Human body is mainly made up of 60% water, 5% carbohydrates and 17% fat and more. Protein comprises a similar proportion of the body as fat at 17% and forms essential body components of all the body tissues structure such as cell membranes and genetic material and plays a major role in metabolic systems in the form of antibodies, blood hormones and enzymes. Proteins are used in the body as membranes, like glycoproteins. Moreover it has four levels of the structure which are: primary, secondary, tertiary and Quaternary.Primary structure- The amino acid monomers can be joined together by polymerisation process. This results in chain of hundreds of amino acids joined together called polypeptide chain. The sequence of amino acids in a polypeptide chain forms the primary structure of proteins. Primary structure, is simply the sequence of amino acids in a polypeptide chain. The primary structure of a protein determines its shape and its function. A change in a single sequence of the amino acid can change the shape of the protein and may stop it from carrying its function. Secondary structure- the polypeptide chains can be twisted into different 3D shapes, such as the coil which is the secondary structure of proteins. The secondary structure is held together by hydrogen bonds giving it stability. Two example of secondary structures are alpha helices and beta pleated sheets. The alpha helix is a polypeptide chain that is rod-shaped and coiled in a spring-like structure, held by hydrogen bonds.However beta pleated sheets are made of beta strands these are connected laterally by two or more hydrogen bonds forming a backbone. Each beta strand, or chain, is made of 3 to 10 amino acid residues. Secondary structure, folded structures that form within a polypeptide due to interactions between atoms of the backbone. (The backbone just refers to the polypeptide chain)Tertiary structure- the secondary structure of the protein can be folded and twisted even more to give a specific 3-D shape of each protein. This structure is called tertiary structure of the protein. A number of different bonds maintain this structure. Where the bond occur depends on the primary structure of the protein. The bonds that maintains this structure are;Disulphide bridges, which are fairly strong and it is really hard to break these bonds.Ionic bonds, which are formed between the carboxyl and amino acids. They are weaker than disulphide bonds so are easily broken by changes in the pH Hydrogen bonds, which are easily broken. tertiary structure, primarily due to interactions between the R groups of the amino acids that make up the protein. There are two types of tertiary structure protein: Globular: globular proteins tend to form a ball-like structure in which the hydrophobic part is towards the centre and hydrophilic part face towards edges. The structure the globular proteins makes it soluble in water. Examples of this type of proteins are; antibodies in mammals, enzymes in all organisms and plasma proteins. Fibrous: fibrous proteins tend to form long fibres. These proteins have structural roles for example; keratin in fingernails and hair, and collagen in bone and cartilage. fibrous proteins are insoluble in water as they mostly consists of repeated sequences of amino acids. Ib.bioninja.com.au. (2017). Fibrous vs Globular Proteins | BioNinja. online Available at: http://ib.bioninja.com.au/standard-level/topic-2-molecular-biology/24-proteins/fibrous-vs-globular-protein.html Accessed 15 Nov. 2017.Quaternary structure- Large proteins forms complex structure which contains many polypeptide chains linked together in various ways. The arrangement of multiple folded protein subunits in a multi-subunit complex is the quaternary structure of protein. Examples of protein with quaternary structure include DNA and haemoglobin. https://www.ebi.ac.uk/training/online/course/biomacromolecular-structures-introduction-ebi-reso/proteins/levels-protein-structure https://www.google.co.uk/search?q=protein+4+levels+of+structure&safe=active&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj8nMrV3rvXAhWEKewKHUiTDDIQ_AUICigB&biw=1920&bih=974&surl=1#imgrc=6LvXIVzVziGsbM:Quaternary structure are formed when a charged of a molecule with polar covalent bonds forms an electrostatic interaction with a substance of the opposite charge. The folded parts within the structure are holded by Van der Waal’s forces. The sulphur bridges are formed between two cysteine side chain that end up next to each other due to folded peptide chain. Lysine is an example of a protein that uses ionic bond. Ionic bonds are very strong intramolecular forces. Lysine is use in the treatment of herpes and also increase the absorption of calcium in our body.Threonine includes hydrogen bonding and play an important role in fat metabolism. It prevents the accumulation of fat