<P> As a result, chloroplasts in C mesophyll cells and bundle sheath cells are specialized for each stage of photosynthesis . In mesophyll cells, chloroplasts are specialized for the light reactions, so they lack RuBisCO, and have normal grana and thylakoids, which they use to make ATP and NADPH, as well as oxygen . They store CO in a four - carbon compound, which is why the process is called C photosynthesis . The four - carbon compound is then transported to the bundle sheath chloroplasts, where it drops off CO and returns to the mesophyll . Bundle sheath chloroplasts do not carry out the light reactions, preventing oxygen from building up in them and disrupting RuBisCO activity . Because of this, they lack thylakoids organized into grana stacks--though bundle sheath chloroplasts still have free - floating thylakoids in the stroma where they still carry out cyclic electron flow, a light - driven method of synthesizing ATP to power the Calvin cycle without generating oxygen . They lack photosystem II, and only have photosystem I--the only protein complex needed for cyclic electron flow . Because the job of bundle sheath chloroplasts is to carry out the Calvin cycle and make sugar, they often contain large starch grains . </P> <P> Both types of chloroplast contain large amounts of chloroplast peripheral reticulum, which they use to get more surface area to transport stuff in and out of them . Mesophyll chloroplasts have a little more peripheral reticulum than bundle sheath chloroplasts . </P> <P> Not all cells in a multicellular plant contain chloroplasts . All green parts of a plant contain chloroplasts--the chloroplasts, or more specifically, the chlorophyll in them are what make the photosynthetic parts of a plant green . The plant cells which contain chloroplasts are usually parenchyma cells, though chloroplasts can also be found in collenchyma tissue . A plant cell which contains chloroplasts is known as a chlorenchyma cell . A typical chlorenchyma cell of a land plant contains about 10 to 100 chloroplasts . </P> <P> In some plants such as cacti, chloroplasts are found in the stems, though in most plants, chloroplasts are concentrated in the leaves . One square millimeter of leaf tissue can contain half a million chloroplasts . Within a leaf, chloroplasts are mainly found in the mesophyll layers of a leaf, and the guard cells of stomata . Palisade mesophyll cells can contain 30--70 chloroplasts per cell, while stomatal guard cells contain only around 8--15 per cell, as well as much less chlorophyll . Chloroplasts can also be found in the bundle sheath cells of a leaf, especially in C plants, which carry out the Calvin cycle in their bundle sheath cells . They are often absent from the epidermis of a leaf . </P>

Where do you find chloroplasts in a plant