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Molecules of Life

You can read your protein You can read your protein Proteomics is the large−scale study of proteins, particularly their structures and functions. This relies on genome (complete set of genes) and proteome (entire set of proteins expressed by an organism) information to identify proteins associated with a disease with the help of computer software. If a certain protein is implicated in a disease, its 3D structure provides the information to design drugs to interfere with the action of the protein. Life's large biomolecules are the main subject of this chapter. Let's learn more about the biomolecules that helps to understand the recent advances in biomolecular engineering like proteomics.

Learning Objectives

After completing the topic, the student will be able to:

  • Predict and analyze how small organic molecules are joined inside cells, forming larger molecules called macromolecules.
  • Discover how carbohydrates serve as fuel and building material for molecules.
  • Define and distinguish the structures and functions of fats, phospholipids, and steroids.
  • Discriminate the structural concepts of saturated and unsaturated fatty acids and how they affect our health.
  • Explore the structure and functions of proteins in cells and summarize the concept of how a polypeptide is constructed from amino acids.
  • Analyze the factors that affect protein structure and functions and evaluate how enzymes act as biological catalysts.
  • Deduce how nucleic acids store and transmit hereditary information.
Molecules of life Molecules of Life Molecules of life are classified as - carbohydrates, Lipids, proteins and nucleic Acids. 20 to 25 percent of living matter consist of these macromolecules.
Biological molecules

Water, inorganic ions and a large array of relatively small organic molecules (e.g. sugars, vitamins, fatty acids) account for 75−80 percent of living matter by weight. Of these small molecules, water is by far the most abundant. Each type of small molecule has unique properties arising from the orderly arrangement of its atoms. Small organic molecules are joined inside cells, forming larger molecules called macromolecules.

The four main classes of large biological molecules are carbohydrates, lipids, proteins and nucleic acids. 20−25 percent of living matter consists of macromolecules, including proteins, polysaccharides and DNA. Though all of these groups are organized around carbon, each group has its own special structure and function. Cells acquire and use these macromolecules in fundamentally different ways.

Ions, water and many small organic molecules are imported into the cell. Cells also make and alter many small organic molecules by a series of different chemical reactions. In contrast, cells can obtain macromolecules only by making them. Their synthesis entails linking together a specific set of small molecules (monomers) to form polymers through repetition of a single type of chemical−linkage reaction.

Nucleotides Nucleotides act as precursor for nucleic acids Biopolymers such as nucleic acids, proteins, and polysaccharides (such as starch or cellulose) are made up of small molecules.
Examples of macromolecules

Some small molecules function as precursors for synthesis of macromolecules, and the cell is careful to provide the appropriate mix of small molecules needed. Small molecules also store and distribute the energy for all cellular processes; they are broken down to extract this chemical energy, as when sugar is degraded to carbon dioxide and water with the release of the energy bound up in the molecule.

Other small molecules (e.g., hormones and growth factors) act as signals that direct the activities of cells, like nerve cells communicating with one another by releasing and sensing certain small signaling molecules.

The powerful reaction/response of our body after a frightening event comes from the instantaneous flooding of the body with a small molecule hormone that mobilizes the "fight or flight" response.

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