Which of the following crosses lipid bilayers the slowest?
A) a sodium ion
B) a small, polar molecule like water
C) a large, polar molecule like glucose
D) a small, nonpolar molecule like oxygen (O2)
Answer: A
You might also like to view...
Which of the following is not a function associated with the cytoskeleton?
A) scaffold for support and maintenance of cell shape B) anchoring site for mRNA during transcription C) cell division D) organizes the organelles within the cytoplasm E) signal transducer
As a naturalist, you are responsible for training volunteers in the identification of the types of amphibians. The volunteers will use this information to correctly describe the animals to school groups that will visit your nature center. The training documentation for the volunteers lists important characteristics of the different groups of amphibian, but you notice that one of the items on the list is incorrect. Indicate which description is not correct.
A. Frogs and toads have external fertilization whereas salamanders and caecilians have internal fertilization. B. Frogs, toads, and most salamanders have four legs whereas caecilians are legless. C. Frogs and toads lay eggs whereas some caecilians lay eggs and others give birth to live young. D. Salamanders and caecilians have external tails whereas frogs and toads do not. E. Adult frogs, toads, and salamanders are predators of insects and other small animals whereas caecilians are herbivores.
Although Watson and Crick are credited with the discovery of the structure of DNA, they based this discovery on the
bench work of many other scientists of the time. Name at least three different pieces of knowledge that Watson and Crick used in their discovery that was based on work from other scientists.
What will be an ideal response?Urea is a small molecule that is transported out of most cells by passive diffusion, but some cells, including kidney cells, have urea-facilitated transporters
Given an assay to measure the amount of urea on one side of the cell plasma, design an experiment to distinguish which mechanism an uncharacterized cell you have isolated uses to transport urea. Include graphs, if this aids in your discussion. What will be an ideal response?