A first messenger molecule activates a receptor that stimulates Enzyme A, which synthesizes 100 second messenger molecules. In turn, each second messenger activates only one molecule of Enzyme B, which once activated, phosphorylates 100 molecules of Enzyme C that each phosphorylate 80 molecules of Enzyme D. In the last step, each Enzyme D phosphorylates 50 transcription factors. How many transcription factors are phosphorylated in response to the first messenger binding to the receptor? How many transcription factors would be phosphorylated if one copy of the Enzyme D gene were inactivated (heterozygous genotype) so that there were only half the number of functional Enzyme D molecules in the cell? Explain.

The last few miles of the marathon are the most difficult for heather, her hair plastered to her head, sweat clinging to her arms, and her legs already feeling as if they had nothing left, just dead weight. after grabbing a cup of ice water, she feels the ice cubes smash against her nose as she gulps some cool refreshment and keeps on running. in these last few miles, the breeze kicks up and she finally feels some coolness against her skin. drips of sweat, once clinging to her forehead, now spill down, and heather feels more pain as the sweat flows into her eyes.which of the following is the most likely reason why the ice struck heather’s nose when she took a drink? a) water can function as a solvent. b) water can store large amounts of heat. c) water can moderate temperatures through evaporative cooling. d) the density of water decreases when it freezes. e) water has a cohesive nature.sweat remained on heather’s forehead and arms because of the a) high salt content of sweat b) cohesive nature of water c) ability of water to moderate heat d) high evaporative cooling effect of water e) ability of water to act as a solvent