Key Area 2.6 Environmental control of metabolism in micro-organisms Flashcards
What are some examples of microorganism’s?
Archea, Bacteria, Some species of eukaryotes.
Why are microorganisms used by scientists?
They are:
- easy to culture
- reproduce quickly
- their food source is usually cheap
- they make useful products
What kinds of microorganism’s require light?
Photosynthesising cells, e.g. algae.
What does sterile mean?
Not containing contaminating microorganisms.
Why do you need sterile conditions in fermenters?
To reduce competition with desired micro-organisms and reduce the risk of spoilage of the product.
What are the environmental factors that affect microorganism growth?
Temperature
Oxygen concentration
pH
Glucose concentration
Why are oxygen and glucose concentrations important for growth?
Both are needed for aerobic respiration which generates ATP that is needed for cells to divide.
In a fermenter what is the function of steam at the start?
To sterilise the fermenter.
In a fermenter what is the function of cool water?
Controls the temperature.
In a fermenter what is the function of the rotating paddles?
To mix the contents.
In a fermenter what is the function of pH sensor/ buffer?
To maintain optimum pH.
In a fermenter what is the function of the oxygen that is added?
To allow aerobic respiration to occur and create ATP.
In a fermenter what is the function of the added glucose solution?
To allow aerobic respiration to occur and create ATP.
What happens at the lag phase and what does it look like?
Limited increase in cell number, enzyme are being induced. Flat line.
What happens at the log phase and what does it look like?
The most rapid growth occurs as there are plentiful nutrients. steep upward slope.
