Download Bacteria Notes

Bacteria Notes
Much of what we know about bacteria was learned by scientists fighting bacterial diseases. But of the
thousands of types of bacteria, only a few hundred cause disease.
Essential Vocabulary:
1. Prokaryote - an organism that consists of a single cell that does not have a nucleus
2. Binary fission - a form of asexual reproduction in single -celled organisms by which
one cell divides into two cells of the same size
3. Endospore - a thick-walled spore that forms inside a bacterial cell and resists harsh
conditions
4. Bioremediation - a biological treatment of hazardous waste by living organisms
5. Antibiotic - medicine used to kill bacterial and other harmful microorganisms
6. Pathogenic bacteria - bacteria that causes disease
7. Virus - a microscopic particle that get s inside a cell and often destroys the cell
8. Host - an organism from which a parasite takes food or shelter
Characteristics of Bacteria

Most bacteria have a rigid cell wall that gives them their shape

Bacteria are single-celled organisms that are usually one of three main shapes… rod, sphere, or
spiral

All bacteria are prokaryotes, single-celled organisms that do not have a nucleus

Bacteria reproduce by the process of binary fission. The stages of binary fission include
i.
The cell grows
ii.
A ring of DNA is copied and attached to the cell membrane
iii.
The DNA and its copy separate as the cell grows larger
iv.
The cell splits in two (each new cell has a copy of the DNA

Some bacteria have hair like parts called flagella that help them move around

Bacteria make up the kingdoms Eubacteria and Archaebacteria. These two kingdoms contain the
oldest forms of life on Earth
Eubacteria (true bacteria) – this kingdom has more individuals than all the other five kingdoms
combined. Scientists think that eubacteria have lived on Earth for more than 3.5 billion year. Eubacteria
are classified by the way they get food. Most are consumers.

Consumers – bacteria that get food from other organisms
Decomposers - consumers that feed on dead organisms, bacteria are the major decomposers on Earth

Producers – bacteria that make their own food
Cyanobacteria – cells contain the green pigment chlorophyll (usually live in the water
Archaebacteria (ancient bacteria) – three main types that often live in harsh environments
Heat lovers – live in hot water such as hot springs and thermal vents
Salt lovers – live in high levels of salt such as the Dead Sea, and the Great Salt Lake
Methane makers – live in swamps and animal intestines… give off methane gas
Good for the Environment:
Nitrogen Fixation –The process by which nitrogen-fixing bacteria take nitrogen from the air and change
it to a form that plants can use.
Recycling nutrients – decomposing bacteria break down dead plant and animal matter making the
nutrients available for other living things.

Bioremediation – bacteria (and other microorganisms) are used to change harmful chemicals into
harmless ones. The process cleans-up hazardous waste from industries, farms, cities, and oil spills.
Good for People:

Food – people raise bacteria for food… examples include cheese, yogurt, buttermilk, and sour cream

Medicine – insulin for diabetics and many antibiotics are made by genetically engineered bacteria

Genetic engineering – scientist change the genes in bacteria to make many products including
insecticides, cleansers, and adhesives
Harmful Bacteria:

Pathogenic bacteria – get inside a host organism and take nutrients from the host’s cells