Author: Nathan Lampson
This lesson will provide the characteristics of the domain Bacteria.
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Introduction to Psychology

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When a person becomes sick due to Strep Throat, it is a result of a bacterial organism called Streptococcus.  Bacteria that cause illness or disease are known as pathogens.


Bacteria aren't always harmful, the bacteria found in the human digestive tract help to digest food and keep us healthy. In return, the digestive bacteria get energy from the food we eat.  This relationship between humans and bacteria where both organisms benefit is known as a mutualistic relationship. 


Bacteria must possess certain characteristics in order to be considered bacteria.



The cell walls surrounding bacteria is made of a substance called peptidoglycan.  Peptidoglycan is a material containing sugar and amino acids.



Bacterial organisms are unicellular and are made of just a single cell.



Bacterial cells do not contain organelles or membrane bound nuclei.  


Autotroph or Heterotroph

Organisms that are classified as bacteria can either produce their own nutrients or get nutrients by consuming other organisms.