Lignin
Cellulose is the structural protein in plants.
proteins in plants are mainly enzymes and structural molecules. Cellulose is not a protein, but chloroplasts contain proteins. Hope this helps!
Collagen is a structural protein found in the body, giving strength and support to tissues such as skin, bones, and connective tissues.
It a structural protein
Enzymes are proteins, as too are many structural parts of plants, and even organelles within cells are composed of protein. Nuts and seeds always contain large amounts of protein, as they need to support the plant in its first few days of 'life'.
Structural Protein
Sequencing a protein to discover the sequence of amino acids is an example of structural analysis. Understanding how that protein functions and interacts with other proteins in a cell is an example of functional analysis.
Lignin is not a protein but it the "cement" that binds cellulose together to give plants and trees its structural strength. Lignin offers rigidity (so trees have more lignin than plants) whereas cellulose offers load bearing capability (like iron rods in reinforced concrete). The equivalent of lignin in animals is collagen, which is a protein. An interesting fact linking these two structural support molecules, lignin in plants, and collagen in animals, is that both the biomolecules require oxygen for their synthesis. So nature could have only created multicellular organisms with structure after oxygen became abundant on earth. The abundance of oxygen itself was triggered by single cell bacteria that "excreted" oxygen when they made food from sunlight. So nature "bootstrapped" larger living creatures using the excretion of single cell life.
yes it is.
Hemoglobin - formed with alpha helices and/or beta sheets, but as one, contiguous polypeptide. Superoxide dismutase would be a good example of a quaternary structure protein, since it is made of more than one polypeptide chain.
Keratin.
No it is not a hormone. It is a structural protein