Cell Structure

All living organisms on Earth are divided into cells. The main concept of cell theory is that cells are the basic structural unit for all organisms. Cells are small compartments that hold the biological equipment necessary to keep an organism alive and successful. Living things may be single-celled or they may be very complex such as a human being. There are smaller pieces that make up cells such as macromolecules and organelles. A protein is an example of a macromolecule while a mitochondrion is an example of an organelle. In larger organisms, the main purpose of a cell is to organize. If you were only made of one cell, you would be very limited. There are many types of cells. Plant cells are easier to identify because they have a protective structure called a cell wall made of cellulose. Cells are unique to each type of organism. Humans have hundreds of different cell types. Inside the Cell (Canadian Museum of Nature Video)

Microorganisms Let's study the wee ones of the world known as the microbes or the microorganisms. If you spend your life studying them, you would be a microbiologist. These are the smallest of the small and the simplest of the simple. What makes a microbe? It took one invention to change the way we see the world of microbes - the microscope. We'll give the big overview on the variety of microorganisms here. They can be heterotrophic or autotrophic. They can be solitary or colonial. They can reproduce sexually or asexually. Plants If you're not a microbe and you're not an animal, you are probably a plant. There are about 300 thousand known species of plants. Because plants adapt so well to almost any climate, scientists needed a way to organize the hundreds of thousands of species. In the same way there is a system of classification for animals, there is also a system of classification for plants. There are two big biochemical processes on Earth: Photosynthesis and Respiration. Plants also have cell walls that are made of cellulose. Not only do you see plants everywhere in the real world, but they are also all over the scientific world. On a non-scientific level, farmers have been observing plants for thousands of years. National Botanic Garden (US Capitol Video)

Cell Function All cells have a purpose. If they don't do anything productive, they are not needed anymore. In the big picture, a cell's purpose is much more important than acting as small organizational pieces. They had their purpose long before they started working together in groups and building more advanced organisms. When alone, a cell's main purpose is to survive. Even if you were a single cell, you would have a purpose. In the same way that cells survive in different ways; all cells have different types and amounts of organelles. While they might have a purpose, more advanced cells have a difficult time surviving on their own.