Molecular biology
Molecular biology is the discipline that investigates the structure and function of biological molecules in living organisms. By examining individual molecules in plants and animals, scientists can better understand the mechanisms underlying health, disease, and biological processes. The foundations of molecular biology were laid in the seventeenth century by pioneers such as Antonie van Leeuwenhoek, who was the first to observe microorganisms and blood cells using a microscope, and Robert Hooke, who studied plant cells. These early discoveries highlighted the importance of microscopic observation in understanding life at a molecular level.
At the core of molecular biology are atoms and molecules, which combine to form cells—the fundamental units of life. The relationships among different types of molecules, particularly the four major macromolecules (lipids, proteins, carbohydrates, and nucleic acids), are crucial to understanding cellular functions. For instance, nucleic acids like DNA and RNA are essential for genetic information, while proteins play vital roles in processes such as metabolism and cell signaling. By exploring the interactions and functions of these molecules, researchers can gain insights into the complexities of living systems and their underlying biochemistry.
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Molecular biology
Molecular biology is the study of living organisms at the molecular level. Understanding the structure and functions of individual molecules in both plants and animals allows scientists to keep people healthier and protect them against disease and illness. Thanks to discoveries made in the seventeenth century, it became known that microbes are capable of spreading disease and that blood contains oxygen-carrying proteins called “hemoglobin.”
On a molecular level, all organisms look the same. Everything, from a person to a lizard and a tree, carries similar atoms, molecules, and cells. However, high-powered electron microscopes are required to study an organism’s molecular structure. Without understanding how organisms operate on a molecular level, it would be difficult for scientists to understand how they function on a cellular level.
Brief History
In 1674, Antonie van Leeuwenhoek (1632–1723) changed the way people viewed molecular biology. To his surprise, when he took a drop of lake water and looked at it under a microscope, Leeuwenhoek noticed small “creatures” swimming around in the drop. Following this discovery, he went on to become the first scientist to view blood cells, bacteria, protozoa, and sperm cells at a microscopic level. Although Robert Hooke (1635–1703) observed plant cells for the very first time in the 1660s, Leeuwenhoek is credited as having laid the foundation for modern-day molecular biology.
After studying plant cells in the latter half of the seventeenth century, Hooke published his observations and drawings in the book Micrographia (1665). In it Hooke mentions a variety of topics, including the molecular characteristics of fire and even the anatomy of insects. This sparked a trend that helped more scientists make discoveries using microscopes. Everything that scientists know today about molecular biology stems from the early discoveries made by these two scientists in the seventeenth century.
Overview
In order to understand living things, it is important to first understand how molecules work. Cells, the basic building blocks for life, are arrangements of many molecules bonded together through chemical means. If every organism on earth were broken down to their most basic form, one would see the same basic components: atoms of different elements bonded together to create the molecules needed for life to thrive.
An atom is the smallest unit of matter that can exist on its own, much smaller than a cell. More than one hundred types of atoms are known, in the forms of each element on the periodic table, such as the element gold (Ag). An element is a form of matter consisting only of atoms with the same the number of protons (a positively charged subatomic particle) in the nucleus. Whenever several atoms stick together through chemical bonding, a molecule is formed. Both atoms and molecules are directly responsible for the existence of cells, and therefore, the existence of life. In molecular biology, the basic structure of life proceeds as follows: organisms are composed of cells, cells are composed of molecules, molecules are composed of atoms, and finally, atoms are composed of subatomic particles including protons, neutrons, and electrons.
Another example of how atoms can give rise to a molecule is the nucleotide, the basic building block for DNA. All nucleotides contain a phosphate group (PO4), comprising four oxygen atoms (O) bonded to a single phosphorus atom (P). Building from there, phosphate is a molecule responsible for adding support and structure to DNA molecules, which in turn, help cells to function properly. Individual atoms bond together and create molecules for stability. Atoms of certain, but not all, elements are not very stable on their own. They bond with atoms of different elements in order to have a more stable structure. One of the most reactive elements on the periodic table is hydrogen (H). Due to their elemental structure, individual hydrogen atoms will bond with just about any other element on the periodic table. On the other hand, neon (Ne) is an element that does not need to bond with other elements in order to have a stable structure.
The basic drive for atoms of different elements to bond together is what gives rise to molecules. In general, it takes many molecules to build a single cell, and it takes trillions of cells to build a human body. Among the most common types of molecules found in humans are the four major macromolecules: lipids (fats), proteins (amino acids), carbohydrates (sugars), and nucleic acids (DNA and RNA). The basis of molecular biology revolves around these four types of molecules. For instance, lipids are the molecules responsible for storing energy in living organisms, while carbohydrates are more of an active energy source. Nucleic acids give rise to DNA and RNA, the blueprints for life, while proteins are the molecules responsible for such essential life functions as cell signaling and metabolism. By understanding how life functions on a molecular level, scientists gain a better understanding about what to expect on a cellular level.
Bibliography
Berg, Jeremy M., John L. Tymoczko, and Lubert Stryer. Biochemistry. 7th ed. New York: Freeman, 2011. Print.
Bhagavan, N. V., and Chung-Eun Ha. Essentials of Medical Biochemistry: with Clinical Cases. Amsterdam: Elsevier/Academic, 2011. Print.
Bhardwaj, Uma, and Ravindra Bhardwaj. Biochemistry for Nurses. New Delhi: Dorling Kindersley/Pearson, 2012. Print.
Fromm, Herbert J., and Mark S. Hargrove. Essentials of Biochemistry. Berlin: Springer, 2012. Print.
Lodish, Harvey, et al. Molecular Cell Biology. 7th ed. New York: Freeman, 2013. Print.
"Molecular Biology." Stanford Encyclopedia of Philosophy, 20 Feb. 2024, plato.stanford.edu/entries/molecular-biology/. Accessed 13 Nov. 2024.
Newsholme, Eric Arthur, Tony Leech, and Mary Board. Functional Biochemistry in Health and Disease. Chichester: Wiley-Blackwell, 2009. Print.
Pollard, Thomas D., and William C. Earnshaw. Cell Biology. 2nd ed. Philadelphia: Saunders/Elsevier, 2008. Print.
Rogers, Kara. The Cell. New York: Britannica, 2011. Print.
Sichamba, Patson, et. al. "A Retrospective Analysis of Wastewater Confirms Dominant Circulation of SARS-CoV-2 Delta Variant in Nairobi, Kenya, between April 2021 and August 2021." American Journal of Molecular Biology, vol. 12, no. 3, July 2022, doi.org/10.4236/ajmb.2022.123010. Accessed 28 Dec. 2022.
Varki, Ajit. Essentials of Glycobiology. Cold Spring Harbor: Cold Spring Harbor Lab, 2009. Print.