1. Consider a plant 20 cm tall growing in well watered soil. Ina dark and humid greenhouse, in the middle of the night, you measure the turgor pressure of aliving leaf cell of this plant using  a probe inserted in the cell. You find that the turgor pressureis 1.9 MPa. […]

A geneticist from an alien planet that prohibits genetic research escaped to Earth and brought with him two true-breeding lines of frogs. One frog line croaks by uttering “rib-it, rib-it” and has purple eyes. The other frog line croaks by muttering “knee-deep, knee-deep” and has green eyes. He mated the […]

a) A human nerve cell with an average surface area of 250,000micrometers squared has an extracellular potassium ion concentration of 3mM and an intracellular potassium concentration of 90mM. An impulse causes the potassium channels to open and the ions start to flow out of the cell. At what rate do […]

A box of 350N weight is at rest at the bottom of the plank thatis 6.0m long and rises 30 degree above the ground. Then the box is pushed up an inclined plank. If the incline is frictionless, and the pushing force is 600 to do the job, what is […]