Lab Set 3 Worksheet

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Labset Three Worksheet

1. What is a carbohydrate profile? Why are they used as a diagnostic or identifying tool? (2) Carbohydrate profiles are specific information on the type and amount of carbohydrate that a product contains. It is used to identify and differentiate two closely related species.

2.What are the carbohydrate profiles of the organisms you tested? (2) The yeast carbohydrate profile came out with glucose and fructose positive and Mannitol negative. The staph epidermidis was glucose, lactose and sucrose positive and mannitol negative.

3.Why is it important not to incubate the fermentation tubes more than 24 hours?(1) Because the sugar test will have a higher chance that the color will change and could alter the results to a negative instead of a positive and this would create an incorrect result.

4.What is osmosis? How does it affect microbial growth? (2) Osmosis is the diffusion of water molecules across a semi permeable membrane from a lower concentrated solution to a higher concentrated solution without using energy. Microbial growth requires control of nutrients and physical and chemical conditions in their environments. Osmosis effects growth by controlling the moisture of their environment. Other important factors that control growth are temperature, oxygen, pH, light and nutrients.

5. Define the following terms: (3)
Isotonic: Two solutions having the same osmotic pressure resulting in no movement of solvents across the membrane. Hypertonic: One solution having a higher concentration of a solute outside the cell resulting in movement of water to leave the cell. (Higher osmotic pressure) Hypotonic: One solution having a lower concentration of a solute than the inside of a cell resulting in water to enter the cell. (Lower osmotic pressure)

6.Write a lab report on experiment 9 with the following sections: (50) See drop box submission.
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