CMMB 343 Lecture 7: Extremophiles — Part 3
28 Jan 2019
School
Course
Professor
Document Summary
Water will move into the cell causing the water pressure to increase. Solute and pressure have cancelled each other out when in = out. Bacterial cells tend to be under lots of pressures, therefore need strengthened cell walls. Halophiles (salt) bacteria and archaea (and possibly fungi) Organisms adapted to freshwater are not halophiles. 3. 5% w/wis the most salt a halophilic bacteria can handle. Slight or mild halophile: 1-7% optimum (usually 3. 5%) Question: a bacterium is sitting in an isolated tidepool (3. 5% salt). Because, the rain downpour increases water potential outside the bacterial cell. Therefore, water will move into the cell (high water potential to low water potential). Moreover, the relationship between solute concentration and water potential is inverse, therefore, in the cell there is a higher solute concentration than there is water potential. So, to balance the water potential between the external and internal environment of the cell, water needs to move in, and solute needs to be excreted.
