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:
Broca's area refers to a motor speech region, which assists in movements needed at the time of the production of speech. When an injury takes place in the frontal parts of the left hemisphere, it can give rise to various kinds of language issues. This section of the brain plays an essential role in putting words together to produce complete sentences. The injury to the left hemisphere is known as Broca's aphasia, also known as expressive aphasia.
Wernicke's aphasia also called receptive aphasia, posterior aphasia, or sensory aphasia is a kind of aphasia in which individual encounters with difficulty in understanding spoken and written language. Thus, the two kinds of aphasia are expressive aphasia in which one faces difficulty in conveying thoughts via writing and speech. The other is receptive aphasia, in which one finds difficulty in understanding the written or spoken language.
By analyzing the symptoms that whether the patient exhibits difficulty in understanding speech and using accurate words to express thoughts or the movements that are needed to generate speech, one can find the site of destruction.
Answer:
fg
Explanation:
white is recessive since 2 fs were needed to get white so if half the children are white then the second parent has to have the recessive gene f and since the other half kids are purple then they need the G gene which is purple and is the dominant gene
A cell membrane pump helps human cells to maintain a relatively constant sodium and potassium concentration.
<u>Option: A</u>
<u>Explanation:</u>
Sodium potassium pump is a plasma membrane protein that utilizes energy ATP — Triphosphate Adenosine turning into ADP — Adenosine Diphosphate to deliver intracellular and extracellular sodium (NA+) and potassium (K+) ions sequentially. The purpose of this entire mechanism is to preserve cell equilibrium.
The extracellular medium has a greater concentration of Na while the K concentration of the intracellular fluid is lower. Proteins trap sodium ions in the cytoplasm and pump them out from the cells to preserve cell stability while preserving concentrations. Within the cells proteins inject potassium ions into the cell.
By the amount layers the epithelial tissue has
