<P> Chloroplasts / ˈklɔːrəˌplæsts, - plɑːsts / are organelles, specialized compartments, in plant and algal cells . Their discovery inside plant cells is usually credited to Julius von Sachs (1832--1897), an influential botanist and author of standard botanical textbooks--sometimes called "The Father of Plant Physiology". </P> <P> The main role of chloroplasts is to conduct photosynthesis, where the photosynthetic pigment chlorophyll captures the energy from sunlight and converts it and stores it in the energy - storage molecules ATP and NADPH while freeing oxygen from water . They then use the ATP and NADPH to make organic molecules from carbon dioxide in a process known as the Calvin cycle . Chloroplasts carry out a number of other functions, including fatty acid synthesis, much amino acid synthesis, and the immune response in plants . The number of chloroplasts per cell varies from one, in unicellular algae, up to 100 in plants like Arabidopsis and wheat . </P> <P> A chloroplast is a type of organelle known as a plastid, characterized by its two membranes and a high concentration of chlorophyll . Other plastid types, such as the leucoplast and the chromoplast, contain little chlorophyll and do not carry out photosynthesis . </P>

What does a chloroplast do in a plant cell