It is important to use sterile apparatus when working with micro-organisms - Leaving Cert Biology - Question 7 - 2008
Question 7
It is important to use sterile apparatus when working with micro-organisms.
(a) (i) What is meant by sterile?
(ii) How may apparatus be sterilised?
(b) Answer th... show full transcript
Worked Solution & Example Answer:It is important to use sterile apparatus when working with micro-organisms - Leaving Cert Biology - Question 7 - 2008
Step 1
What is meant by sterile?
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Answer
Sterile refers to being free from microorganisms or living things. This means that the equipment or surface does not contain any bacteria, viruses, fungi, or other forms of life.
Step 2
How may apparatus be sterilised?
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Answer
Apparatus can be sterilised using methods such as autoclaving, where temperatures exceeding 100°C are used, boiling, steam treatment, or by using anti-bacterial agents or UV light.
Step 3
Name the container in which you grew the leaf yeast.
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The leaf yeast was grown in a Petri dish or agar plate.
Step 4
What was present in this container to provide food for the yeast?
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The container contained nutrients or malt agar that provided the necessary nourishment for the yeast to grow.
Step 5
Describe how you put leaf yeast into the container.
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To introduce the leaf yeast, I used a clean cork borer to cut pieces of a leaf, ensuring that I used sterile forceps to handle the leaf. The leaf was then attached to the upper surface of the agar, often using petroleum jelly on the inside of the lid to maintain sterility.
Step 6
How long did it take for the leaf yeast to appear?
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The leaf yeast took more than 2 days or approximately 24 hours to appear.
Step 7
Describe the appearance of the leaf yeast in the container.
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The leaf yeast appeared as pink dots or colonies, with a reference to their distribution across the agar.
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