The figure below illustrates A) normal development of a sea urchin embryo, B) development of the isolated animal hemisphere and C) development of the animal hemisphere + micromeres. Note that sea urchins are triploblasts and form all three germ layers (blue = ectoderm, yellow = endoderm, red = mesoderm). While the animal half of an early sea urchin embryo does not gastrulate, and does not form a normal larva when isolated, the micromeres can rescue gastrulation and development of the animal half; the resulting larva does have mesoderm, but is lacking endoderm. See the picture below. You find that the Delta protein is expressed in the micromeres of an intact sea urchin embryo.  You know that Delta is a signaling molecule that activates the Notch receptor on adjacent cells and you hypothesize that Delta from the micromeres is interacting with Notch on the veg2 cells to specify the secondary mesodermal (from veg2) fate.  B) Describe a ‘loose it’ experiment that would show that the interaction of Delta and Notch on adjacent cells is necessary for the rescuing ability of the micromeres.  Note that you cannot make genetic mutants in sea urchins, so don’t propose that!  Include a result that would be consistent with your hypothesis and one that is inconsistent with your hypothesis.     

1. The nurse is teaching about the process of exchanging gases through the alveolar capillary membrane. Which term will the nurse use to describe this process?

Analogous or homologous?  Whales evolved from a land mammal that found its way back to the sea and adapted to life underwater.  Thus, whales have lungs and breathe air from the surface like mammals, rather than gills that extract oxygen from the water like fish.  Given this information are the following comparisons examples of analogy or homology?   A) Whale fin and dog front leg (at the level of ‘forelimbs’) B) Whale fin and zebrafish fin (at the level of ‘fin’)

4. The patient is experiencing angina pectoris. Which assessment finding does the nurse expect when conducting a history and physical examination?

16. Which intervention is appropriate to include in the plan of care for a patient experiencing narcolepsy?

A 0.100 M solution of a weak monoprotic acid, HA, has a measured pH of 2.87 at 25 °C. What is the best estimate of Ka for HA?

A student titrates 25.00 mL of 0.100 M acetic acid (Kₐ = 1.8 × 10⁻⁵) with 0.100 M NaOH at 25 °C. What is the best estimate of the pH at the equivalence point? (Use Kw = 1.0 × 10⁻¹⁴.)

A student mixes 50.0 mL of 0.100 M HCl with 30.0 mL of 0.100 M NaOH. What is the pH of the resulting solution? Assume volumes add.

A student mixes 25.00 mL of 0.100 M NH₃ with 20.00 mL of 0.100 M HCl. Which pair of solute species is present in the greatest amounts after the reaction goes to completion?

A 2.50 × 10⁻³ M Ba(OH)₂ solution is prepared at 25 °C. Assuming complete dissociation, what is the pH of the solution?