An organelle is a specialized part of a cell that performs a specific function, somewhat analogous to an organ in a body. Both animal and plant cells contain organelles, although there are a number of differences.
Examples of organelles include the cell nucleus, which stores genetic information and controls cellular activities, ribosomes, which synthesize proteins, mitochondria, which provide energy for the cell, and lysosomes, which contain enzymes that break down waste materials and cellular debris. Chloroplasts, a type of organelle that is found only in plant and some algae cells, are responsible for photosynthesis, the process in which light energy is converted into chemical energy stored in glucose.