counting bacteria

Question 1

How quickly does bacteria divide?

Answer 1

Very quickly

Question 2

How populated are bacteria cultures?

Answer 2

There are millions of bacterial colonies

Question 3

What is the problem with millions of bacterial colonies in a bacteria culture?

Answer 3

It is very difficult to count the number of bacteria
This is because colonies will overlap and clump together

Question 4

What method do scientists use to count bacteria?

Answer 4

Scientists perform a dilution series
They then multiply the dilution factor by the number of colonies seen to gain the number of bacteria in the original medium culture

Question 5

Steps of doing a dilution series to then count bacteria

Answer 5

1) Take 1 part of the original culture medium and mix in 9 parts sterile water to get a 1/10 dilution.
This divides the number of bacteria in the culture medium by 10.
2) You can continue this process to create a serial dilution.
By taking 1 part of the previous dilution and adding it to 9 parts of sterile water you can create a 1/100, This divides the number of bacteria in the original culture medium by 100.
3) Repeat until you are able to count the colonies of bacteria
4) Multiply the dilution factor by the amount of colonies visible to find the number of colonies in the original medium culture