(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. Sterile techniques are crucial in laboratory practices to ensure that cultures are not contaminated and that experimental results are reliable.

The yeast was obtained from the leaves of a specified tree or shrub, such as a grape leaf or any other suitable plant known for yeast presence.

To keep the leaves free from contamination, I wore gloves and handled the leaves with tweezers. Alternatively, I placed the leaves in a plastic bag immediately after collection to minimize exposure to environmental microorganisms.

The nutrient medium used to grow the yeast was Malt agar, which provides the necessary nutrients for yeast growth.

1. I attached the leaves or leaf sections to the inside of a lid of a petri dish.
2. I incubated the dish under suitable conditions to allow yeast growth.
3. After an appropriate incubation period, I observed the growth for any signs of yeast colonies.

I concluded that yeast was present by observing the culture for pink colonies or colonies described as pink, which indicated yeast growth.

Any remaining material should be treated by autoclaving, incinerating, or soaking in disinfectant solution to ensure that all microorganisms are effectively destroyed before disposal.