Answer:
According to the previous observational study it is possible to notice that thinning determined in great way the rate of trees that survived the fire.
Explanation:
In general the trees that had been previously cut, were the ones that presented more resistance to the fire, while the trees that had not been thinned were the ones that were severely affected in the spreading conflagration. Reason why in comparison of these two samples, it would be possible to conclude that previously cutting down trees can survive better to the spreading fire.
The experiment conducted by Paul was not a waste of his time and resources even though he could not accomplish the experiment he initially prepared to conduct. The reluctance of the penguins to eat burgers even though they were starving and losing weight pointed towards the fact that they do not find junk food appealing. It could be concluded from their reluctance that they will eat only their normal diet rather than something they have never eaten before.
Answer:
For both actin and microtubule polymerization, nucleotide hydrolysis is important for decreasing the binding strength between subunits on filaments.
Explanation:
Cytoskeletal filaments are common to eucaryotic cells and are impotartant to the spatial organization of cells. Intermediate filaments provide mechanical strength and resistance to shear stress. Microtubules determine the positions of membrane-enclosed organelles and direct intracellular transport. Actin filaments determine the shape of the cell's surface and are necessary for whole-cell locomotion. A large number of accessory proteins are present that link the filaments to other cell components, as well as to each other. Accessory proteins are essential for the assembly of the cytoskeletal filaments in particular locations, and it includes the motor proteins that either move organelles along the filaments or move the filaments themselves.
Actin filaments and microtubules are assembled with expenditure of energy i.e the ATP/GTP tightly bound to actin/tubulin is irreversibly hydrolyzed to ADP/GTP during the assembly process, and liberation of Pi in the medium occurs subsequent to the incorporation of subunits in the polymer. Pi release acts as a switch, causing the destabilization of protein-protein interactions in the polymer, therefore regulating the dynamics of these fibres. The progress is made in four areas: the chemistry of the NTPase reaction; the structure of the intermediates in nucleotide hydrolysis and the nature of the conformational switch; the regulation of parameters involved in dynamic instability of microtubules; and the possible involvement of nucleotide hydrolysis in the macroscopic organization of these polymers in highly concentrated solutions, compared with the simple case of a equilibrium polymers.
