Testing for the Presence of Carbohydrates, Proteins and Lipids

Cell membranes have a series of properties that contribute to the presence of lipids and proteins. The structure is very similar. They consist of lipids, proteins and carbohydrates. Membranes are amphiphilic (including hydrophobic and hydrophilic regions). Each protein enables the function of the membrane. Maintain the membrane with a weak noncovalent bond. Asymmetry of structure High fluidity. The membrane is polarized. The presence of lipids in cell membrane structures is important because cells specifically influence their fluidity. As described in the next section, this is necessary to allow things to enter and leave the cell. One factor that plays an important role in this regard is cholesterol as shown below. Another is the presence of double bonds. The more double bonds, the greater the amount of twist or curve in the lipid, thus increasing the free space. Lipid length also works

Carbohydrates attach to membrane lipids and proteins as short oligosaccharide chains. Proteins bound to sugar molecules are called glycoproteins, and lipids attached to sugar molecules are called glycolipids. Carbohydrates form a pericellular protective shell called sugar coating, which helps to recognize cells. Glycoproteins are formed by glycosylation of proteins. There are two types: N-glycosylation (sugar linkage to the nitrogen atom of the asparagine residue) and O-glycosylation (the sugar is attached to the hydroxyl group of the serine or threonine residue). Examples of glycoproteins found in the body are mucin, collagen, transferrin, immunoproteins and others.

Food science includes three biological elements of food - carbohydrates, lipids, proteins -. Carbohydrates are sugars and starches which are the chemical fuels necessary for our cells to operate. Lipids are fats and oils, an important part of the cell membrane that smooths and buffs the internal organs. Since fat has more than 25 times more energy per gram of carbohydrates and protein, many people try to limit intake to avoid overweight. Proteins are complex molecules composed of 100 to 500 or more amino acids that bind to each other and are folded into the three-dimensional shape necessary for the structure and function of each cell. Our body can synthesize several amino acids; however, 8 essential amino acids must be taken as part of our food. Food scientists are also interested in inorganic ingredients in foods such as moisture, minerals, vitamins, and enzymes.