Teaching sequence

Lesson objective

In this lesson students identify the characteristics of bacteria, examine how the discovery of penicillin affected society and look at the role of microbiologists in the modern world.


Discuss with students what germs and bacteria are. Discuss the food-handling regulations that exist in Australian states and territories. Ask why people who are sick should not handle food.


  1. Students complete the worksheet Food handling standards and cell theory.
  2. Discuss the size of bacteria. Are they bigger or smaller than human cells? Are all human cells the same size?
  3. Complete the activity From coffee to carbon. Hint: an antibody is a molecule that animals produce to fight disease; adenine is part of a DNA molecule; and phospholipid molecules make up a cell membrane. If your students will not understand these references, then remove them from the card set. Use the learning object Cell size and scale to help students with the concept of scale.
  4. Ask students if they have ever had antibiotics. (Antibiotic molecules are a similar size to the antibody pictures in the previous activity.) Ask if they know how the antibiotics kill bacterial cells.
  5. Describe what could happen to someone who had an infected scratch before penicillin was discovered.
  6. Watch the video 100 greatest discoveries: penicillin
  7. Students complete the worksheet The importance of penicillin.
  8. Ask students how they would tell the difference between the different types of bacteria and fungi that can cause infections.
  9. Watch the videos A tour of a microbiology laboratory and A day in the life – Microbiology/Virology – Prof Bill Rawlinson
  10. Place students into pairs. One student should be the interviewer and the other a microbiologist. What questions would they ask? What answers would the microbiologist give?


Watch the video Interview with a medical microbiologist

Lesson Resources


Student activities

Digital resources

Cell size and scale, Genetic Science Learning Centre, University of Utah. (Link updated: 16 December, 2016.)

100 greatest discoveries: penicillin, How stuff works. Videos (2:22 min) 

A tour of the microbiology lab, YouTube (8:11 min) 

Day in the life – Microbiology/Virology – Prof Bill Rawlinson, YouTube (5:08 min) 

Interview with a medical microbiologist YouTube (12:11 min) 


Food handling and cell theory (Word, 396 KB)

From coffee to carbon, Genetic Science Learning Centre, University of Utah (PDF) 

The importance of penicillin (Word, 403 KB) 

Useful links

Careers in plant pathology, APSnet. Information 

Food Safety Standard 3.2.2 – Food safety practices and general requirements, Food Standards Australia and New Zealand. Fact sheet 

How penicillin kills bacteria, Cells Alive! Film clip (00:08 min) and facts 

Howard Florey: the story. Maker of the miracle mould, ABC Science. Article