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How Do Bacteria
Reproduce
By Patrick O'Hare
Earth.com staff writer
Many of us interact with bacteria on a daily
basis. If you eat yogurt or cheese you can thank bacteria!
They are so common that there are about as
many bacterial cells as human cells in your body.
Their diversity is also stunning. Recent
estimates found that there are over one billion different types of bacterial
species.
Even though bacteria may seem wildly
different than humans, we all do have at least one thing in common: we all
undergo reproduction.
Bacteria definitely don’t reproduce like
humans or other animals, so exactly how do bacteria reproduce?
Domains of Life
Before we talk about how bacteria reproduce,
we need to understand their place in biology.
Scientists think we all came from one common
ancestor. Since then, living organisms have changed greatly.
The first way to distinguish one organism
from another is by classifying what domain it falls into.
Current classification uses three domains:
eukarya, archaea, and bacteria.
Bacteria are then grouped into five major
categories: proteobacteria, cyanobacteria, chlamydiae, spirochetes, and
firmicutes.
Bacterial Uses
Bacteria are all around us. From our bodies
to our food. From the hottest deserts to the coldest tundras.
Between the highest mountains to the deepest
oceans, bacteria live everywhere.
Over the last several thousand years, we
humans have learned to use bacteria to our benefit.
Let’s take a look at some of the unique ways
we use bacteria.
Cheese
Cheesemaking brings together everybody’s
favorite ingredients: milk, salt, and bacteria.
A necessary step in almost all cheese
production is the separation of the two products of curdling: curds and whey.
This process is accomplished by acidifying the
pre-cheese mixture. While this can be accomplished by adding acid directly,
more often, various types of starter cultures are used.
The starter bacteria accomplish two things.
First, they digest the milk sugars and turn them into lactic acid.
Second, they help to develop the flavor
protein of the cheese. Different bacteria are used for different cheeses.
Interestingly, certain strains of bacteria
even help to give some cheese their awful smell.
Composting
Composting is a method of using bacteria and
air to break down organic solids. In other words, it can be an easy, at-home
way to sustainably get rid of your food waste.
Typically, it will involve a large, covered
container that stores the waste.
First, it needs to be placed in the sun and
given the room to ventilate. After that, the composter becomes the perfect home
for billions of bacteria.
The bacteria come from many places. Whereas
some come from the surfaces of the waste or our hands, others exist in the
ambient environment.
They slowly break down the scraps and waste
into organic fertilizer. Alternatively, it can now be safely disposed of in a
much more environmentally friendly manner.
Bioremediation
Bioremediation is the process of using living
organisms to clean up a polluted area.
Bacteria are capable of utilizing dangerous
heavy metals, like lead, and transforming them into other compounds that are no
longer dangerous.
What’s more, recent studies have made
significant headway into showing the possible uses of bioremediation
technology.
Scientists are hopeful that these processes
can help with mining accidents and even oil spills.
Reproduction
Now that we understand where bacteria fit and
what they’re used for, let’s take a look at how they reproduce.
Binary Fission
The most common way for bacteria to reproduce
is through binary fission. The basics of the process are simple.
First, the cell grows to approximately double
its normal size.
Next, it makes a copy of all of its genetic
material. This is through a process called DNA replication.
Last, the cell actually splits down the
middle into two identical ‘daughter’ cells. This process is roughly the same as
how our body cells reproduce.
Specifically, binary fission is a type of
asexual reproduction because there is no exchange of genetic material at the
time of the split.
Baeocyte Production
Baeocyte production is very different from
binary fission.
Contrary to binary fission which copies
genetic information once, some types of bacteria will copy their DNA dozens and
dozens of times.
After the copying is complete, the ‘parent’
cell will rapidly divide dozens or hundreds of times.
As a result, dozens or even hundreds of new
baeocytes form. This is a common process found in cyanobacteria.
Budding
Budding is a reproductive strategy that is
more commonly seen in eukaryotic single-celled organisms, like yeast.
Essentially, the bacteria stretch out into
large, thin cells with a set of ‘arms’ around the center. Each of these arms is
the site of a ‘budding’ event, whereby new buds can break off.
Each of these buds can go on to be a fully
functioning adult bacteria. These bacteria, themselves, will undergo budding.
While less common, this process takes place
for many different bacteria across the whole domain of bacteria. Indeed, you
can find the process of budding in almost all major types of bacteria.
Wide World of Bacteria
We’ve now seen that bacteria can live almost
anywhere, and their diversity of uses is paralleled by their unique strategies
of reproduction.
Next time you’re eating a cultured food think
about the fact that bacteria helped create it!
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