# Chloroplast --- A **chloroplast** is a bright green [[organelle]] found in [[plants|plant cells]] that performs [[photosynthesis]], turning sunlight into sugars. One plant leaf typically contains 40-50 chloroplasts. ![[chloroplast.png]] Chloroplasts are essentially [[bacteria|cyanobacteria]] that have moved into plant cells through [[endosymbiosis]]. ## Features Chloroplasts have an inner and outer membrane, and the interlying intermembrane space. ### Stroma & Granum The **stroma** is a fluid inside the inner membrane. This is where the [[adenosine triphosphate]] is generated by using the [[proton motive force]] of the proton gradient built up in the [[#lumen|thylakoid lumens]]. The **granum** are these stack-of-coin like structures that you can see, made up of many stacked [[#Thylakoid|thylakoids]]. #### Thylakoid **Thylakoids** are the little sac-like structures that make up the granum. The thylakoid membrane is where the [[light dependent reactions]] happen and the [[ETC (chloroplast)]]. The inside space of the thylakoid is its **lumen**, and this is where the proton gradient is built up. ##### Pigments The membranes of the thylakoids are full of **[[pigment|pigments]]** that give it that green color and act to power up [[photosynthesis]]. ## What Takes Place in the Chloroplasts? ### The Light Dependent Reactions The [[light dependent reactions]] ### The ETC The [[ETC (chloroplast)|ETC]] takes place in the membrane of the thylakoids. ___