Basic Facts
- Can live in any sort of habitat
- Can be harmful (pathogen) or helpful
- Can proliferate quickly
- Two kingdoms, eubacteria and archaea
Characteristics
- Single cellular
- Prokaryotic (no membrane bound organelles)
- DNA forms one single chromosome
- Reproduce by binary fission (asexual)
- Contain a plasmid, which is a small loop of DNA containing genes
Structure of Bacteria
Classification of Bacteria
Bacteria is classified using three characteristics:
Bacteria can be three different shapes; Coccus (spherical shaped), Bacillus (rod shaped) and Spirillum (spiral shaped).
- Respiration (metabolism)
- How they acquire nutrients
- Their shape
Bacteria can be three different shapes; Coccus (spherical shaped), Bacillus (rod shaped) and Spirillum (spiral shaped).
Bacteria are also classified by numbers.
Cocci that live individually are called monococci.
Cocci that live in pairs are called diplococci.
Cocci that live in chains are called streptococci.
Cocci that live in clusters are called Staphylococcus.
Cocci that live individually are called monococci.
Cocci that live in pairs are called diplococci.
Cocci that live in chains are called streptococci.
Cocci that live in clusters are called Staphylococcus.
Bacili that live individually are called monobacili.
Bacili that live in pairs are called diplobacili.
Bacilli that live in chaines are called streptobacili.
Bacili that live in pairs are called diplobacili.
Bacilli that live in chaines are called streptobacili.
Bacteria Respiration
Bacteria lack some organelles such as mitochondria and chloroplasts, but can still carry out the same functions.
For all respiration, some bacteria need oxygen and some don't.
Aerobe- need oxygen to produce energy.
Anaerobe- do not require oxygen to produce energy.
There are two types of Anaerobe bacteria:
Aerobic cell respiration and oxygen produces energy.
Anaerobic cell respiration and hydrogen, sulphur or iron produces energy.
For all respiration, some bacteria need oxygen and some don't.
Aerobe- need oxygen to produce energy.
Anaerobe- do not require oxygen to produce energy.
There are two types of Anaerobe bacteria:
- Facultative Anaerobe- can live in environments with or without oxygen.
- Obligate Anaerobe- can only live in environments without oxygen.
Aerobic cell respiration and oxygen produces energy.
Anaerobic cell respiration and hydrogen, sulphur or iron produces energy.
Bacteria Gram Stains
Bacteria gram stain are based on physical and chemical properties of the cell wall.
The cell wall is composed of Peptidoglycan, which is a layer of the cell wall made of sugar and amino acids. If bacteria absorbs the stain and turns purple it is gram-positive bacteria. If bacteria does not absorb the stain and turns pink is gram-negative bacteria. |
Bacterial Reproduction
Bacteria reproduce by binary fission.
Two other ways bacteria reproduce are:
Conjugation- genetic information is transferred through the pili, therefore two cells share DNA, therefore sexual reproduction.
Transformation- bacteria picks up loose fragments of DNA from old, dead cells.
Conjugation- genetic information is transferred through the pili, therefore two cells share DNA, therefore sexual reproduction.
Transformation- bacteria picks up loose fragments of DNA from old, dead cells.