Study Guide

• what is an organism with an organic e- donor?

  organotroph
• why do some microbes require oxygen?

  use it in their metabolism
• how can some microbes live with or without oxygen?

  don't require for metabolism and have enzymes to deal with reactive byproducts
• what can you count to measure cell growth?

  cell number or colonies
• how does turbidity measure cell growth?

  optical density increases with cell number
• how do cold temperatures affect growth rate?

  slow enzyme rate
• how do hot temperatures affect growth?

  denature proteins
• what organisms accumulate compatible solutes to combat osmotic pressure?

  halophiles and osmophiles
• what are two types of sterilization used in physical growth control?

  filter and radiation
• what are 4 methods used in temperature growth control?

  1. moist heat
  2. dry heat
  3. refrigeration
  4. pasterurization
• what are three ways cells react to nutrient starvation?

  • inclusions for nutrient storage
  • energy source storage
  • carbon storage