1.7 Growing and investigating bacteria

Question 1

What is bacteria grown on in a lab?

Answer 1

Agar jelly in a petri dish

Question 2

Why must all the materials and equipment used to grow bacteria in a lab be sterilised?

Answer 2

If not sterile, the culture can become contaminated, may even contain pathogens.

Question 3

What can contaminate cultures grown in the lab?

Answer 3

skin, air, soil, water

Question 4

What are cultures of bacteria used for?

Answer 4

laboratory investigations, ge to find the effects of antibiotics on bacteria

Question 5

What is in agar?

Answer 5

nutrients for the mircrogoranisms to grow, that is:

Carbohydrates - an energy source

minerals

Sometimes other chemicals

Question 6

What conditions should be provided when growing cultures

Answer 6

Warmth and oxygen, 25 degrees C in schools and 35 degrees in labs (Will grow faster at 35 but is harder to maintain this temperature)

Question 7

How do you make sure that unwanted microorganisms do not contaminate a pure culture of bacteria?

Answer 7

Heat all equipment, boil solution, cover petri dishes or flasks, pass inoculating loop through a flame. (do not recontaminate equipment after sterilizing but putting it down on the desk, or blowing on it