1. Some bacteria exhibit auxotrophy, requiring specific nutrients to survive.
一些细菌表现出生长所需的营养物质的外源性要求，需要特定的营养物质才能存活。

2. The study of auxotrophy in yeast has contributed to our understanding of cellular metabolism.
对酵母的外源性营养依赖性的研究有助于我们理解细胞代谢过程。