The elimination of 5−bromononane on treatment with potassium ethoxide is stereoselective. select the correct newman projections of 5−bromononane showing the conformations that lead to cis−4−nonene and trans−4−nonene, respectively. identify the proton that is lost in each case by selecting the newman projections that have this hydrogen colored blue. suggest a mechanistic explanation for the observed stereoselectivity. leads to cis−4−nonene:

Effect of rotenone and antimycin a on electron transfer rotenone, a toxic natural product from plants, strongly inhibits nadh dehydrogenase of insect and fish mitochondria. antimycin a, a toxic antibiotic, strongly inhibits the oxidation of ubiquinol. (a) explain why rotenone ingestion is lethal to some insect and fish species. (b) explain why antimycin a is a poison. (c) given that rotenone and antimycin a are equally effective in blocking their respective sites in the electron-transfer chain, which would be a more potent poison? explain.