Gịnị ọzọ ka a na-akpọ fret? N'iburu ajụjụ nke mbụ n'uche, dee ihe gbara ya gburugburu bụ́ nke ga-enye azịza ya. Ọ nwere ike ịbụ 1 - 20 ahịrịokwu. Ihe ndị gbara ya gburugburu:
N'ụdị helical thylakoid, grana mejupụtara nchịkọta nke flattened circular granal thylakoids nke yiri pancakes. Otu granum nwere ike ịnwe ebe ọ bụla site na abụọ ruo otu narị thylakoids, ọ bụ ezie na grana nwere 10<unk>20 thylakoids bụ ihe a na-ahụkarị. A na-eke gburugburu grana bụ helicoid stromal thylakoids, nke a makwaara dị ka frets ma ọ bụ lamellar thylakoids. Helices na-arịgo n'akuku nke 20<unk>25°, na-ejikọ na thylakoid ọ bụla na-ejikọta n'otu njikọ dị ka àkwà mmiri. Helicoids nwere ike ịgbatị dị ka nnukwu mpempe akwụkwọ na-ejikọ ọtụtụ grana, ma ọ bụ dị warara ka tube-dị ka àkwà mmiri n'etiti grana. Ọ bụ ezie na akụkụ dị iche iche nke usoro thylakoid nwere protein akpụkpọ ahụ dị iche iche, akpụkpọ ahụ thylakoid na-aga n'ihu na oghere thylakoid ha na-eme ka otu labyrinth na-aga n'ihu.