Meselson and stahl actually let their experiment run for a fourth generation with cultures growing in the presence of 14n. explain what data from third- and fourth-generation dna should look like—that is, where the dna band(s) should be.

Salmonella typhimurium is a food-borne bacterial pathogen that can cause severe gastrointestinal disease. salmonella is often phagocytosed by macrophages that normally destroy bacterial pathogens, but this bacterium is somehow able to prevent the complete maturation of phagolysosomes. salmonella is able to tolerate the low ph of phagolysosomes, and in fact responds to the drop in ph by secreting toxins that interfere with other cellular responses. which of the following differences would you expect to contribute to the survival of a bacterium within an salmonella-containing phagosome, compared to a healthy phagolysosome? decreased activity of acid hydrolases increased activity of acid hydrolases decreased import of h+ ions increased import of h+ ions my guess is decreased activity of acid hydrolases but i'm not sure.

How can antibodies "remember" a particular bacterial invader or "antigen" on that invader?

Give examples of selective advantage of organism’s body part/organ