Question

What are the four classes of biologically important macromolecules and explain how they contribute to cell structure and function

Answer 1

The major types of biologically important macromolecules are carbohydrates, proteins, lipids and nucleic acids.

Carbohydrates are, in fact, an essential components of our diet. Grains, fruits, and vegetables are all natural sources of carbohydrates. These are compounds made up of carbon, Hydrogen and Oxygen. Starch, Glycogen cellulose etc are examples of carbohydrates. These are polysaccharides made up of several monosaccharides. These polysaccharides are made up of many glucose (monosaccharide) units. Glucose, frutose, ribose, galactose etc. are examples of monosaccharides. Carbohydrates are important source of energy. Carbohydrtes are oxidized with the help of enzymes in the body for releasing energy. Inside the body carbohydrates can be converted into, fats, amino acids and it is also a component of nucleic acids. Glycogen is a polysaccharide that can be stored in the body for meeting future energy demands of the body.

Proteins are polymers made up of amino acids. Proteins are components of the plasma membrane and all intracellular membrane structures. Proteins also function as enzymes, hormones, receptors, signalling molecules, neurotransmitters etc. Proteins can be oxidized in the body with the help of enzymes for producing energy.

Lipids are molecules that contain Carbon, Hydrogen and Oxygen. Examples of lipids include fats, oils and waxes. Lipids are important components of cell membranes and thus have a structural role. LIpids can be stored in the body. Enzymatic oxidation of lipids inside the body produces energy. They also function as hormones, signalling molecules etc.

Nucleic acids are made up of Carbon, Hydrogen, Oxygen, Nitrogen and Phosphrous. Nucleic acids like DNA and RNA are functioning as genetic material. DNA is the genetic material of all organisms ranging from bacteria to human beings. RNA is the genetic material of some RNA viruses. In a eukaryotic cell DNA is found mostly in the nucleus in the chromosomes. RNA is found both in the cytoplasm and nucleoplasm. Certain RNAs also funtion as enzymes. RNA enzymes are called ribozymes.