Like heterotrophic cells, autotrophic cells have a nucleus, containing the cell's DNA. Also, the cell contains membrane-bound organelles and is bound by a cell membrane consisting of phosphates and lipids, interspersed with proteins and carbohydrates. The membrane-bound organelles include the Golgi apparatus (responsible for packaging materials that the cell produces), the lysosomes (the digestion centers of the cell), the mitochondria (produce energy in the cell) and the ribosomes (on which protein is synthesized).
Unlike heterotrophic cells, autotrophic cells are surrounded not only by a cell membrane, but also by a stiff cell wall, made of cellulose. The cell wall helps to strictly maintain the structure of the cell. As well, it keeps water pressure levels within the cell at acceptable limits. Plant cell walls consist of up to three different layers. The lamella, the outermost layer, glues adjacent plant cells together. The primary cell wall, located adjacent to the cell membrane, is thin and flexible, and forms while the cell grows. The secondary cell wall, found within some cells, strengthens and waterproofs the wall.
Most autotrophic cells, but few heterotrophic cells, have vacuoles. Vacuoles generally are much larger in autotrophic cells than they are in heterotrophic cells. Vacuoles consist of a membrane surrounding a mass of fluid. They are either used to store food products and nutrients, or they are used to hold water and, along with the cell wall, maintain the turgor pressure of the cell. The stability that vacuoles and the cell wall provide allow plant cells to grow to a much greater extent than animal cells.
Autotrophic cells contain chloroplasts, which allow autotrophs to produce their own energy. Chloroplasts contain green pigment (chlorophyll) that captures light, along with thylakoid membranes and grana, where photosynthesis takes place. When light hits chlorophyll, electrons are "knocked off" the chlorophyll molecule, and they split water into two hydrogen atoms and one oxygen atom. These electrons fall down an energy hill, and in the process, they make energy. These light-dependent reactions are of the utmost importance to producing plant energy.