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.
<span>Factors that can increase mutation rates are high and low temperatures, food additives, and UV rays. All of these answers are correct. Mutation rates in genes vary depending on many environmental effects. UV rays, along with varying temperatures, can cause mutations during cell division due to the damage they impart on the cells that are dividing. Dangerous food additives are believed to cause mutations, as seen in animal studies (ie. aspartame causing cancer in rats).</span>
Answer:
B) between the Persian Gulf and the Gulf of Oman
The statement is once the enzyme binds to the specific substrate molecule, structural changes can occur in the active site to accommodate the product.
Answer:
50%
Explanation:
Let's make a Punnett square to represent this, with X representing our dominant allele and x our recessive.
One homozygous dominant parent = XX
One heterozygous parent = Xx
X X
X XX XX
x Xx Xx
So two out of our four outcomes are heterozygous for the trait. That means the answer is <u>B. 50%.</u>
