Do prokaryotic cells have any particular method of resisting changes in the envi.?

Answer 1

a) endospores, as the answerer above has said!
b) some are equipped with flagella, and can swim away from an unfavorable environment or toward a favorable one. This is interesting to watch -- dab E. coli into a dish of liquid medium, and over the next few hours, the E. coli will swim away from the center as they use up the nutrients and make waste products. Their movement forms a visible ring!
c) Those equipped with sex pili or pili receptors can exchange plasmids with other bacteria that have the corresponding complementary equipment. In this way, such things as resistance to antibiotics may be passed, even between different "species" of bacteria.

Answer 2

Boy do they ever! In addition to those listed by the other answers here are a few more to consider:

1. The "SOS" response. When bacteria sustain tremendous DNA damage the SOS program kicks in. Regulated by the recombinase RecA and the transcriptional repressor LexA, the SOS response kicks DNA repair mechanisms in high gear, and also mobilizes the "last resort" mutagenic bypass polymerases to deal with the damage.

2. Quarum Sensing. Bacteria in solution can communicate with each other (typically within a species) about environmental conditions. By releasing short peptides the bacteria can signal their colony to stop or restart growing based on the concentration of those peptides in the media.

3. Osmotic Pressure Regulation. Most people think that the cell wall keeps proks. from worrying about osmotic pressure but that's just not true! Coli uses an entire family of polyamines (primarily betaene) to regulate osmotic pressure and prevent osmolysis.

4. Biofilm formation. Not an expert on this by any means but look into it if you're interested.

5. Lateral gene transfer. Bacteria can share useful mutations by exchanging plasmids.. hence antibiotic resistance!

Answer 3

If by "resisting" you mean "withstanding", bacteria can wait until better conditions by forming endospores. See this site for more information about endospores.