Answer:
(C) Aminoacyl-tRNA synthetases have an additional active site that binds to non-cognate tRNAs. The tRNAs that bind to this second active are hydrolyzed and released from the enzyme.
Explanation:
In case of translation, proof reading is done by aminoacyl-tRNA synthetases only. Aminoacyl-tRNA synthetases have two mechanisms to avoid error during translation which are mentioned as under:
<u>(1) Chemical proof reading:</u> Incorrect amino acids rather than being hydrolyzed in catalytic pocket get hydrolyzed in editing pocket and thus they hardly get attached to tRNA.
For example: For distinguishing similar amino acids like isoleucine and valine, isoleucyl-tRNA synthetase uses a second active site which is meant for only valine not for isoleucine. In this particular site, valine which had entered the enzyme is cleaved away with the help of editing reaction after which the enzyme is well prepared to process isoleucine which is the correct amino acid for this enzyme.
<u>(2) Kinetic proof reading: </u>Even if an incorrect amino acid has entered a particular aminoacyl-tRNA synthetase, it does not cause appropriate conformational change in the enzyme because of which the incorrect amino acid loosens from the enzyme and does not get incorporated.
Note: In this example, only chemical proof reading is mentioned not kinetic proof reading.
Answer:
A single gene form different isoforms of protein that result from the alternative splicing of pre-mRNA sequences. one gene many polypeptide hypothesis applies here very well. This whole process helps in proliferating informational diversity and functional capacity of a gene that'll ultimately he;p in gene regulation.
This alternative splicing of pre-mRNA also produces proteomic diversity that result in various development states as well as various disease conditions later.
A ecosystem productivity is a rate of generation of biomass.’’I know this because it states.”In economy productivity refers to the rate of generation of biomass in an economy.This shows that the economy its usually expressed in units of mass per unit.