in the liver and is very useful with indigestion and intestinal disorder.Methionine is is highly hydrophobic protein with sulphur bonded amino acid. Its play in essential role in prevention of deposition of fat in the liver and, also have fat dissolving effect in the body.Biuret testThis test is used for determining if there is a presence of any bond which are peptides. Another common use for it is to measure the concentration of proteins. The biuret test includes these three substances hydrated copper sulphate, potassium hydroxides and potassium sodium tartrate. To do this test you take these steps:Add 2cm3 of the biuret reagent.Add 5% of potassium hydroxide solution and mix it all together.Add 1% of copper sulphate in 2 drops Repeat the step which has just been done but this time add deionized water. By doing this it will prepare and make it to control however by adding albumin it prepares a positive control.Shake well.Let the mixture stand for 5 minutes.Observe the colour change. If you observe a colour change to purple it shows that proteins are present. However if the colour changes to blue it means proteins are not present. Van der waals forces:This is a term used which defines the attraction of forces which are intermolecular between molecules. These are issued from interaction or transient electric dipolar occasions http://slideplayer.com/slide/5872657/Nucleic acidNucleic acids are large biomolecules that are essential to all known forms of life. They allow organisms to transfer genetic informations from one generation to the next. Nucleic acids are composed of nucleotide monomers linked together. Nucleotides are made of three components: a 5-carbon sugar, a phosphate group and a nitrogenous base. There are two type of nucleic acids; ribonucleic acid (RNA) and deoxyribonucleic acid (DNA). Polynucleotide chains are formed when nucleotides are linked together by covalent bonds between the phosphate of one and the sugar of another. These linkages form the sugar phosphate backbone of both RNA and DNA and are known as phosphodiester linkages. The nucleotide structure is shown below;A polynucleotide is composed of 13 or more nucleotides monomers covalently bonded in a chain. The covalent bonds are between the phosphate group of one nucleotide and the third carbon atom of the pentose sugar in the other nucleotide.DNA and RNA are structurally nearly identical. There are three differences in the structure of RNA which makes their function very different from that of DNA. The three differences are: RNA has ribose sugar instead of deoxyribose sugar like in DNA. RNA has uracil instead of thymine.DNA is double stranded whereas RNA is mostly single stranded. The two strands of DNA are coiled together to form a double helix. There are cross-links between the complementary base pairs. importance of nucleic acids:Nucleic acids store information that is used for proteins. The DNA stores genetic information that is needed by the cells to function and RNA is used to convert the information from DNA into proteins. Proteins are used to make hormones, enzymes and other body chemicals. It is a building block for cartilage, bones, skin, blood and muscles. Role of enzyme in metabolism:Each enzyme only promote one type of reaction. Some enzymes break down large nutrient molecules into smaller molecules. They break down nutrients such as fats, proteins, carbohydrates during digestion in the stomach. Other enzymes guide these smaller molecules through the intestinal wall into the bloodstream. There are some enzymes that promote the formation of large molecules from the smaller ones. Enzymes are also responsible for some other functions in the body such as, release and storage of energy, the process of respiration, the course of reproduction.Antibody:An antibody also known as immunoglobulin is a Y-shaped protein that is produced by plasma cells. These plasma cells are used by the immune system. The antibody recognizes an antigen which is a unique molecule of the pathogen. Hormones;Hormones are chemical secreted by the glands to help regulate the processes in the body. They are targeted for different organs. The hormones are transported from the gland to the targeted organ through the bloodstream. Dopamine is produced in a lot of areas of the brain, including even the substantia nigra and the ventral tegmental area. It is a neurohormone that is released by the hypothalamus. It’s action is as a hormone that is an inhibitor or prolactin release from the anterior lobe of the pituitary. Hormones are chemical substances that help to regulate processes in the body. Insulin is one such hormone, regulating the level of glucose in the blood.Lipids Lipids also known as fats have many functions in the body. They provide energy to main body homeostasis and also to produce hormones. Lipids is needed to maintain