KINGDOMS OF ORGANISMS

Kingdoms Archaebacteria and Eubacteria (a.k.a. Monerans)

Characteristics of the Kingdoms Archaebacteria and Eubacteria No membrane-bound nucleus No membrane-bound organelles Cell membrane Unicellular Smaller than almost all organisms Prokaryotic

Structures in a Typical Bacteria Flagella—long hairlike structures growing from a

cell that aid in movement Chromosome—usually a single, circular piece

of DNA Ribosome—used for making proteins Plasmid—small circular piece of DNA Cell membrane (a.k.a. plasma membrane)—

separates the cell from its external environment Pili—short, hairlike structures involved in

reproduction and cell-to-cell contact Cell wall—protects and support the cell Capsule—located around the cell wall; bacteria

with capsules are more likely to cause diseases

Endospores

Thick walled structures that can resist heat, drought, and radiation

Bacterial cells can form endospores when living conditions become unfavorable

Reproduction

Binary Fission:Cell division in which the cell forms

2 identical cells It is a form of asexual reproduction

Reproduction (cont.)

Conjugation:Process of exchanging genetic material

though cell-to-cell contactDNA and plasmids move through the pili from

one bacterial cell to another

Transformation

Picking up and incorporating DNA from dead bacterial cells

Classification of Bacteria

Cell Shape:Spheres—cocciRods—bacilliSpirals--spirilla

Respiration:Aerobes—use oxygenAnaerobes—do not use oxygen

Classification of Bacteria (cont.)

Cell Wall Composition:Gram positiveGram negative

Nutrition:AutotrophsHeterotrophs—most bacteria are

heterotrophic

Roles of Bacteria in the Biosphere

Decomposers: break down organic materials

Bioremediation: bacteria are used to rid the environment of harmful substances (i.e. oil spills)

Manufacturing: bacteria are used to ferment sugar to make cheese, yogurt and some beverages

Roles of Bacteria in the Biosphere (cont.) Medicine: bacteria are used to make human

proteins such as insulin Nitrogen fixation: provides usable nitrogen for

plants; ex: bacteria that live on roots of legumes Symbiosis: relationship between 2 organisms in

which at least one of the partners benefits; ex: bacteria found in the intestines of mammals help with digestion and provide vitamins

Pathogens

Bacteria that cause diseases are called pathogens

Some pathogens use the body’s cells as food; ex: mycobacterium tuberculosis

Other pathogens release toxins that can travel throughout the body; ex: streptococcus

Vaccines

An injection of dead bacteria or virus will stimulate the immune system to make antibodies

The antibodies will provide immunity against the disease

Antibiotics

Antibiotics can work to block bacterial cell growth and reproduction

Some antibiotics, like penicillin, attack the cell wall of the bacterial cells

Penicillin makes holes in the wall causing water to rush into the cell and rupturing it

Bacteria Wanted Poster Research Project

http://www.accessexcellence.org/AE/ATG/data/released/0210-JoyceCalo/

W A N T E D

Helicobacter pyloriDescription: spiral-shaped, Gram-negative bacteriaM.O.: attacks the mucus layer of the stomach and duodenumVictims: attacks humans and destroys the mucus layer causing ulcers and can lead to cancer; can infect individuals who remain symptom free so number of victims is unknownHideout: found in epithelium below the mucus layer of the stomach and duodenumWeapons: combination therapy—antibiotics and acid reducers