Cells are the basic and fundamental unit of life. All organisms are made up of cells. They may be made up of a single cell (unicellular), or many cells (multicellular).
The Video produced by Nucleus explains you structure and various functions of plant and animal cells in an animation, including organelles like the nucleus, nucleolus, DNA (chromosomes), ribosomes, mitochondria, etc. Also the video discusses ATP molecules, proteins, microtubules, cytoskeleton, cytoplasm, chloroplasts, chlorophyll, cell walls, cell membrane, cilia, etc.