 A polymer is a macromolecule, or a large molecule made of many repeating monomer subunits. We can think of the monomers as beads. Link them up to form a necklace, the polymer. Let's have a look at this potato plant right here. Notice how it is standing upright without any support. This is due to a polymer known as cellulose. To be correct, this is a polysaccharide. A polymer made of many repeating sugar, or specifically glucose subunits. Now layer all these polymers that you have formed. It is an even stronger structure. Now add more and intertwine them. This is the main component of plant cell walls. So now you can see why the stem of your potato plant can stay upright. Let's now look at the potato itself. It is very starchy. Starch is actually a combination of a myelos and a myelopectin. A myelos is also made of glucose monomers and has a helical structure. A myelopectin, on the other hand, is like a myelos, but has branches of glucose chains. Have a look at that tree in the background. The trunk is very very rigid and strong. It can't just be due to the cellulose, or else the stem of the potato plant would be much stronger. The reason why it is rigid is because the cellulose and other fibers are held intact by another natural polymer called lignin. Here's the challenge for you. Where do we get paper from? Pause, think, and resume the lesson when ready. Paper comes from wood, which come from trees. Paper is in fact made from cellulose. It is just layers of cross-linked cellulose fibers. If you tear a piece of paper and look closely, you will see those fibers. When paper is made, lignin must be separated from cellulose in a process called pulping, or else we would not be able to fold or crumple it. Now let's look at ourselves. So what exactly makes us what we are? DNA, or deoxyribonucleic acid, is a polymer of nucleotides. Each nucleotide is made of a sugar, a nitrogenous base, and two or three phosphate groups. Our DNA is the genetic blueprint of what we are. There are only four nucleic acids that form our DNA, yet the possibilities of arranging these monomers are virtually endless. A section of DNA that codes for a protein is known as gene. Our genes determine whether we have brown or blue eyes, blonde or black hair, straight or curly hair, and even the smaller features, such as your dimples and the shape of the hairline. Genes are necessary to make all the enzymes needed to carry out the reactions in our bodies. Genes are polymers made from amino acid monomers. There are endless types of proteins, each with a unique structure and function. Breathe in. Oxygen is transported through your blood by a protein called hemoglobin, as you inhaled your chest rose. This was made possible by your chest muscles. Your muscles are a collection of muscle cells, which are rich in protein chains or filaments. Feel the top of your ear. The hard yet flexible part is cartilage, which is also a type of protein. This cartilage is also found in joints. It makes it possible to move our arms and legs. Feel the tip of your nose. It is also made of cartilage. Caritin is a fibrous protein, responsible for maintaining the firmness of our skin. As time progresses, the collagen loses its elasticity, just like an overused elastic band, when this happens, grooves in our skin form, otherwise known as wrinkles. Hair and nails are made of keratin, yet another type of protein. Caritin is not exclusive to humans, but is also found in bird feathers, turtle shells, and cat claws. Moving on to other living organisms, silkworms can produce their own silk protein to spin its cocoon. This is still done on a large scale in some countries. However, some people find this unethical, as the larvae inside the cocoon are killed during this process. The exoskeleton, or shells of crustaceans, such as crabs and lobsters, are formed from chitin. Chitin is a polymer made of repeating and acetylglucosamine monomer subunits, whose structure is derived from glucose. Interestingly enough, chitin is also found in the cell walls of fungi, most notably mushrooms. Cell rubber is also a polymer of isoprene monomer subunits. This is found in latex, which is a white milky substance that is tapped from para rubber trees. This can be used to make latex gloves, erasers, elastic bands, adhesive, and balloons, as well as many other useful everyday materials. The rubber in car tires is a vulcanized rubber, meaning that sulfur has been added to introduce cross-linking between the polymers, which strengthens the structure. To summarize, there are many natural polymers, each with their own specific structure and function.