Ecologist have proposed following explanation to lead maximize biodiversity at tropic.

A. Higher productivity in the tropics allows for more species present

 B. Old communities have greater species than younger community

 C. Natural enemies such as predators and parasite limit competition in the tropics, which allows more species to coexist

D. Very less intensity of disturbances in the tropics promote high succession diversity

#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:

#Question id: 2431

#Unit 2. Cellular Organization

Examples of actin cross-linking proteins include

a. fimbrin.        b. dystrophin.  c. α-actinin.     d. spectrin.      e. myosin S1.