1. What are two reason that some molecules require membrane proteins in order to help them across a membrane?

Describe pasteur’s results and how they disprove spontaneous generation.

Read the following scenario to answer the following question. in some zoos, rare crosses between a male lion and a female tiger have produced hybrid offspring called "ligers." male ligers are sterile but some female ligers are fertile. in the wild, lion and tiger ranges do not naturally overlap, making such a cross unlikely. furthermore, the solitary behavior of tigers and the social organizations of lions create behavioral differences. applying the biological species concept, the sterility of ligers reveals that a. lions are probably a subspecies of tigers b. tigers and lions are the same species c. a new species called "ligers" is forming d. tigers and lions are separate species

1. describe the structure and function of the specialized cells you observed in the video. 2. research the types of cells present in the kidney.