Biological Molecules - Session 1

Macromolecules are large molecules made up of smaller things called monomers. There are four main types of macromolecules. These are carbohydrates, lipids, proteins, and nucleic acids. Carbohydrates are sugars that provide energy to cells. Lipids are fats and oils that store energy. Lipids are important for cell structure. Proteins are complex molecules made up of amino acids. Proteins have many important functions in cells, such as helping in chemical reactions and providing structural support. Nucleic acids are molecules that store genetic information.

Carbohydrates are organic molecules made up of simple sugars. They are a major source of energy for living organisms. Carbohydrates are found in many foods, including grains, fruits, vegetables, and dairy products. Carbohydrates can be classified into different types based on the number of simple sugar units they contain. These types are monosaccharides, disaccharides and polysaccharides.

We shall first discuss the monosaccharides. The term mono means one. The term saccharide means sugar. Now we know that monosaccharides are type of carbohydrates that consist of only one sugar unit. Some examples of monosaccharides are glucose, fructose and galactose. Glucose is the most important monosaccharide in the body. It is the primary source of energy for cells. Glucose is found in many foods, including fruits, vegetables, and grains.

Fructose is a monosaccharide found in fruits and honey. It is often used as a sweetener in processed foods and drinks. Galactose is also a monosaccharide. It is found in milk and dairy products. Deoxyribose and ribose are also monosaccharides mainly found in the genetic material.

Disaccharides are type of carbohydrates. As the name indicates, di means two and saccharide means sugar. So disaccharides are the carbohydrates that are made up of two sugar units. We can also say that disaccharides are made up of two monosaccharide units. These two monosaccharides are linked together by a bond. Some examples of disaccharides are sucrose, lactose and maltose. Sucrose is made up of glucose and fructose linked together by a bond.

Lactose is made up of Galactose and Glucose. Maltose is also a disaccharide. Maltose is made up of two units of glucose bonded together. This bond or linkage between two monosaccharides is called glycosidic bond. Glycosidic linkage is created when two molecules, such as sugar molecules or a sugar molecule and another molecule, are joined together by removing a molecule of water. As we can see in Maltose, glycosidic bond is formed between two glucose molecules by the removal of a water molecule.

Polysaccharides are complex carbohydrates that are composed of many monosaccharide units joined together by glycosidic bonds. Some examples of polysaccharides include starch, glycogen and cellulose. Starch is found in plants. It serves as a storage form of glucose. Glycogen is a polysaccharide found in animals. It also serves as a storage form of glucose. Cellulose is a polysaccharide found in plant cell walls that provides structural support.

Monomers are small molecules that can join together to form larger molecules called polymers. The word monomer comes from the Greek words mono which means one, and meros which means part. A monomer is a repeating unit of large molecule. These repeating units join together to form polymer. The word polymer comes from the Greek words poly, which means many and meros, which means part.

Cellulose is a polysaccharide. It is a polymer. It is made up of repeating units of glucose. These repeating units join with each other through glycosidic linkage. Cellulose is found in plant cell walls. It provides structural support to the cell wall.

Reducing sugars are a type of carbohydrate that have the ability to reduce other substances by donating electrons to them. This reduction ability is due to the presence of a free aldehyde -COH or ketone -CO- functional group in the sugar molecule. Examples of reducing sugars include glucose, fructose, lactose, maltose, and some forms of starch.

Non-reducing sugars are a type of carbohydrate that cannot be easily oxidized or reduced. They are composed of monosaccharides or disaccharides that do not have a free aldehyde or ketone functional group. This means that they cannot undergo the same chemical reactions as reducing sugars. Examples of non-reducing sugars include sucrose and lactose.

The Benedict's test is a laboratory test used to check if there are particular types of sugars. These sugars are called reducing sugars in a sample. To do the test, we mix a small amount of the sample with a solution called Benedict's reagent. Then we heat it up. If the sample contains reducing sugars, it will change the colour of the solution to a reddish orange colour. The stronger the colour change, the more reducing sugars are in the sample. The test is often used to detect sugars in food or to check for diabetes in urine.