Dog breeders maintain the purity of breeds by keeping dogs of different breeds apart when they are fertile. This kind of isolation is most similar to which of the following reproductive isolating mechanisms?

#Question id: 2421

#Unit 2. Cellular Organization

Listeria is a bacterial parasite that has evolved unique ways to enter animal cells and then use actin polymerization for its intracellular movement.  Which of the following statements is true in regard to Listeria and actin polymerization?

#Question id: 2422

#Unit 2. Cellular Organization

 What actin-binding protein mediates gel-sol transitions?

#Question id: 2423

#Unit 2. Cellular Organization

What is the function of thymosin beta-4?

#Question id: 2424

#Unit 2. Cellular Organization

Which of the following statements correctly describe(s) actin?

a. Actin is a highly conserved protein.

b. Multiple actin genes may be found in higher eukaryotes.

c. Actin is the most abundant protein in a eukaryotic cell.

d. Individual actin filaments can be observed by electron microscopy.

e. One end of an actin filament is different from the other. 

#Question id: 2425

#Unit 2. Cellular Organization

Which of the following is (are) actin-based structures?

a. adherins belt                        b. contractile ring        c. mitotic spindle

d. nuclear lamina         e. stress fibers

#Question id: 2426

#Unit 2. Cellular Organization

Actin assembly in vitro

a. consists of three phases.     

b. requires addition of actin oligomers termed nuclei.

c. requires ATP hydrolysis.

d. is reversible.

e. requires actin-binding proteins.