TRNA synthetases play a key role in protein biosynthesis by catalyzing the specific aminoacylation of tRNA at their 3' ends, a two step reaction termed "charging" of tRNA. The tutorial depicts the binding of glutaminyl-tRNA synthetase and tRNAGln. A uracil (U35) provides a key element for the recognition of tRNAGln by the synthetase enzyme. U35 of the tRNA is anchored in place by specific amino acids in the synthetase protein interacting ionically with the nearby backbone phosphates. Given what you know about ionic bonds and the phosphate backbone of RNA, what type of amino acids are involved in this interaction

What protects the lining of the stomach from acidic gastric juices?

Keeping in mind the life cycle of bacteriophages, consider the following problem: during the reproductive cycle of a temperate bacteriophage, the viral dna inserts into the bacterial chromosome where the resultant prophage behaves much like a trojan horse. it can remain quiescent, or it can become lytic and initiate a burst of progeny viruses. several operons maintain the prophage state by interacting with a repressor that keeps the lytic cycle in check. insults (ultraviolet light, for example) to the bacterial cell lead to a partial breakdown of the repressor, which in turn causes the production of enzymes involved in the lytic cycle. as stated in this simple form, would you consider this system of regulation to be operating under positive or negative control?

How would you describe the the organisms in the second row of model 1 that are connected to the parents by a line