The Galapagos finches were an important clue to Darwin's thinking about the origin of species. These finches are believed to have descended from a single ancestral species that colonized the Galapagos archipelago, America, over a short period of time. The Galapagos finches differ in their beak shape and size. Different species feed on seeds that vary in size and hardness. Which of the following is the most likely explanation for these patterns?

#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.

#Question id: 2427

#Unit 2. Cellular Organization

Known functions of actin-binding proteins include

a. severing of long filaments to generate shorter filaments.

b. inhibition of filament polymerization.                   

c. bundling of filaments.

d. acceleration of filament polymerization rates.

e. capping of the (+) end.

#Question id: 2428

#Unit 2. Cellular Organization

Which of the following prevent(s) acting disassembly?

a. cytochalasin D         b. jasplakinolide          c. latrunculin               d. phalloidin

#Question id: 2429

#Unit 2. Cellular Organization

Which of the following statements is (are) true of actin assembly?

a. ADP-actin can assemble into filaments.    

b. Actin (+) ends grow faster than actin (-) ends.

c. ATP-actin can assemble into filaments.

d. Toxins that alter the assembly of actin filaments have been used as tools to study actin in living cells.

#Question id: 2430

#Unit 2. Cellular Organization

Actin-binding proteins that generate actin filament bundles: