Physical variable on growth

Physical variable on growth

1. Temperature

   • Maxima and Minima- Range of growth
   • optimum- Best temp for growth

2. Adaptation for cold

   • Fluid membrane
     • flexible enzymes
   • efficient DNA repair
   • Protective solutes

3. Adaptions to hot

   • increased H bonding
     • Thermostable proteins
   • Chaperons
   • High G and C content
     • gyrase= supercoils

4. hyperthermophiles( Archea)

   • ester bonds
   • monolayer memebrane

5. Acidophiles

   • optima 6(pH)
     • obligate

6. Alkanlinphiles

   • pH 9 optima
   • Cyanobacteria
   • Use Na+ /H+ to regulate pH

7. Halophiles(high salt)

   • Produce compatible solutes
   • Extreme require Na+ and K+ to grow

8. Hydrostatic Pressure: high pressure inhibits enzymes

9. Oxygen

   • obligate aerobe ( require air)
   • obligate anaerobe ( air sensitive)
   • Facultative anaerobe: ferment or respire
   • Microareophiles: Low O2, can grow without
   • Aerotolerant anaerobe: ferment only

10. fermentation

    • glycolysis
      • Pyruvate is fermented