What is meant by signal amplification? Give two examples. What will be an ideal response?
Signal amplification occurs when a signaling molecule bound to a receptor produces changes in
millions of molecules in a cascade of reactions within the cell.. This observation explains how just a
few signal molecules, ie. neurotransmitters, ions or hormones molecules can lead to a major
response by a cell.
Epinephrine binding to a G- protein - receptor activates adenyl cyclase which catalyzes the production
of many cAMP molecules . Then each cAMP activates many protein kinases down the cascade of
reactions. .
The Ras/MAP kinase is stimulated by epidermal growth factor binding to tyrosine kinase receptor.
This binding leads to actvation of th G small protein. Ras then activates MAP-kinase signaling
pathway . A series of MAP kinases in the pathway are then activated by phosphorylation
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Which of the following life history traits of mice is NOT an advantage for its use as a model
organism?
a. Reproductive rate. b. Generation time. c. Small size. d. Maintenance in the laboratory. e. Large size.
The specific traits of a particular organism enabling it to survive, grow, and reproduce within a given environment are called
A) mutations. B) genes. C) adaptations. D) phenotypes.
Besides selection on multilocus genotypes, there are two other mechanisms that can create linkage disequilibrium. What are they?
What will be an ideal response?
If after several generations all males have 12-point antlers, this development will have been due to:
A) founder effect. B) stabilizing selection. C) disruptive selection. D) directional selection.