Molecular Biology

- Overview

Molecular biology is a branch of biology that studies the molecular basis of biological activity in and between cells. It focuses on the composition, structure, and interactions of cellular molecules, such as nucleic acids and proteins. 

Molecular biology studies how molecules interact with one another in living organisms to perform the functions of life. It focuses on the subcellular level and is commonly used to study regulation and coordination of DNA, RNA, and proteins. 

Molecular biology is a subset of biology that frequently overlaps biochemistry, biophysics, and bioinformatics. 

Some areas of molecular biology include: 

• Biochemistry
• Biophysics and structural biology
• Cell biology, development, and cancer
• Genetics and genomics
• Microbiology, virology, and immunology
• Quantitative and computational biology

- Molecular Biology

Molecular biology is a branch of science that considers the nature and structure of living organisms at the molecular level. Scientists who study molecular biology look at the interactions between various systems of the cell, including the DNA, RNA and the process of protein synthesis. Cell biology, meanwhile, is typically more focused on the structure and functions at the cellular level, and not necessarily the genetic impact on the larger organism. 

Molecular biology is the study of life at the level of atoms and molecules. Suppose, for example, that one wishes to understand as much as possible about an earthworm. At one level, it is possible to describe the obvious characteristics of the worm, including its size, shape, color, weight, the foods it eats, and the way it reproduces. 

Long ago, however, biologists discovered that a more basic understanding of any organism could be obtained by studying the cells of which that organism is made. They could identify the structures of which cells are made, the way cells change, the substances needed by the cell to survive, products made by the cell, and other cellular characteristics. 

Molecular biology takes this analysis of life one step further. It attempts to study the molecules of which living organisms are made in much the same way that chemists study any other kind of molecule. 

For example, they try to find out the chemical structure of these molecules and the way this structure changes during various life processes, such as reproduction and growth. In their research, molecular biologists make use of ideas and tools from many different sciences, including chemistry, biology, and physics. 

- The Central Dogma of Molecular Biology

The key principle that dominates molecular biology is known as the Central Dogma. (A dogma is an established belief.) The Central Dogma is based on two facts. 

The first fact is that the key players in the way any cell operates are proteins. Proteins are very large, complex molecules made of smaller units known as amino acids. A typical protein might consist, as an example, of a few thousand amino acid molecules joined to each other end-to-end. Proteins play a host of roles in cells. 

They are the building blocks from which cell structures are made; they act as hormones (chemical messengers) that deliver messages from one part of a cell to another or from one cell to another cell; and they act as enzymes, compounds that speed up the rate at which chemical reactions take place in cells.

The second basic fact is that proteins are constructed in cells based on master plans stored in molecules known as deoxyribonucleic acids (DNA) present in the nuclei of cells. DNA molecules consist of very long chains of units known as nucleotides joined to each other end-to-end. The sequence in which nucleotides are arranged act as a kind of code that tells a cell what proteins to make and how to make them.
  

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