If this is the first time we've heard about antibodies, you may not know how important they are. Antibodies are one of the warriors inside our body helping us fight of nasty invading particles. They are a type of protein and a key component of our immune system. If a person doesn't produce or overproduces antibodies in the body, the person will become very ill. Another way to antibodies come from. Antibodies circulate in the bloodstream and can appear anywhere throughout the body. The function is to recognize bad agents called antigens and then trigger further chemical reactions in the body to remove the antigens. Antigens are foreign substances that are capable of triggering an immune response. They can be viruses, fungi, bacteria and some non-living substances such as toxins, chemicals and foreign particles. They can even be allergens like dust, pollen or certain foods that cause allergic reactions. Antibodies are produced in the immune system in response to the presence of an antigen. So what do antibodies look like? Antibodies are also known as immunoglobulin. They are generally a wide-shaped protein consisting of four polypeptides, two identical light chains and two identical heavy chains. The terms light and heavy simply mean larger and smaller. The four polypeptine chains are connected by disulfide bridges. Here, at the top of each arm are the antigen binding sites. These are really important parts for attacking and invading antigens. Similar to the locking key mechanism in enzymes, the shape of the antigen binding site is specific to the antigen it's targeting. If part of the antigen fits into the antigen binding site, the antivari recognizes the foreign antigen and bind it in. This stops the antigen from causing more damage elsewhere. Two identical binding site means any given antivari can bind simultaneously to two identical antigens. Millions of antivari will slightly different top structures exist, with each variant binding to a different antigen. This enormous diversity of antivari allows the immune system to recognize and equally diverse range of antigens. By binding in an antigen, an antivari can stop the antigen from entering or damaging cells. This is known as mutualizing. The antivari can also take the antigen for attack by other parts of the immune system. In mammals, they are five immunoglobulin isotopes. They perform direct diorls and help directly appropriate immune response for each different type of foreign invader. Antibodies are cloned in laboratories to discover how and why watch this video. So there we have the ninja-wise shaped antibodies protecting us from foreign invading antigens. It's unyeli-identical, except for slightly different shaped antigen binding sites.