Why there are only seven crystal why not other number

Imagine that you have produced several versions of lactase, each of which differs from normal lactase by a single amino acid. describe a test that could indirectly determine which of the versions significantly alters the three-dimensional shape of the lactase protein.

The first element on the periodic table of elements is carbon. a. true b. false

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.