ピレノイドMeanings1nounpyrenoidA structure found in the chloroplasts of certain algae and hornworts, involved in carbon fixation. Technical term used in biology.ピレノイドは藻そう類るいの葉よう緑りょく体たいに見みられる構こう造ぞうです。Pyrenoids are structures found in the chloroplasts of algae.