Bacteria can be good and bad. Some help in your digestive
tract. Others can make a person sick. Bacteria can live on and inside every
living thing. It is on animal fur and plant leaves. Bacteria is in soil.
Bacteria is also in lockers at school. Bacteria is an important part of life
science. Bacteria’s structure, reproduction, and various types are helpful to
understanding living organisms.
Anton van Leeuwenhoek was the person who discovered
bacteria. He was a Dutch amateur scientist. He studied them under a microscope
because they are microscopic and only measure 0.3 to 2.0 microns in diameter. Bacteria,
plural for bacterium, and viruses are the smallest living things on Earth.
Bacteria’s DNA is carried in genes inside the nucleoid. (“Bacteria” and
Vidasager) Bacterial cells also hold circular pieces of DNA called plasmids.
(Vidasager) Bacteria are about 80% to 90% water. This means that they do not
have a complex build and are simple. Other ways bacteria are simple is that
they are prokaryotes and are made of one cell. Prokaryotes do not have a
nucleus. Bacteria usually have no organelles because they do not have a
nucleus. Flagella help bacteria move. Pili help bacteria connect to host
organisms and other bacteria. (Vidasager)
Bacteria reproduce by binary fission. Binary fission can
take between 15 minutes and 16
hours. The type of
bacteria determines the amount of time it takes to reproduce. (“Bacteria”) When
the bacteria reproduce by binary fission, two cells are made from one. There
are about 50 million bacterial organisms in a gram of common soil. This shows
that they reproduce very quickly and are capable of this fast division. The
domain bacteria can be separated into two groups. These groups are Eubacteria
There are three main types of bacteria. They are cocci,
bacilli, and spirilla. Cocci are round, while bacilli are cylinder-like and
spirilla are spiral. Spirilla can differ from comma-like shapes to loose spiral
coils. Spirochetes, similar to spirilla, are corkscrew-shaped. Cocci can occur
in four ways. They can occur singly, in couples, chains, and clusters. Singly
is called coccus, couples is diplococci, chains is streptococci, and clusters
are staphylococci. Bacilli usually form alone, but some form in chains. When
bacilli form in chains, they are called streptobacilli. (Urry) Bacteria can
occur in almost any place.
There are some bacterial extremophiles that live in hot
places, like hot springs, and some that live in cold places, like artic
environments. Bacterial extremophiles can also live in radioactive waste, deep
sea oil seeps, deep Earth crustal environments, hypersaline ponds, and within
other living organisms. Bacterial extremophiles can live in many different
environments. (Patterson) Other bacteria live in many different places, too.
In life science, bacteria is useful to study. They have
an effect on almost every living thing. Bacteria share many characteristics.
All bacteria have a simple structure. They all also reproduce by binary
fission. There are several types of bacteria and forms they occur in. Bacterial
extremophiles live in many places regular bacteria would not live in.
Understanding bacteria better helps doctors and scientists treat diseases and
solve other problems.