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 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 > triglycerideEmulsion 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.Carbohydrates are used as material for energy storage and production. Starch and glycogen are stored carbohydrates in plants and animals, from which glucose can be used for energy production. 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. Proteins are used to make hormones, enzymes and other body chemicals. It is a building block for cartilage, bones, skin, blood and muscles 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. 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.