Chloroplasts are crucial organelles in plant cells responsible for photosynthesis, the process by which plants convert light energy into chemical energy. They contain the green pigment chlorophyll, which captures sunlight and facilitates the transformation of carbon dioxide and water into glucose and oxygen. This process is vital not only for plant growth but also for providing energy and oxygen to other organisms in the ecosystem. Without chloroplasts, plants would be unable to produce their own food, leading to significant impacts on ecosystems and the hierarchy of life.