Answer: C). prolong the effect of epinephrine by maintaining elevated cAMP levels in the cytoplasm
Explanation: In the epinephrine pathway, binding of epinephrine to its receptor triggers a conformational change in the receptor and the interaction of the receptor with its associated Gs protein. This interaction causes the replacement of GDP bound to Gs protein with GTP thus activating the Gs protein. The activation of the Gs protein causes the alpha subunit of the Gs protein to dissociate and move to adenylyl cyclase, another membrane protein in the pathway. The association of the alpha subunit of the Gs protein with adenylyl cyclase activates adenylyl cyclase which in turn catalyzes the synthesis of cyclic AMP (cAMP) a second messenger. cAMP is quickly degraded to 5'-AMP by an enzyme phosphodiesterase. Inhibition of the activity of phosphodiesterase will increase the half life and the cytoplasmic level of cAMP thus potentiating the action of epinephrine.
Answer:
C) The smaller population will be more affected than will the larger population, because the smaller population has less genetic variation than the larger population has.
Explanation:
Genetic variations are present in the natural populations. Some of the genetic traits become adaptive under the changed environmental conditions and allow the individuals carrying them to survive and reproduce. In this way, the genetic variations help to maintain a population.
Therefore, a larger population of a squirrel species with more genetic variations will have less intense impacts of a disturbance/natural calamity and/disease. On the other hand, a smaller population of the same species with a lesser number of squirrels has fewer genetic variations. This population is more likely to be affected in a negative way by a disturbance such as pathogen.
