Microbiology is the study of microbes - organisms too small to be seen by the naked eye.
Microorganisms are found in a wide range of habitats from hot springs to polar regions, to the depths of the ocean. These organisms which include bacteria, algae, protozoa and fungi live in association with plants and animals. Virology is a branch of microbiology which includes the study of viruses and virus-like agents: submicroscopic entities that can only survive inside a cell. These hosts include bacteria, plants, animals and humans. Because viruses must take over a cell in order to reproduce, they often interfere with gene expression and cell growth, leading to cancer formation and its spread.
First and foremost, microbiologists need to find out about the detailed workings of microbial cells before they can use this basic knowledge in applied microbiology to solve problems caused by microbes or to exploit their useful features.
The main function of the immune system is to protect us against microorganisms found in our hostile environment. While these defense mechanisms are instrumental to our health, excessive, or undesired activation of the immune system is encountered in allergic reactions, autoimmune (self-destructive) disorders and transplant rejection. Immunology is the study of how our defense mechanisms serve to eliminate disease-causing microbes and tumour cells, how harmful immune responses are developed, how useful responses can be boosted and how harmful responses can be avoided.
Immunologists try to understand how immune responses are developed in health and disease and how these responses can be boosted to better protect us against threats posed to our health from outside (i.e., pathogenic viruses) or from within (i.e., spontaneously arising cancer cells).
Microbiology and Immunology graduates have the background for careers in a variety of specialized areas.