Nutrients Pollution
Surface Water Pollution
Oxygen Pollution
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:
Transcription & translation (Ans. A)
Explanation:
Prokaryotic organisms do not have membrane-bound organelles such as the nucleus, thus the process of transcription & translation occurs in the cytoplasm. Also because of the need for rapid life cycle, the mRNA molecules start to be made, & their ribosomes are ready to start making proteins more rapidly than Eukaryote, thus the process of the couple is quicker.
In eukaryotic organisms, transcription process start (happens) inside the nucleus of the cell and translation process can't start until the mRNA is transported out from the nucleus into the cytoplasm.
Answer:
Animal cells and plant cells
