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: Electromagnetism
Explanation: Electromagnetism is one of the four fundamental forces (the other three are gravity, strong nuclear force and weak nuclear force.) It acts between all the particles having an electrical charge.
Answer:
Maybe 2,3 points
Explanation:
1. receive stimuli messages from inside and outside the body..
2. responding to stimuli by sending messages throughout the body.
Hemostasis is the process by which bleeding is stopped, that is, a process by which the blood is kept back in the broken blood vessel. It is the first stage in the wound healing process.
During hemostasis, three rapid steps occur simultaneously. In the first step, the blood vessel constrict in order to reduce the quantity of blood that is flowing out, secondly, platelets stick together in order to form a temporary seal which covers the break and thirdly blood clottings formed by adding fibrin threads which serves as molecular glue on the surface of the wound.
