BACTERIA Chapter 18 p. 516

Many scientists believe that the first organisms on Earth were microscopic, single-celled organisms called prokaryotes Prokaryotes means: before a nucleus

2 Domains Domain Bacteria – true bacteria Found in all environments except extreme environments Domain Archaea – extremophiles Found in hostile environments Barophiles Deep sea vents Halophiles Salty environments Thermoacidophiles Hot and acidic environments Methanogens Digestive tract of humans

BACTERIA Characteristics Conditions in which bacteria grow Unicellular Prokaryotic Microscopic Conditions in which bacteria grow Heat Moisture Food Cell Phones - Bacteria Growth Bacteria growth - fruit

Bacteria contain the following structures DNA cell wall thin plasma membrane Flagella - movement cilia - movement Pili – helps with reproduction Capsule – prevent drying

3 Shapes bacteria can take Cocci round Bacilli rod Spirilla spiral

Rod-Shaped Bacteria

Spherical Bacteria

Spiral-Shaped Bacteria Borrelia burgdorferi Spirochete:

3 arrangements bacteria can have Staphlo Grape like clusters Strepto chains Diplo pairs

Staining Bacteria Gram negative red double layer more pathogenic Gram positive purple single layer

Bacteria can reproduce 3 ways: Binary fission Bacteria Growth bacteria divides into 2 identical cells

Conjugation Uses protein bridge called a pilus process by which bacteria exchange genetic information Uses protein bridge called a pilus no new offspring are produced

Spore Formation allows bacteria to remain dormant when conditions are unfavorable to reproduce has thick internal wall that protects DNA

How do scientists study bacteria growth? bacteria is grown on an agar rich gel can determine the shapes and arrangement of the bacteria then different types of medicine is used to see what is effective Antibiotics Antibiotic Resistance

Bacterial Metabolism Obligate aerobes – Obligate anaerobes – Heterotrophs – Photoautotrophs - Chemoautotrophs – Extreme Metabolic Ranges

Bacterial diseases: What are they and what do they affect? Gram + infections: Streptococcus Strep throat Staphylococci (staph infection)

Diphtheria membrane becomes inflamed over windpipe Botulism Food poisoning

Tetanus caused by deep puncture wound produces poisons and toxins which over stimulates the nervous system causes muscle spasms commonly known as lock jaw

Gram – infections Acid Fast infections E. Coli found in your intestine improperly processed meat Acid Fast infections TB –(tuberculosis) affects the lungs

Leprosy (Hansen's Bacillus) attacks and destroys nerves causes deformities, even loss of parts

VIRUSES What is a virus made of? non cellular DNA or RNA protein coat

Properties / Characteristics dormant unless in a host cell reproduce only when in a host cell all energy derived from host smaller than a bacteria cell

Cycle of a virus Lytic Cycle attaches to the cell injects its DNA or RNA into cell viral DNA programs cell RNA to produce viruses as a result shuts down cell activity cell bursts and releases viruses Video

Lysogenic Cycle attaches to cell DNA of virus enters cell and is inserted into the DNA of the host cell prophage lies dormant for many years

becomes active because of stress or change in body lytic cycle begins

Viruses can be transmitted in 4 ways: coughing, sneezing

ingesting infected food animal bites

physical contact bodily fluids

Viral Infections glands in your neck tired, headaches Mononucleosis or Herpes 2 glands in your neck tired, headaches Corona virus causes bronchitis

Mumps causes the swelling of the salivary glands, can affect other organs as well Measles usually affects the skin can affect the respiratory system, brain

attacks the spinal cord Chicken pox Poliomyelitis (polio) attacks the spinal cord

Herpes 1 common cold sore Conjunctivitis pink eye

How are viral infections cured? no known antibiotic or treatment body’s is its own natural defense mechanism must run its course can only treat the symptoms when body detects virus (antigen), body produces antibodies called plasmacytes fight off viruses remains in blood a single attack of a virus usually results in lifelong immunity Can viral infections repeat themselves?

What is an immunization? weakened or killed virus strain cannot cause disease helps to produce the stimulation of antibody production immunizations are used against Polio Measles Chicken pox Mumps Influenza (flu)

What is a retrovirus? contains RNA instead of DNA works backwards example HIV -- Aids

ANTIBIOTICS Antibiotics powerful medicines that fight bacterial infections when your own immune system cannot effective because they either kill bacteria or keep them from reproducing. Why effective? because bacteria reproduce by binary fission, all of the bacteria are the same