4. What is a biodiversity hot spot?

3. Given the latitudinal differences in sunlight intensity, how might you expect the carrying capacity of plant species found at the equator to compare with that of plant species found at high latitudes?

2. Please describe what is an action potential, including depolarization, hyperpolarization, and repolarization. Please indicate the major ion driving the change in membrane potential in each phase.

40. Which of the following statement about myelination is incorrect? (A) Myelination is required in both the CNS (central nervous system) and PNS (peripheral nervous system). (B) Myelination involves the ensheathment and insulation of axons by radial glial cell membranes. (C) Myelinating Schwann cells extend their processes to wrap up axons at a 1:1 relationship. (D) Myelinating Oligodendrocytes extend multiple processes that will contact and myelinate several axons. (E) None of above is incorrect.

39. The term "synapse" has been used to describe the contact points between: (1) neuronal cells. (2) immune cells. (3) epithelial cells. (A) (1) (B) (2) (C) (3) (D) None of above (E) All of the above

38. Control of gene expression by Ca2+ can occur through which of the following mechanism? (1) Changes in the transactivating properties of transcription factors following the activation of Ca2+-dependent kinases. (2) Changes in the transactivating properties of transcription factors following the activation of Ca2+-dependent phosphatases. (3) Translocation of the C-terminal fragment of an L-type Ca2+ channel to the nucleus where it binds to a nuclear transcription factor. (A) (1) (B) (2) (C) (3) (D) All of above are correct (E) None of above is correct