Bacteria: Classification and Structure

What are the 6 Kingdoms? Archaebacteria Eubacteria Protists Fungi Plants Animals

We are looking at the first two Archaebacteria Eubacteria

Classification of Bacteria Archaebacteria: extremists Eubacteria: –Heterotrophs –Photosynthetic autotrophs –Chemosynthetic autotrophs

Archaebacteria Live in extreme locations: –Oxygen-free environments –Concentrated salt-water –Hot, acidic water

Eubacteria - Heterotrophs Found everywhere Parasites: live off of other organisms Saprobes: live off of dead organisms or waste (recyclers)

Eubacteria: Photosynthetic Autotrophs Photosynthetic: make their own food from light Cyanobacteria: blue-green, yellow, or red ponds, streams, moist areas

Eubacteria: Chemosynthetic Autotrophs Get energy by breaking down inorganic substances like sulfur and nitrogen Make nitrogen in the air usable for plantsMake nitrogen in the air usable for plants {Very Important}

Structure of Bacteria Two parts to Bacteria Structure: –Arrangement –Shape

Arrangement Paired: diplo Grape-like clusters: staphylo Chains: strepto

Shape Rod: bacillus Spheres: coccus Spirals: spirillum

Examples Streptococcus: chains of spheres Staphylospirillum: Grapelike clusters of spirals Streptobacillus: Chains of rods

Typical Bacterial Cell

Reproduction Two types of reproduction –asexual –sexual Asexual: Binary Fission: –genetically identical –rapid reproduction; can be as little as 20 minutes in some bacteria this rate they could cover the surface of the earth in a few weeks) WOW!!! Note: Bacteria don’t always have the ideal growing conditions and they often run out of nutrients and water, poison themselves with their waste, and predators eat them.

Reproduction Sexual : Conjugation –During conjugation, one bacterium transfers all or part of its chromosome to another cell through the pilus (plural: pili) that connects the two cells. –These bacterial cells can now go through binary fission and produce cells with the new recombinated DNA. Click video below!!!

Bacterial Respiration & Metabolism Obligate aerobes: –Bacteria that require oxygen Obligate anaerobes: –Bacteria that are killed in the presence of oxygen There are some bacteria that can survive in either condition: –Oxygen present: cellular respiration –Oxygen absent: fermentation

Survival Tactic When bacteria are faced with adverse (unfavorable) conditions they can produce an endospore. –Endospore: a tiny structure that contains a bacterium’s DNA and a small amount of its cytoplasm, encased by a tough outer covering that resist drying out, temperature extremes, and harsh chemicals. Click video below!!!

Importance & Benefits of Bacteria Nitrogen fixation: –Nitrogen is essential (necessary) for all organisms Found in DNA, RNA, proteins, and ATP –Only bacteria can convert the nitrogen gas in the atmosphere to nitrogen that other organisms can use Example: legume plants roots and nitrogen fixation bacteria (p. 493)

Importance & Benefits of Bacteria Recycling of nutrients –Decomposing bacteria break down organic (containing carbon) matter in dead organisms and wastes, returning organic and inorganic materials back to the environment.

Importance & Benefits of Bacteria Food and Medicine: –Food: Swiss cheese, blue cheese, vinegar, sauerkraut, etc. Live in the intestines of animals, and produce vitamins and enzymes that help digest food. –Medicine: Can be used to make antibiotics to kill other types of bacteria –streptomycin, erythromycin, bacitracin, and neomcin

Harmful Effects Bacteria can cause disease –Antibiotics, such as penicillin can help combat bacteria by inhibiting bacteria cells from properly forming a cell wall. Water enters the cell and they rupture and die