BIOLOGY
12th Edition
ISBN: 9781264839698
Author: Raven
Publisher: MCG CUSTOM
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Chapter 9, Problem 2S
The sheet of cells that form the gut epithelium folds into peaks called villi and valleys called crypts. The cells within the crypt region secrete a protein, Netrin-1, that becomes concentrated within the crypts. Netrin-1 is the ligand for a receptor protein that is found on the surface of all gut epithelial cells. Netrin-1 binding triggers a signal pathway that promotes cell growth. Gut epithelial cells undergo apoptosis (cell death) in the absence of Netrin-1 ligand binding.
a. How would you characterize the type of signaling (autocrine, paracrine, endocrine) found in this system?
b. Predict where the greatest amount of cell growth and cell death would occur in the epithelium.
c. The loss of the Netrin-1 receptor is associated with some types of colon cancer. Suggest an explanation for the link between this signaling pathway and tumor formation.
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Chapter 9 Solutions
BIOLOGY
Ch. 9.1 - Prob. 1LOCh. 9.1 - Prob. 2LOCh. 9.2 - Prob. 1LOCh. 9.3 - Prob. 1LOCh. 9.3 - Prob. 2LOCh. 9.4 - Prob. 1LOCh. 9.4 - Describe how information crosses the membrane in...Ch. 9.4 - Prob. 3LOCh. 9.4 - Prob. 4LOCh. 9.5 - Prob. 1LO
Ch. 9.5 - Prob. 2LOCh. 9 - Paracrine signaling is characterized by ligands...Ch. 9 - Signal transduction pathways a. are necessary for...Ch. 9 - The function of a ____is to add phosphates to...Ch. 9 - Which of the following receptor types is NOT a...Ch. 9 - How does the function of an intracellular receptor...Ch. 9 - Signaling through receptor tyrosine kinases often...Ch. 9 - Prob. 7UCh. 9 - Which of the following best describes the...Ch. 9 - Prob. 1ACh. 9 - The ion Ca2+ can act as a second messenger because...Ch. 9 - Different receptors can have the same effect on a...Ch. 9 - In comparing small G proteins like Ras and GPCR...Ch. 9 - Prob. 5ACh. 9 - The receptors for steroid hormones and peptide...Ch. 9 - Describe the common features found in all examples...Ch. 9 - The sheet of cells that form the gut epithelium...
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