Thylakoid

Thylakoids (from Greek θύλακος thylakos "bag" ) are in biology membrane systems that occur in the chloroplasts of plant cells or in phototrophic bacteria and in which there is the light reaction of photosynthesis.

In Protocyten thylakoids arise from inward invaginations of the cytoplasmic membrane, which is typically located near the inside. Inside the chloroplasts of green plant thylakoids also arise from membrane invaginations, namely on the inner chloroplast membrane. You run through the chloroplast interior, known as the stroma.

Also in other plant plastids, which can be derived from Protocyten, thylakoids occur.

Granum

In chloroplasts money roll-like lamellar stacks, called grana (from Latin granum " grain ", pl. Grana ) formed by superposition of disk-shaped Thylakoidauslappungen. They are called grana forming Thylakoidauslappungen Granathylakoide; they have a very high pigment content. The Thylakoidteile which do not run in the grana, but singly in the stroma are called Stromathylakoide; they contain less pigment and are not as strongly involved in the light reaction in photosynthesis.

Construction

Thylakoids consist of a membrane enclosing an interior lumen. In the membrane are the light -harvesting complexes.

The Granathylakoide contain in their membrane particularly large number of light -harvesting complexes ( photosystem I and photosystem II) and continue cytochrome b6f complexes, ATP synthase, plastoquinone, plastocyanin, ferredoxin and NADP reductase, all of these are protein molecules. In the lumen there are chlorophyll molecules, carotene molecules and phospholipid molecules. The pH of the lumen is approximately 4

• Cellular component
• Photosynthesis