What is Microbiology?

Introduction

A microorganism is a unicellular life form that cannot be seen with the naked eye. There are more microorganisms on and inside our body than there are cells that make up our entire body. Microorganisms are also referred to by their shorter name - microbes. Microbiology is a science that studies microorganisms. This chapter discusses the main groups of unicellular organisms. It also looks at the different branches of microbiology.

Microscope

Microbes can only be seen with a microscope. A microscope is an optical instrument used to see objects that are too small to be seen with the naked eye. It is the most important device used by microbiologists. Modern light microscopes are monocular, with on eye piece, or stereo, with two eye pieces. Electron microscopes use a beam of electrons instead of light that is transmitted through the specimen. These microscopes can magnify the object approximately a million times.

Prokaryotes and eukaryotes

All biological cells have following attributes in common:

• DNA - a cell's genetic information carrier. In some cells DNA is in a separate cell structure called the nucleus and in others it just 'floats' in the cell's cytoplasm in the form of the nucleoid;
• Membrane - the outer thin protective layer;
• Cytoplasm - jelly-like matter inside the membrane.

A cell's nucleus is a very important organelle. It controls all processes within the cell. Some cells have a well-defined nucleus and some do not. All cells are divided into two large groups: cells with a nucleus called eukaryotic cells, or simply eukaryotes, and cells without a well-defined nucleus, called prokaryotic cells, or prokaryotes. Microorganisms include both groups.

The table below will help you to better understand differences between prokaryotes and eukaryotes.

Producers and consumers

All organisms need energy to grow and reproduce. Proteins are the main compounds of all cells. They are large molecules made of one or more chains of amino acids. Carbon (C - in the periodic table) occurs in all organic compounds, so all living things need to obtain it from somewhere. Depending on how they obtain it, all organisms are divided into two groups: heterotrophic organisms, or heterotroph, and autotrophic organisms, or autotrophs.

Heterotrophs are organisms that cannot create their own food so they feed on other life forms. Heterotrophic microorganisms include some bacteria, viruses and fungi.

Autotroph means 'self-feeder'. These types of organisms can make their own food (different forms of sugar, proteins and lipids) using the energy of sunlight and carbon dioxide (CO₂) in the process called photosynthesis. Autotrophic microorganims include algae, protozoans and some types of bacteria. Autotrophs are the primary producers in all food chains.

Autotrophs and heterotrophs are also called producers and consumers. See image 3.

Branches of microbiology

Microbes are literally everywhere. They can be found in the air, soil, water, rocks and bodies of other living organisms. That is why microbiologists study not only microorganimsms themselves but also their surroundings and their interaction with these surroundings.

According to the subject of the research, the science of microbiology can be divided into several branches.

Immunology - the study of the body's natural defence mechanisms against disease- causing microorganisms.

Virusology (virology) - the study of viruses.

Microbial genetics and molecular biology - the study of the genomes and structure of microorganisms. The principles of microbial genetics are used in genetic engineering.

Medical microbiology - studies the interaction between the human body and different types of microorganisms.

Veterinary microbiology - studies the interaction between animals and different types of microorganisms.

Industrial microbiology - studies and develops different applications of microorganisms in different industries. It includes agricultural, pharmaceutical and food biotechnology as well as the production of biological weapons.