A researcher studying bacterial toxin predicts that a lysine within the toxin is important for binding it’s target cell.  She used site-directed mutagenesis to change a codon for lysine (AAA) to one for asparagine (AAU).  However, the mutant toxin still binds to its target cell just as well as the wild-type toxin bound and appears to have no other changes. This type of mutation is probably

TLS Online TPP Program

#Question id: 8903

#Unit 9. Diversity of Life Forms

Terry detaches the snakelike organism from the fish and uses a knife to cut off its head. In doing so, its brain slides out onto the deck of the boat. Terry peers into the cut end of the head and notices that the brain had lain in a sort of pan-like structure that only partially surrounded the brain. What is the structure Terry is observing, and what is it made of?

TLS Online TPP Program

#Question id: 3977

#Unit 3. Fundamental Processes

Which one of the following statements about eukaryotic RNA polymerases is correct?

TLS Online TPP Program

#Question id: 27010

#Unit 10. Ecological Principles

Toxoplasmosis in humans is caused by Toxoplasma gondii, an obligate intracellular parasite with two different life cycles, sexual and asexual. The sexual cycle occurs in which ONE of the following definitive hosts?

TLS Online TPP Program

#Question id: 2342

#Unit 2. Cellular Organization

Which of the following is a requirement for osmosis to occur?

TLS Online TPP Program

#Question id: 26865

#Unit 10. Ecological Principles

Production efficiencies is greater in