Cell Theory and Prokaryotic Cell Structure (2B) Practice Test

Researchers isolated two bacterial strains from a hypersaline lake. Both strains grew well at 3.5 M NaCl, but only Strain H remained viable after rapid transfer to freshwater. Chemical analysis showed Strain H produced a thick extracellular polysaccharide layer and formed compact cell aggregates. When a gene required for polysaccharide export was knocked out, the mutant lost freshwater survival despite unchanged intracellular enzyme profiles.

Which evolutionary adaptation would be expected given the described conditions and results?

A lab compared a Gram-negative bacterium and a yeast cell after exposure to a β-lactam antibiotic that inhibits peptidoglycan cross-linking. Both were placed in hypotonic buffer for 10 minutes. The bacterium rapidly lysed, while the yeast remained intact. (Terms: peptidoglycan = bacterial cell wall polymer; hypotonic = lower solute concentration outside the cell than inside.)

Which feature best exemplifies cell theory as applied to prokaryotes in this setup?