A substance that slows down or stops the growth of microorganisms, such as bacteria.

A Petri dish containing a growth medium solidified with agar jelly, used for culturing microorganisms.

The clear area around an antimicrobial disc on an agar plate where bacterial growth has been stopped.

Practical methods used to prevent contamination by unwanted microorganisms.

The effect of antimicrobial substances on bacterial growth: analysis and conclusions

Biology

Pupils learned about human and plant defences against pathogens, the role of white blood cells in the human immune system, and the use of vaccination to protect against communicable diseases.

This unit covers vaccines, medicines, and monoclonal antibodies for disease prevention and treatment. It explains aseptic techniques, medicine development, and antibody uses. The focus is on ethical considerations, risk evaluation, and societal impacts of scientific advances.

Medicines and new treatments for disease

Physical activity and equipment requiring safe use

areas where bacteria can not grow or have been killed

areas where the antiseptic has covered via active transport

What are the clear areas around the paper discs?

Take a sample of bacteria from the patient. 

Grow the sample bacteria on an agar plate in culture.

Add antibiotic discs to the bacteria and culture the plate again.

Compare the sizes of any clear zones of inhibition around the discs.

Put these steps in order to show how you would test which antibiotics should (and should not) be used to treat a patient's disease.

The area of the zone of inhibition is {{}} mm².

Which antibiotic are bacteria resistant to?

Which antimicrobial is the least effective?

What letter represents the radius of this circle?

Using a value of 3.14 for 𝜋, calculate the area of this circle.

sterilises the wire to avoid contaminating the bacteria bottle

prevents unwanted microorganisms from settling on the agar

Match the aseptic technique to its reason.

Lucas: You shouldn't use a Bunsen burner because you could burn yourself.

Sofia: You should use a Bunsen burner so microorganisms in the air won't settle.

Laura: You should use a Bunsen burner to kill bacteria in your agar plate.

Jun: You shouldn't use a Bunsen burner as agar is flammable.

The Oak pupils are discussing aseptic technique. Who is correct? 

Which variables should be controlled in the investigation into the effect of antimicrobial substances on bacterial growth.

Content guidance

Risk assessment required - equipment

Adult supervision required

Introduction

What will you need for this lesson?

Are you ready to learn?

Equipment

Content guidance

Supervision

Worksheet