NB: This is a BIOLOGY (SEPARATES) ONLY lesson
Growing bacteria in the lab lesson created in accordance to the NEW AQA Specification (9-1). Includes: slide animations, embedded videos, differentiated questions and answers have also been included within the slides. This resource is NOT suitable for combined science students.
AQA spec link: 22.214.171.124
Relevant chapter: B5-Communicable diseases . AQA Biology third edition textbook-Page 78-79.
Bacteria multiply by simple cell division
(binary fission) as often as once every 20 minutes if they have enough nutrients and a suitable temperature.
Bacteria can be grown in a nutrient broth solution or as colonies on an agar gel plate.
Uncontaminated cultures of microorganisms are required for investigating the action of disinfectants and antibiotics.
Students should be able to describe how to prepare an uncontaminated culture using aseptic technique.
They should be able to explain why:
• Petri dishes and culture media must be sterilised before use to kill unwanted microorganisms
• inoculating loops used to transfer microorganisms to the media must be sterilised by passing them through a flame
• the lid of the Petri dish should be secured with adhesive tape to prevent microorganisms from the air contaminating the culture, and stored upside down
• in school and college laboratories, cultures should be incubated at a maximum temperature of 25 °C.