Life comes in many shapes, forms and sizes and a huge amount of the life on Earth is so small that humans can only see them with the use of a microscope. A number disciplines in of biology, such as microbiology, biochemistry and genetics, are focused entirely on studying the microscopic forms of life and the molecules that allow life to exist.

The study of the microscopic world falls into two main categories. Firstly there the study of microscopic organisms or microorganisms. These organisms exist in huge masses and make up as much as 90% of the world’s living activity. Microscopic organisms include all Bacteria and Archaea, a huge number of fungi, all protists and a number of plants and animals.

The second branch of microscopic biology is the study of the structures and compounds that make an organism. All organisms have at least one cell and many have trillions of cells. The cells of the various life forms on Earth are incredibly diverse and have evolved a huge range of different structures for different purposes.

The field of biochemistry looks at the structure and behavior of molecules such as proteins and carbohydrates. These molecules drive important processes such as photosynthesis and respiration. Cell biology studies the different types of cells and the structures found within cells such as organelles. Genetics is a field of biology that studies DNA and genes and how cellular information is passed from one a parent to its offspring.


Cells are the basic unit of life. They are the most reduced structures capable of sustaining life. Some living things such as bacteria only have a single cell while other organisms can have many cells. Some of the most advanced organisms contain more than one trillion cells.


Genetics is a discipline of biology that studies genes and the passing of characteristics from one generation to the next which is known as heredity. Genetics and heredity are core topics of biology and includes topics such as DNA, chromosomes and transcription.


Biochemistry is a field of biology that studies the chemical reactions within living organisms. Life is simply a series of hundreds of thousands of chemical reactions and biochemistry studies the molecules and chemical pathways found in living things.


The vast majority of the world’s organisms are invisible to the naked eye. Microscopic organisms, known as microorganisms or microbes, are found in almost every environment on Earth – from the deepest oceans to thermal hot springs and the insides of animals and plants.