A unicellular organism is any life form that is composed of a single cell; they live and carry out all life processes as a single cell. Based on their complexity, unicellular organisms can be placed in one of two categories: eukaryote and prokaryote. Most unicellular organisms are microscopic, but some are visible to the naked eye.
Eukaryotes have a simple cell structure compared to prokaryotes. The prokaryotic unicellular organism does not have a cell nucleus, while the eukaryotic unicellular organism has a nucleus within the cell. The evolution theory suggests that unicellular organisms were the first living things on earth, existing approximately 3.8 billion years ago.
Unicellular organisms pursue different strategies for survival, including heterotrophy (amoeba), chemotrophy and photosynthesis (cyanobacteria). Unicellular organisms include most life on earth and can be found in virtually every habitat, including the least hospitable conditions. Common examples of unicellular organisms include: cyanobacteria, bacteria, paramecium and amoeba. Most single-celled organisms live in colonies, but each organism remains self-sufficient.
The opposite of a unicellular organism is a multicellular organism. Multicellular organisms are typically larger and require specialized organ systems. They require complex organ systems to facilitate communication between cells, control exchanges with the external environment and supply the cells with the required nutrients.Learn More
Lipids are a wide category of compounds that are known as biomolecules. Lipids include neutral fats, steroids, oils and waxes. They are created by the body naturally to be used in a variety of biological membranes and reactions.Full Answer >
Physical digestion is the physical process of breaking down food into smaller pieces that can easily be accessed by digestive enzymes, without making any chemical changes, whereas chemical digestion refers to the process through which the mammalian body further breaks down food substances into small, soluble chemicals that can be absorbed into the blood. The chewing of food and movement in the stomach contribute to physical digestion while natural catalysts aid chemical digestion.Full Answer >
A multicelled, or multicellular, organism is any living being comprised of more than one cell. Typically, multicellular life differentiates cells into specialized tasks, which in larger organisms can form tissues and organs. This allows multicellular organisms to have cells that are more efficient at a specific function of life.Full Answer >
The hamstring tendon attaches the hamstring muscle to an area just below the knee joint known as the tibia. It assists with hamstring muscle and aids in bending the knee. The hamstring muscle is located at the back of the thigh and stretches from the pelvis to the knee joint.Full Answer >