The answer should be both
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.
Genetic Diversity in Plants. Genetic diversity is of fundamental importance in the continuity of a species as it provides the necessary adaptation to the prevailing biotic and abiotic environmental conditions, and enables change in the genetic composition to cope with changes in the environment
Answer:
Some species are similar in structure because they are evolved from the same ancestors while some differences are also present in them due to the changes occurs in the body because of adaptation to environmental conditions.
Grizzly bears and sea otters have canine teeth because canine teeth are used to crushing hard food materials such as fishes and shells.
Explanation:
Canine teeth are present in the grizzly bear and sea otters due to eating of food materials which are hard. Canine teeth used to crush the food materials.
An intron is a non-coding region of DNA. During alternative splicing, introns are removed.
- During eukaryotic transcription, a fragment of DNA (e.g., a gene) is used as a template to synthesize a complementary RNA sequence, usually a precursor mRNA (pre-mRNA).
- Subsequently, this pre-mRNA is processed by a mechanism called alternative splicing in order to produce a mature mRNA which is then used as template to synthesize a protein by a process called translation.
- During alternative splicing, non-coding regions of a gene called 'introns' are removed, where coding regions called 'exons' are spliced back together.
- If a cell transcribed and translated a gene’s intron by mistake, then additional amino acids would be inserted into the protein and therefore the resulting protein will be longer than normal.
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