practicals 5 & 6 in a test-tube

Practicals 5 and 6 are all about working with bacteria. You will be learning how to separate out the bacteria from a mixture, and how to then characterise these bacteria.

! IMPORTANT !

Practical 5 is divided into two parts. 

You will be doing the first part one week, and then because the bacteria you are working with need time to grow, you will be doing the second part of the practical the next week. 

During the next two weeks you will be:

• learning how to safely handle and manipulate microorganisms (using aseptic technique)
• using the microscope
• using various techniques to characterise bacteria such as the Gram Stain
• plating bacteria on agar plates to obtain single colonies
• testing bacteria for antibiotic sensitivity
• testing whether bacteria are anaerobic or aerobic
• determining viable cell counts

There is quite a lot to do for this practical

-  it is really important that you read your manual before you come 

so you have an idea about what you are doing.

Day 1 will be divided into the following activities:

Activity 1 : AT HOME READ YOUR MANUAL to learn how to safely handle microorganisms

Activity 2 : Separate out bacteria from an artificial mixture using streak plating, different incubation temperatures and selective media.  You will end up with agar plates on which you have streaked bacteria that you will have to leave to grow in various different conditions until next week. 

Activity 3 : Separate out bacteria from mushroom compost using streak plating, different incubation temperatures, anaerobic and aerobic growth conditions, heat treatment, and selective media. You will end up with agar plates on which you have streaked bacteria that you will have to leave to grow in various different conditions until next week.

Activity 4 : Test a known bacterial culture for antibiotic sensitivity
Activity 5 : Make your work space safe and tidy

Day 2 will be divided into the following activities:

Activity 1 : Interpret and describe the bacterial colonies that have grown on the agar plates you set up during activity 2 on day 1 (this was using the artificial mixture). Further characterise the bacteria using various tests such as the Gram Stain, Catalase test and Oxidase test.

Activity 2 :  Interpret and describe the bacterial colonies that have grown on the agar plates you set up during activity 4 on day 1 (this was using the mushroom compost). Further characterise the bacteria using the Gram Stain and calculate the number of viable bacteria that were present in the compost.

Activity 3 : Interpret the results from the antibiotic sensitivity test set up during activity 5 on day 1

Activity 4: Make your work space safe and tidy

That might sound like a lot but there should be enough time to get everything done.....if you have read your handbooks before you come that will really help you .....