Proteins are everywhere. As enzymes, they catalyse chemical reactions. There are many different types of proteins: carrier and channel proteins which transport substances, receptor proteins which are recognition site for antibodies and hormones, structural proteins which support cells and tissues, and hormones which transmit information.
Proteins are big molecules with large molecular masses that are made up of many amino acids; they’re, essentially, polymers of amino acids. There are only about 20 different types of amino acids but they make up millions of proteins. There are four elements that make up amino acids: carbon, oxygen, hydrogen and nitrogen. However, some amino acids such as …show more content…
The primary structure of haemoglobin is important because a change in only one amino acid can disrupt haemoglobin's function. For example, a single amino acid change to haemoglobin's primary structure can cause sickle cell anaemia, a blood condition characterized by dysfunctional, sickle-shaped red blood cells.
Dystrophin is another protein with an important primary structure. The presence of dystrophin contributes to muscle functioning, and the protein helps maintain the structure of your muscle fibres. Genetic mutations that change the primary structure of dystrophin, such as the substitution of one amino acid for another or deletions of amino acids, can harm your muscle fibres, leading to diseases such as Duchenne muscular dystrophy, where the muscles weaken and begin to waste away. Secondary Structure
The secondary structure is the folding of the amino acid chains into an alpha-helix or a beta-pleated sheet. It is determined by the sequence of amino acids in the primary structure. The polypeptides within the secondary structure are held together by many hydrogen bonds, which give the structure great …show more content…
Disulphide bonds – these are very strong bonds that contribute to the strength of structural proteins such as keratin and collagen. Where two cysteine amino acids are found together, a strong double bond (S=S) is formed between the Sulphur atoms within the Cysteine monomers.
Proteins with a 3D structure fall into two categories: * Globular – these tend to form ball-like structures where hydrophobic parts are towards the centre and hydrophilic are towards the edges, which makes them water soluble. They have a relatively unstable structure and usually have metabolic roles. For example: enzymes in organisms, plasma proteins and antibodies in your body. * Fibrous – these proteins form long fibres and mostly consist of repeated sequences of amino acids which are insoluble in water. They have a stable structure and usually have structural roles, such as: Collagen in bone and cartilage, Keratin in fingernails and hair.
Tertiary structures can be easily broken by heat. Heat increases the kinetic energy of the particles, meaning that they will vibrate more and the bonds will be more likely to break apart. When a protein loses its shape like this, it