When a peptide hormone reaches its target cell, which event happens next?

It binds itself to the receptors present on the surface of the cell membrane, which activates the enzymes present inside cell. Then It passes through the cell membrane and attaches itself to a receptor protein present in the cytoplasm. It passes on the signal to the secondary messengers inside the cell, which activate the receptors on the cell membrane.

Eukaryotic cells are theorized to have evolved from prokaryotes called the endosymbiotic theory. this explains that the most primitive eukaryotic cell engulfed a prokaryotic cell (by the process of phagocytosis) that is capable of cellular respiration and another prokaryotic cell that is capable of photosynthesis. these prokaryotic cells eventually became organelles and these organelles are the mitochondria and the chloroplast