Microbial Growth In pH + Osmotic Pressure Flashcards
Why are many foods preserved in acidic solutions?
Most bacteria cannot survive in acidic solutions
6.5-7.5 is the pH range that allows bacterial survival for extended periods of time
What are Acidophiles?
Bacteria with tolerance to low pH. (have industrial uses)
Why do commercial bacterial medias contain buffers?
To keep acid build up from interfering with growth
Why is an isotonic solution best for the survival of a bacterial cell
Flow of nutrients and water in and out of the cell is inhibited.
What will happen to a bacterial cell placed in a hypertonic solution?
Plasmolysis (Water running out of the cell causing it to shrivel)
What percentage of water do bacterial cells need to maintain?
70-80%
What are Halophiles?
Bacterial cells adjusted to survive in high salt concentrations
What will happen to a bacterial cell placed in a hypotonic solution?
Cell lysis (Hydrolysis) from water running into the cell until it bursts.
What is osmotic pressure?
The force that prevents a solvent from moving across the membrane
