Here's a breakdown:

* Gametophyte: The haploid (containing one set of chromosomes) stage in the plant life cycle.

* Gametes: Specialized reproductive cells, such as sperm and egg cells, which fuse during fertilization to create a zygote.

* Zygote: The first cell of a new diploid (containing two sets of chromosomes) sporophyte generation.

In summary, the gametophyte is responsible for producing the sex cells (gametes) that will eventually lead to the formation of a new sporophyte.