Week 4 Flashcards
What is the easy method for multiplying powers of 10?
Add the powers
What is the easy method for dividing powers of ten?
Subtract the powers
What is the easy method for subtracting powers of 10?
Divide the powers
What is the easy method for adding powers of ten?
Multiply them
How many nm in diameter is a red blood cell?
10000
How many nm in length is E.Coli?
3000
How many nm in length is Ebola?
970nm
How many nm in length is Adenovirus?
90nm
What is a viable count?
A sample is often diluted if it is too concentrated to allow a viable count. Used to investigate number of living cells in a culture.
What do serial dilutions allow for?
Countable investigation
What are spread plates used for?
To calculate how many bacteria are in a sample
What would the ideal dilution of a bacterial sample produce upon investigation?
30-300 colonies
In a sample of 1ml with a 10^-6 dilution, 250 Bacteria are present. What was the original bacterial colony?
Show your working out?
250 x10^6
2.5 x10^8
What is the difference in the bacterial count between a 1ml and a 0.1ml plate?
The 0.1ml plate will have a 10x greater bacterial count.
What are serial dilutions on bacteria?
Adding measured amounts of buffer to a bacterial solution to a level where they can be easily counted.
What is the formula for finding the amount of colony forming units per ml of a solution?
(Number of colonies x inverse dilution) / volume of sample
What is often used to identify the number of colonies in a very high cfu sample?
Log cfu/ml
Approximately how many species of Protozoa exist?
65000
Are most Protozoa pathogenic or not?
Not
Where do most Protozoa live?
Freely in the water or in the soil.
Describe the cellularity of most protozoa species.
Unicellular
What types of locomotive structures can protozoa contain?
Flagella, Cilia, Pseudopods
What is the motile feeding stage of the protozoan life cycle called?
Trophozoite
What is the dormant resting stage of a Protozoan life cycle called?
Cyst