Genetic control of metabolism in microorganisms Flashcards
Why are micro-organisms used for research or industry?
They are easy to culture, reproduce and grow quickly, food substrate often cheap, produce useful products, can easily manipulate their metabolism
What are two types of growth mediums commonly used in the lab?
Nutrient agar and nutrient broth
What techniques are used when culturing micro-organisms to maintain sterile conditions?
Aseptic techniques
Why is it important to maintain sterile conditions when working with micro-organisms?
To prevent contamination which could affect the growth of the microorganism
Which piece of machinery is used when culturing micro-organisms on a large scale?
Fermenter
Which factors can affect the growth of micro-organisms?
Temperature, oxygen concentration, pH, glucose concentration
What is provided to micro-organisms in a simple growth media?
Energy source (if not photosynthetic) and simple chemical compounds for biosynthesis of molecules required for growth.
Why do some micro-organisms require more complex growth media like beef extract?
They are unable to synthesis molecules necessary for growth without extra vitamins and fatty acids.
What can be used to control pH in an experiment /fermenter?
Buffers
What are the four phases of microbial growth?
Lag phase, log phase, stationary phase, death phase.
What is meant by “doubling time” or “generation time” in terms of growth of micro-organisms?
The time needed for a population to double
What happens during the lag phase?
Micro-organisms induce enzymes required for growth and synthesis molecules necessary for growth.
What happens in the log phase?
The cells divide at their maximum rate
What happens during the stationary phase?
The birth rate = the death rate due to nutrients running out and a build-up of secondary metabolites, some of which are toxic
What happens in the death phase?
Toxic metabolites and lack of substrate leads to more cells dying than are being produced.
