thylakoid

[ thahy-luh-koid ]

noun

, Cell Biology.

1. a flattened sac or vesicle lined with a pigmented membrane that is the site of photosynthesis, in plants and algae occurring in interconnected stacks constituting a granum of the chloroplast, and in other photosynthesizing organisms occurring either singly or as part of the cell membrane or other structure.

thylakoid

/ thī′lə-koid′ /

1. A saclike membrane that contains the chlorophyll in cyanobacteria and in the chloroplasts of plant cells and green algae. In chloroplasts, thylakoids are arranged in stacks called grana.

Word History and Origins

Origin of thylakoid¹

1965–70; < German Thylakoid < Greek thȳlakoeidḗs resembling a bag, equivalent to thȳ́lak ( os ) sack + -oēidēs -oid

Example Sentences

When light hits a plant’s leaves, it shines on chloroplasts and into their thylakoid membranes.

From Science News For Students