Oxygen-Carrying Protein in the Blood: Hemoglobin. Hemoglobin is the protein that transports oxygen (O 2) in human blood from the lungs to the tissues of the body. Proteins are formed by the linking of amino acids into polypeptide chains.n hemoglobin, each subunit contains a heme group, which is displayed using the ball-and-stick representation in Figure 2. Each heme group contains an iron atom that is able to bind to one oxygen (O 2) molecule.
Decomposer: is an organism, usually a bacterium or fungus, that breaks down the cells of dead plants and animals into simpler substances. A fungus, such as this mushroom, is a decomposer of dead plants.
The direction of arrows between the organisms shows who eats what. A decomposer means an organism that breaks down large molecules from dead organisms into small molecules and returns important materials to the environment. Sooner or later, all living things die. When a plant or an animal dies, its body begins to break down into small pieces. Special living things called decomposers break down the body. A decomposer makes dead things into chemicals and then the chemicals go into the air, ground or water and is used again. Examples of decomposers are: earthworms, molds, fungus, bacteria, and mushrooms.