1. The three conditions yeast needs during fermentation are acidity, moisture, and temperature.

2. Yeast can grow in the pH range of 0 to 5, and the optimal pH value is 5 to 0.

3. It is like bacteria. Yeast must have water to survive, but yeast needs less water than bacteria. Some yeasts can grow in environments with very little moisture, such as honey and jam. indicating that they have a fairly high tolerance to osmotic stress.

4. Yeast (saccharomyce) is a commonly used eukaryotic receptor cell in gene cloning experiments. Cultivating yeast is as convenient as cultivating E. coli.

5. There are many types of yeast cloning vectors.

6. Yeast also has plasmids. This 2μm long plasmid is called a 2μm plasmid and is about 6300bp.

7. This plasmid exists outside the chromosome in the nucleus at least for a period of time. Using the 2μm plasmid and the plasmid in E. coli, a shuttle plasmid can be constructed that can shuttle between bacteria and yeast cells.