Bacteria Chapter 23

Bacterial Classification Section 23.1

REVIEW: All Bacteria are Prokaryotes “Before nucleus” No nucleus No membrane bound organelles Eukaryotes: “True nucleus” Have nucleus Have membrane bound organelles

Two Domains of Bacteria DIFFERENCES BASED UPON RNA MAKEUP Domain Bacteria Kingdom Eubacteria Domain Archaea Kingdom Archaebacteria More related to eukaryotes based upon rRNA & gene comparison

1. Domain Archaea Lack peptidoglycan (protein-carbohydrate compound) in cell wall Usually located in extreme conditions like: swamps, salt lakes, and hot springs Three main types: A. Methanogens B. Extreme halophlies C. Thermoacidophiles Pyrodictium occultum is a  marine organism commonly found in deep-sea hydrothermal vents.

A. Methanogens Energy source: from converting H2 and CO2 into methane gas. Live in areas absent of oxygen like swamps, sewage, and intestinal tract

B. Extreme Halophiles Salt loving bacteria Location: anywhere there is a high salt concentrations like the Great Salt Lake and the Dead Sea. Energy source: salt need for them to make ATP

C. Thermoacidophiles hot and acidic enviornments They are found in such places as acidic sulfur springs, undersea vents (smokers) and volcanoes

2. Domain Bacteria Most abundant domain! Examples: Cyanobacteria, chlamydia, Lyme Disease, botulism, TB, E. coli, anthrax, nitrogen-fixing bacteria Classified based on: Gram stain Shape Biochemical properties

Gram Stain Gram Positive Bacteria Simple cell wall with lots of peptidoglycan Stains purple Gram Negative Bacteria Complex cell wall with little peptidoglycan Stains pink

Bacterial Shapes Spirilla (spiral-shaped) Bacilli (rod-shaped) Cocci (sphere-shaped) Streptococci – long chains Staphylococci - clusters

Bacterial Groups Proteobacteria Gram-Positive Bacteria Cyanobacteria Spriochetes Chlamydia

Video 1. Proteobacteria Largest and most diverse group Many live symbiotically with other organisms Nitrogen-fixing bacteria Some cause diseases Rocky Mountain spotted fever Stomach ulcers Foodborne illnesses Video

2. Gram-Positive Bacteria Some cause diseases Strep throat Botulism (Botox) Anthrax TB Leprosy A few make antibiotics that kill other bacteria

3. Cyanobacteria Undergo photosynthesis for energy Simplest life requirements First oxygen-producing organisms on Earth!

4. Spirochetes Gram-negative Spiral-shaped bacteria Examples: syphilis & Lyme disease

5. Chlamydia Gram-negative Coccoid shaped, no peptidoglycan Causes a STD that lives inside animals

Biology of Prokaryotes Section 23.2

Bacterial Structures Most bacteria are composed of the following parts: Outer cell wall Cell membrane Internal foldings = thylakoids (photosynthesis) Cytoplasm Ribosomes DNA Small molecules and ions

Endospores Can form in gram + bacteria Thick-coated, resistant structures Form when environmental conditions are poor Resistant to high temp, strong chemicals, radiation, drying, etc.

Video Prokaryotic Movement Taxis: movement toward or away from stimuli Chemotaxis: chemical stimuli Physical movement aided by flagella or slime Patterns of movement: wave-like contractions or corkscrew rotation Video

How do bacteria reproduce? Asexually via…. Binary fission Budding permits the development of more complex colonial structures Binary fission Budding

Genetic Recombination Three ways that bacteria can exchange and acquire new combinations of DNA 1. Transformation 2. Conjugation 3. Transduction

1. Transformation When a bacteria takes on DNA from its external environment. Then this new DNA is substituted into the bacterial DNA

2. Conjugation When two bacterium bind together and one bacterium transfers genetic information to the other. DNA channeled through the sex pilus Video

3. Transduction Steps: 1. Virus obtains a fragment of bacteria DNA from its host 2. Virus multiplies inside host (replicating the bacterial DNA as well) 3. Virus breaks out of host cell and invades new bacteria 4. New bacterial host will get old host’s DNA via the virus

Know these parts of the bacteria! Cell Wall Outer Membrane Cell Membrane Cytoplasm Chromosome Plasmid Capsule & Slime Layer Endospore Pilus Flagellum p. 468 Click above for more info!

Bacteria and Humans Section 23.3 Video

Bacterial Diseases Pathology – The study of diseases Pathogens – anything that causes disease Bacteria Viruses Fungi Protists

Cholera attacking a cell

Bacterial Poisons Toxins – bacterial poisons that cause disease Exotoxins – made up of proteins Secreted by the gram + bacteria to surroundings Example: tetanus Endotoxins – made up of lipids and carbs. Released by dead gram – bacteria Cause fever, body ache, weakness, and damage

Caused by not taking full dose of antibiotics How to treat diseases… Antibiotics – fungi or bacteria that combat infection by interfering with various cellular functions May lead to Antibiotic Resistance Caused by not taking full dose of antibiotics

Emerging Infection Diseases Zoonosis: a disease that passes from wild animals to humans Increase due to global travel of humans & destruction of natural habitat Example: Lyme disease Other examples Video

Useful Bacteria to Humans Probiotics- useful bacteria in your gut Recycle compounds from dead organisms Create organic compounds Food production (buttermilk, sour cream, yogurt, cottage cheese, sauerkraut, pickles) Produce fuels Insecticides Bioremdiation: break down pollutants Video