Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

10 Cards in this Set

  • Front
  • Back
What are the problems faced by microorganisms at low temperatures?
Lipid membranes become semi-crystalline and lose intregrety at low temperatures, enzyme activity becomes very slow, ice crystal formation can disrupt cell structure
What are the problems faced by microorganisms at high temps?
Temp increases, membrane fluidity alters slowly, membrane integrity is lost in fluid and semi crystalline starts.
How do properties of membrane lipids help microorganisms over come the problems imposed by hot and cold environments
Lipid concentration- is rich in poly unsaturated fatty acids.

Cyroprotectants- enhance cold tolerance, agents prevent the formation of ice crystals
What role do cyroprotectants in adaptation? How do cyroprotectants differ from solutes made by hyper thermophilic microbes
Cyroprotectants- enhance cold tolerance, they are agents to prevent the formation of ice crystals.

Hyperthermophiles- have solutes that stablize proteins at higher temperatures, most have high internal salt concentrations and some have histone like proteins that help stabilize DNA
like higher temperatures and has optimal growth temperatures at the enhanced temp. It also follows that there enzymes and proteins will funtion optimally at the enhanced temperature.
organism can survive higher temps but its optimal growth will be in a more moderate temperature range. Enzymes and proteins will function optimally at the enhanced temperature
optimal temps at 15 C or below and maxium growth temp 20 C and a minimum growth temp of 0 C or below. May be killed off even by brief exposure to higher temperatures.
Organisms grow at 0 C, but have an optima of 20-30 C
Have optium above 75 C and can grow at temperatures above the BP of water.
Sterilization by Heat Treatment
Most commonly used methods to control microbial growth. Cells are exposed to moist heat under pressure. Typical condtions are to heat @ 1.1Kg/Cm2 on 15 lbs/in2 pressure for 10-15 minutes result in a temp of 121 C, high temp kills microbes.