BIS 152 Homework 3

BIS 152 Homework 3 - Shivali Gupta September 22, 2009 BIS...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Shivali Gupta September 22, 2009 BIS 152 Section 001 Maria Pallavicini T.A. Heather Bryan Homework 3 Chapter 5: #1, 3, and 4 Chapter 6: #3, and 5 1. Why is autocrine signaling an intrinsically destabilizing force for a normal tissue? Autocrine signaling is an intrinsically destabilizing force for a normal tissue, since normal cells do not synthesize and release a growth factor ligand whose associated receptor they express on the cell surface they have a controlled cell proliferation. Cell proliferation is controlled in normal cells because in order for them to proliferate they must receive appropriate growth factors from the neighboring cells. However, in many types of cancer, tumor cells acquire the ability to express a growth factor that is not normally expressed by cells of their lineage, whose associated receptor is expressed on the surface of the cell. This results in an autocrine signaling loop which continually expresses growth factors that results in constitutive uncontrolled cell proliferation. 3. The responsiveness of a cell to exposure to a growth factor are usually attenuated after a period of time (e.g. half an hour), after which time it loses this responsiveness. Given what you have already learned about growth factor receptors, what mechanisms might by employed by a cell to reduce its responsiveness to a growth factor? Given the information presented in the text, one of the many mechanism that can be employed by a cell to reduce its responsiveness to a growth factor is that a cell can avoid any further transphosphorylation of the tyrosine kinases or the serine and threonine kinases, since the transphosphorylation of these kinases
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 06/23/2010 for the course BIO Bioap taught by Professor Ling during the Spring '10 term at UCM.

Page1 / 3

BIS 152 Homework 3 - Shivali Gupta September 22, 2009 BIS...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online