Answer AND Explanation:
A steroid is an organic macromolecule that is biologically active with four rings arranged in a specific molecular configuration. Steroids are important components of cell membranes which alter membrane fluidity and act as signaling molecules. The two main types of steroids are corticosteroids and androgenic steroids like testosterone and estradiol.
Invasive exotic species are species that interfiere with the natural food chain and are usually foreign
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Answer:
In order to be useful in treating human infections, antibiotics must selectively target bacteria for eradication and not the cells of its human host. Indeed, modern antibiotics act either on processes that are unique to bacteria--such as the synthesis of cell walls or folic acid--or on bacterium-specific targets within processes that are common to both bacterium and human cells, including protein or DNA replication. Following are some examples.
Most bacteria produce a cell wall that is composed partly of a macromolecule called peptidoglycan, itself made up of amino sugars and short peptides. Human cells do not make or need peptidoglycan. Penicillin, one of the first antibiotics to be used widely, prevents the final cross-linking step, or transpeptidation, in assembly of this macromolecule. The result is a very fragile cell wall that bursts, killing the bacterium. No harm comes to the human host because penicillin does not inhibit any biochemical process that goes on within us.
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Explanation:
