Discover how these tiny living structures function!
Without the plant kingdom, life on Earth would be a very different prospect. This huge and diverse group of living organisms not only nourishes the vast majority of animal life with tasty, nutritious roughage, but it also replenishes our atmosphere with enough oxygen to keep us living and breathing. Quite simply, life on Earth depends on plants. There are a number of characteristics that make all living things ‘alive’. For instance, they require food for growth and development; they respond and adapt to their surrounding environments; they have a life cycle of growth, reproduction and death; and, importantly, they contain cells.
Discovered by Robert Hooke in the 1650s, plant cells are the building blocks of all plant life. Just like animal cells, they are eukaryotic, which means they contain a nucleus – a structure that acts as the cell’s ‘brain’ or command centre. Found in the nucleus is the plant’s genetic information, which is used to inform the rest of the cell which functions to carry out.
Everything inside the cell is contained within a thin, semi-permeable lining called the plasma membrane. Inside this membrane is a sea of cytoplasm, a gelatinous substance in which all the other parts of the plant cell are found – most of which have specialised functions.
These ‘expert’ structures have dedicated roles and are known as organelles, or ‘mini organs’. Surrounding the plasma membrane is a rigid outer cell wall made from a fibrous substance called cellulose.
Another characteristic of a plant cell is its large vacuole. This is an area filled with fluid and gas and it accounts for most of a cell’s mass. The vacuole swells with fluid to help maintain a cell’s shape. The tough cell wall is strong enough to withstand this increased pressure and ensures this organic ‘balloon’ doesn’t burst.