Biological Molecules

Overview of Biological Molecules

  • Biological molecules are complex substances vital for life; they are built up from simple units by living organisms.
  • The four main types of biological molecules are carbohydrates, lipids, proteins, and nucleic acids.
  • These molecules serve numerous critical functions ranging from providing structure and energy to controlling metabolic processes.

Carbohydrates

  • Carbohydrates are molecules composed of carbon, hydrogen, and oxygen atoms.
  • They function mainly as a source of energy and for short-term energy storage.
  • Simple unbranched chains of sugar molecules form starches, while branched chains make glycogen.
  • Cellulose, another type of carbohydrate, is used by plants to build their cell walls.

Lipids

  • Lipids are biological molecules that include fats, steroids and phospholipids, which are insoluble in water, but soluble in organic solvents.
  • They are a critical component of cell membranes and are used by organisms for long-term energy storage.
  • Animal and plant cells store lipids as fat for insulation and cushioning.

Proteins

  • Protein molecules are made up of one or more chains of amino acids.
  • They are known for their role in cell structure, function, and regulation.
  • Enzymes, a type of protein, are responsible for speeding up biochemical reactions in living organisms.

Nucleic Acids

  • Nucleic acids, including DNA and RNA, are responsible for storing, transmitting, and expressing genetic information.
  • DNA (deoxyribonucleic acid) holds the genetic blueprint for each living organism.
  • RNA (ribonucleic acid) aids in the process of using DNA to create proteins and plays a role in protein synthesis.

Roles of Biological Molecules in Food and Ecosystems

  • Digestive processes break down consumed foods into smaller molecules that can be absorbed and used by cells.
  • Biological molecules also form the basis of food webs, as they pass along a food chain from one organism to another.
  • For example, plant carbohydrates, consumed by herbivores, are broken down and transformed into proteins and other substances in the consumer’s body. These nutrients are then passed up the food chain to carnivores and omnivores.
  • Understanding the role and function of biological molecules aids in a holistic understanding of biological ecosystems.