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.
Lamprey and hagfish are jawless fish, with skeletons composed of cartilage. They do not have scales and are considered primitive fish. They are in the superclass cyclosystoma.
This definition above refers to the geographic isolation.
It means exactly what it says in the definition - one species is left behind from the rest of the population, and it stays in that particular location, evolving and changing from the species and population it was once a part of.
Answer:
1/2 x 9000 x 30x30=4050000 joule
Explanation:
4050000 energy
The greatest degree of genetic variation would be found in an offspring resulting from sexual reproduction.
<u>Explanation:</u>
Asexual reproduction produces very less variations. Asexual reproduction requires only one parent and thus the offspring would be very similar to the parent. The chance of variations in offspring is very less.
But the case of sexual reproduction is different. Sexual reproduction involved two parents and each parent contribute equal amount of genetic material to the progeny.
Some characters of the offspring will be like one or the other parent and some characters will be a combination of the characters of both parents
. Such a combination produces variant offspring.
