Facts At Your Fingertips: The living world – Microlife
Bacteria and protists are single-celled organisms that can only be seen using a microscope. Bacteria are so small that 10,000 could fit on the head of a pin.
Microlife is found all around us, and even inside us—there are 10 times as many bacteria in our bodies as there are cells!
Protists
These single-celled organisms are found anywhere there is water. Some, such as protozoa, move around and feed on other protists or on bacteria.
Others, such as algae, make their own food using the energy of the Sun, like plants. Sometimes protists come together in huge colonies of billions of individual cells.
Good bacteria
Special bacteria in our stomachs help us to digest food. We can also use bacteria to make our food. The varied flavors of different kinds of cheese are produced with the help of bacteria.
Bad bacteria
Diseases such as cholera and tetanus are caused by harmful bacteria. We protect ourselves from these bacteria with vaccines.
A vaccine is a safe dose of a less harmful form of the bacteria that make us sick.
This makes our bodies produce antibodies, special proteins that will fight off the harmful forms if they ever appear in the future.