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 trna®ln. 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 ironically with the nearby backbone phosphates. a. amino acids with polar uncharged side chains b. amino acids with negatively charged side chains c. amino acids with positively charged side chains d. amino acids with hydrophobic side chains

Biology ! the conversion of inorganic carbon to organic carbon by plants during photosynthesis is known as _[blank]_. filtration immigration reabsorption primary production

How do plants obtain more sunlight a.) they lean towards the light b.)they grow straight up c.) they only live in sunny areas, like the tropics d.) they stay low to the ground

Astudy by solloch and et. al., in 2017, gives the map above which shows the frequency of alleles with a ccr5-delta32 mutations over 87 different countries. this mutation deletes the presence of a co-receptor (ccr5) on the outside of human t-cells (lymphocytes). some viruses, such as the one responsible for the black death and human immunodeficiency virus (hiv), require this receptor for attachment to host cells during the infection process. the black death was an epidemic that passed over northern europe during the 14th century killing nearly 60% of europeans. according to this information, which explanation best explains why northern europeans show a greater immunity for hiv than some other parts of the world?