure 9.1 Response of a yeast cell to glucose....Ch. 9.1 - Prob. 1CSCh. 9.1 - Which type of signal, paracrine or endocrine, is...Ch. 9.1 - Prob. 3CCCh. 9.2 - Prob. 1CSCh. 9.2 - Prob. 2CSCh. 9.2 - Prob. 1CCCh. 9.3 - Prob. 1CSCh. 9.3 - Prob. 1CCCh. 9.3 - Prob. 2CC
Ch. 9.3 - In the case of signaling pathways involving...Ch. 9.5 - Prob. 1EQCh. 9.5 - Prob. 2EQCh. 9.5 - Prob. 3EQCh. 9.5 - Prob. 1CCCh. 9 - Prob. 1TYCh. 9 - Prob. 2TYCh. 9 - Prob. 3TYCh. 9 - Prob. 4TYCh. 9 - Prob. 5TYCh. 9 - The relay protein Ras is part of the EGF pathway...Ch. 9 - Prob. 7TYCh. 9 - Prob. 8TYCh. 9 - Prob. 9TYCh. 9 - Prob. 10TYCh. 9 - Prob. 1CQCh. 9 - Conceptual Questions What are the three stages of...Ch. 9 - Prob. 3CQCh. 9 - Prob. 1COQCh. 9 - Prob. 2COQ
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