Answer:
b. x chromosome inactivation
Explanation:
As you know, female cats have an x chromosome inherited from their mother and an x chromosome inherited from their father. After these two chromosomes are inherited and determine the sex of the cat, one of them will be disabled at some point in fetal development. Inside the X chromosome is the gene that determines the coat color of cats, when one of the two x chromosomes is deactivated, the other x chromosome will have all of its cells activated. In this case, if the activated chromosome is the one that has genes for the "cheetah" pattern of the coat color, all the descendants of this female cat also have the same coat.
Keeping constant the number of chromosomes of the species and perform a summary of recombination, through crossing-over
( Swapping – increases the <span>genetic variability )</span>
hope this helps!
Answer:
D. Sunlight
Explanation:
Since photosynthesis provides the energy the plant needs for growth, lack of light will stunt the plant's growth.
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.
A millipede has 750 legs! :)