the body healthy as we cannot digest or absorb food without them. Lipid contain carbon, hydrogen and oxygen. Lipid are stored in adipose tissue which contributes in a lot of important roles: energy sources-Lipids provide more than twice the amount of energy as carbohydrates – about 38 kJ/g.insulation and organ protection in animals – in mammals, adipose tissue underneath the skin helps reduce heat loss. Insulation prevents evaporation in plants & animals (i.e. waxes)phospholipids in membranes which helps protect the cells – adipose tissue around delicate organs such as the kidneys and heart acts as a cushion against impacts. They also form the myelin sheath around some neuronsAct as ingredient for the production of vitamins and hormones There are three main types of the lipid present. Triglycerides which contains three fatty acid and a glycerol. 3 fatty acid molecules joined to a glycerol fatty acids bond to glycerol by ester bonds formed by condensation reactionsPhospholipid is composed of two fatty acid, a glycerol and a phosphate groupSteroids has four fused ringsEach fatty acid consists of: a carboxylic acid group COOH, a long hydrocarbon chain and a methyl group CH3. Fatty acid can be saturated or unsaturated. Saturated fat is a type of fat in which the fatty acid chains have all single bonds and occur naturally in solid state whereas in unsaturated fat consist of at least one double bond and exist in liquid state. The straight arrangement of hydrocarbon allows them to lie straight and the molecules will pack neatly into a solid arrangement whereas in unsaturated fat missing hydrogen atoms cause kinks in the fatty acids which reduces the amount of intermolecular bonding that can occur and keeps the molecules liquid at room temperature. Monounsaturated is when there is one double bond is present between carbon atom. In polyunsaturated there are more there one double bond are present between carbon atoms.Esterification reaction:For this reaction the word equation is Glycerol+fatty acid > triglyceride https://www.masterorganicchemistry.com/reaction-guide/conversion-of-carboxylic-acids-to-esters-using-acid-and-alcohols-fischer-esterification/Emulsion testTo detect lipids, the emulsion test is used to do this test this is what you have to do:The substances which is the test substances is mixed with the measurement of 2cm3 of ethanol.Then add another 2cm3 distilled water.If a Milky white solution is formed lipid are not present.Cystic fibrosis (CF)Cystic fibrosis is a recessive genetic disorder that affects the movement of salt and water in and out of the cell which leads to the buildup of thick, sticky mucus in the trachea and passageways mainly in the digestive system and the lungs. Cystic fibrosis is a recessive disease which means that for a person to have CF, they need to inherit two faulty CFTR(Cystic fibrosis transmembrane conductance regulator) genes from each of their parents. The person is called a carrier if they have only one defaultly CFTR gene and will exhibit no symptoms of cystic fibrosis. CFTR protein uses energy from nucleotide hydrolysis to transport. Molecule across the membrane. Channel pores allows the transport of Chlorine ions across the membrane which is produced by the transmembrane domains and its makes 19% of CFTR. The opening and closing of the channel cause the domains to links the nucleotide ATP together, due to which ATP is able to join to these domain. The R domain regulates the channel activity by triggering whether the channel opens and closes. CFTR channels can be found in the apical membrane of the epithelial cells. They play an essential role in the transport of fluid and electrolyte by the process called gating. In this process, the channel open and closes in order to transport chlorine and bicarbonate ions out of the epithelial cell. The flow of chlorine out of the cell has huge impact on the ionic balance hydration of secretion in organs.Lactose intoleranceAn individual that is lactose intolerance means that their body is incapable or has trouble consuming lactose or ‘milk sugar’, which is present in cow’s milk, as well as many other dairy products such as cheese. Lactose intolerance does not involve immune system, unlike other food allergy. Lactose intolerance is caused by the shortage of the enzyme called Lactase. Lactase is normally produced by the cells present in the lining of the small intestine. The enzyme lactase breaks down lactose into the glucose and galactose, which is then absorbed into the bloodstream to supply throughout the body. In case of lactose intolerance, person either produce no or insufficient lactase. As a consequence of lactose intolerance, the lactose will be fermented by the bacteria present in the intestine, which leads to the number of complains like flatulence, gastrointestinal complains and diarrhoea.