Meanings of first eukaryote in English

This means that the first eukaryote must have formed when a host cell swallowed a bacterium.

The consensus view is that the first eukaryotes appeared about 2 billion years ago.

But how did the first eukaryotes gain their mitochondria?

That means the very first eukaryotes must have been getting a boost in the form of tiny sausage-shaped structures called mitochondria that generate energy.