chloroplasts

• are the site of photosynthesis in plant cells
• light energy is used to drive the reactions of photosynthesis in which carbohydrates molecules are made from carbon dioxide and water
• 4 to 10um in length
• found in plant cells and in some protoctists
• surrounded by an outer and inner membrane which are collectively described as the chloroplast envelope
• the inner membrane is continuous with stacks of flattened membrane sacs called thylakoid which contain the pigment chlorophyll.
• a stack of thylakoids is called a granum and this creates a large surface area for the absorption of light energy.
• the integranal lamella joins grana together
• the fluid inside the chloroplast is called the stroma. insoluble energy stores called starch grains and lipid droplets can be found here.
• chloroplasts have their own DNA and structures called ribosomes where proteins are made