Yes, PROKARYOTES is a Scrabble word!

Letter values in Scrabble US: P 3, R 1, O 1, K 5, A 1, R 1, Y 4, O 1, T 1, E 1, S 1.

Is it a valid word?

PROKARYOTES is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a unicellular organism having cells lacking membrane-bound nuclei; bacteria are the prime example but also included are blue-green algae and actinomycetes and mycoplasma