单词是语言结构的基本单位。

Single words are the building blocks of language.

《牛津词典》

原子是元素最小的结构单位。

An atom is the smallest characteristic unit of an element.

youdao

在显微镜下，肝脏是由肝小叶为单位的网状结构。

When viewed under a microscope, the liver is seen as large network of units called hepatic lobules.

youdao

I do want to talk about one important subject which you might not have thought too much about and that's lipids, because lipids are so important to the structure of the body because they make up the membranes that form the cells that are the fundamental units.

我的确想要讨论一个重要的主题,这个主题也许你们都没有深入思考过,那就是关于脂类的问题,脂类对身体结构形成十分重要,它是组成细胞膜的基本单位,而细胞膜能够维持细胞形态

耶鲁公开课 - 生物医学工程探索课程节选

Estrogen can combine with this receptor to form a new sort of unit which interacts with DNA.

雌激素能够与受体相结合,形成一个新结构单位与DNA相互作用

耶鲁公开课 - 生物医学工程探索课程节选

So this is a monomer or a single unit from an RNA molecule, you know that because it's ribose and it's the particular molecule that has as its organic base.

所以这是一个RNA单体,即RNA上一个单独结构单位,你通过核糖,和碱基就能够确认它是RNA,这个RNA单体的碱基为A

耶鲁公开课 - 生物医学工程探索课程节选