(a) (i) What term is used to describe asexual reproduction in yeast? (ii) Explain the term sterile as it applies in microbiology - Leaving Cert Biology - Question 7 - 2015

In microbiology, the term sterile refers to the absence of all living microorganisms, including bacteria, viruses, and fungi. Sterility is crucial for experiments and procedures to avoid contamination that could affect results.

The yeast was obtained from the leaves of any named tree or shrub, such as a maple or oak.

To keep the leaves free from contamination, I wore gloves while handling them. Alternatively, I could have used tweezers or placed the leaves into a plastic bag immediately after collection.

The nutrient medium used for growing the yeast was Malt agar.

The steps followed in the laboratory included:

1. Using an aseptic technique to handle the leaves or leaf sections.
2. Attaching the leaves or leaf sections to the lid of the Petri dish containing the Malt agar.
3. Incubating the Petri dish under suitable conditions.

Yeast was concluded to be present if pink colonies or colonies with a distinct color were observed on the culture medium, indicating yeast growth.

At the end of the investigation, any remaining material should be treated by autoclaving, incinerating, or soaking in a disinfectant to ensure that all microorganisms are killed before disposal.