Bacteria are small living things that can be found almost everywhere. They live on the ground, in oceans, in the food that we eat and even in our bodies. They have been on earth long before there were any other organisms .Bacteria are so small you can only see them with the help of a microscope. They have only one cell and very simple structures.

Bacteria have outer cell walls that protect the inside. A cell membrane is inside the cell wall. It prevents harmful substances from getting in and out. Inside the membrane is a soft, jelly-like substance called the cytoplasm. It has chemicals that help build the parts of a cell and break down food. Within it is the nucleoid, which contains the DNA. It controls a cell’s growth and other activities

Bacteria appear in different shapes. Spherical bacteria are round or ball-like. Rod-shaped bacteria live in your intestine and form chains. Spiral-shaped bacteria have a twisted form.

Bacteria absorb nutrients and remove waste through their cell walls. They reproduce by splitting themselves in the middle. The two new cells can then split into four cells and so on. In a short time a single bacteria can reproduce billions of times.


Structure of bacteria

Structure of Bacteria

Some bacteria can get inside the human body, reproduce and cause an infection. These harmful bacteria are called pathogens.  Our immune system is in charge of fighting off these bacteria.  However, sometimes we need a vaccine to help fight off these intruders. Vaccines are weak or dead forms of the bacteria itself. Such a substance helps our body fight off bacteria in the future.  Some examples of illnesses caused by bacterial infections are tuberculosis or pneumonia.

The best way to protect yourself form bacteria is to keep yourself clean and wash your hands. Because bacteria may be transported by air, we should cover our nose and mouth when we sneeze. Vitamins also help strengthen our immune system and fight off bacteria.

Bacteria can be helpful to the human body as well. They live in our stomach and help us digest food. Other bacteria create cheese and yoghurt.  Bacteria are at work in the soil and decompose dead plants and animals.


Related Topics



  • absorb = take in
  • appear =show
  • break down = break into very small pieces
  • cause = lead to
  • chain = rings that are joined together
  • decompose = to break down into very small parts
  • digest = to change food that you have eaten into substances that your body can use
  • DNA = substance that has the genetic information in the cells of a body
  • growth = how something grows
  • harmful = dangerous
  • however = but
  • illness = disease
  • immune system = system in your body that protects it from diseases
  • intestine = long tube in your body through which food passes after it leaves your stomach
  • intruder = here: something harmful that gets into your body
  • jelly = something soft and sticky; it can easily move when you touch it
  • membrane = very thin layer that covers an object and protects it
  • nucleoid = region in a cell
  • nutrient = chemical or food that gives plants and animals what they need to grow
  • organism = anything that lives
  • pneumonia = illness that affects your lungs and makes it difficult for you to breathe
  • prevent = stop, keep away
  • protect = guard, care for, defend
  • remove = bring away
  • reproduce = here: create new bacteria
  • rod = long and thin
  • shape = form
  • single = only one
  • sneeze = air comes suddenly through your nose with a loud noise
  • soil = the top layer of the earth, where plants and trees can grow
  • spherical = round like a ball
  • strengthen = make stronger
  • structure = the way something is built
  • substance = material
  • transport = travel
  • tuberculosis = disease that affects your lungs and other parts of your body
  • twisted = turned, bent
  • waste = material that we do not need