Chloroplasts ... double membrane bound organelle in plants, responsible for photosynthesis, oxygen evolution and CO2 reduction (dark reactions).
     
number per cell = roughly 50
     
shape is variable: oblate spheroid, stellate, reticulate, etc...
     
size: 2-3 microns by 5-10 microns
     
contents
include contents a liquid STROMA (chloroplasm) that holds:
            
1) 70s ribosomes (bacterial size)
            
2) lipid droplets
            
3) naked DNA pieces (supercoiled & repetitive)
            
4) starch granules (pyrenoids)
            
5) enzymes of CO2 fixation (reduction)
      and an
internal membrane system of THYLAKOID membranes, which
              enclose a lumen.
Stacked arrays are called GRANA (resembling a
            stack of coins).
      Four types of protein assemblies are embedded in the thylakoids
              
Photosystem I which makes NADPH
              
Photosystem II which which splits water & makes ATP
              
ETC components as Cytochromes b and f
             
ATP synthase
These assemblies carry out the light reactions of photosynthesis.