Vesicles are small, bubble-like structures found within cells. They are made of a lipid bilayer, similar to cell membranes, and serve various functions, such as transporting materials like proteins and nutrients. Vesicles can form naturally during processes like endocytosis, where the cell engulfs substances from its environment. These tiny containers play a crucial role in cellular communication and metabolism. For example, neurotransmitter vesicles release chemical signals in the nervous system, allowing neurons to communicate with each other. Overall, vesicles are essential for maintaining the proper functioning of cells and facilitating important biological processes.