You do an experiment in which you increase the concentration of phosphate in a solution and measure the uptake by plant cells. You find that once the concentration of phosphate reaches 1 gram per liter adding more phosphate does not increase uptake any further. From this you would conclude that phosphate is taken up by ________.
A. endocytosis.
B. osmosis.
C. exocytosis.
D. facilitated diffusion.
E. active transport.
Answer: D
You might also like to view...
Which statement is false about intact neurons?
a. An action potential can be generated in an input zone only. b. A trigger zone has enough sodium gates to initiate an action potential. c. Each portion of a membrane has its own recovery time. d. The potassium gates open during the recovery period. e. Gated sodium channels are inactivated during the recovery period.
Ribosomes leave the nucleus as
a. intact 80S ribosomes. b. intact 70S ribosomes. c. 40S and 60S ribosomal subunits. d. 18S and 28S rRNAs.
Because water _______, it is ideal as the most abundant molecule in cells.
a. has low heat of vaporization b. is a polar molecule that can form hydrogen bonds with itself and with other polar molecules c. dissolves nonpolar molecules d. expands when it freezes
The first self-replicating molecule was probably ________
Fill in the blank(s) with correct word