Bacteria 2 Kingdoms : Eubacteria (in domain Bacteria) 2 Kingdoms : Eubacteria (in domain Bacteria) & Archaebacteria (in domain Archae) & Archaebacteria (in domain Archae) - eubacteria larger of 2 kingdoms, cell walls contain peptidoglycan (a carbohydrate) walls contain peptidoglycan (a carbohydrate) - archaebacteria lack peptido. Thought to be ancestors of eukaryotes. ancestors of eukaryotes. Identification is mostly by shape: Identification is mostly by shape: Bacilli – are rod shaped Bacilli – are rod shaped Cocci are spherical Cocci are spherical Spirilla are spiral or corkscrew Spirilla are spiral or corkscrew

Cell walls: one identification technique is done by Gram Staining. (some retain dye where others do not) Has to do with lipid and peptidoglycan content in cell wall Cell walls: one identification technique is done by Gram Staining. (some retain dye where others do not) Has to do with lipid and peptidoglycan content in cell wall Movement – can be by flagella. Others may glide or twist (spirilla). Others don’t move at all. Movement – can be by flagella. Others may glide or twist (spirilla). Others don’t move at all. Gets energy – some are autotrophic, some are heterotrophic Gets energy – some are autotrophic, some are heterotrophic

Growth & reproduction – bacteria produce 2 daughter cells in a process called binary fission. Some produce spores (endospore) where they remain dormant until favorable conditions arise. Growth & reproduction – bacteria produce 2 daughter cells in a process called binary fission. Some produce spores (endospore) where they remain dormant until favorable conditions arise. Many bacteria are decomposers. Many bacteria are decomposers. Others “fix” nitrogen. These bacteria attach to certain plant roots and convert atmospheric nitrogen to a useable form that the plant can use (process is called nitrogen fixation) Others “fix” nitrogen. These bacteria attach to certain plant roots and convert atmospheric nitrogen to a useable form that the plant can use (process is called nitrogen fixation)

Disease: some bacteria are pathogenic (disease causing). Done either by Disease: some bacteria are pathogenic (disease causing). Done either by Damaging tissues Damaging tissues Releasing toxins Releasing toxins Antibiotics – used to control bacterial growth. (increased life expectancy) Antibiotics – used to control bacterial growth. (increased life expectancy)

Bacteria can be useful to humans: Bacteria can be useful to humans: Used in food industry (pickles, sauerkraut, vinegar, cheese, yogurt, buttermilk, sour crm) Used in food industry (pickles, sauerkraut, vinegar, cheese, yogurt, buttermilk, sour crm) Controlling growth: Controlling growth: Sterilization – by subjecting to high heat or chemical treatment Sterilization – by subjecting to high heat or chemical treatment Refrigeration – reduces growth for awhile Refrigeration – reduces growth for awhile

Viruses Definition: particles of nucleic acid and protein that reproduce only by infecting living cells Definition: particles of nucleic acid and protein that reproduce only by infecting living cells Viruses are coated by protein (called a capsid) Viruses are coated by protein (called a capsid)

Viral Infections Lytic – virus enters host cell, and makes copies. Cell enlarges, then is destroyed (bursts) Lytic – virus enters host cell, and makes copies. Cell enlarges, then is destroyed (bursts) Lysogenic – viral particle moves into cell & replicates. Does not destroy host but is then replicated along with host cell. Lysogenic – viral particle moves into cell & replicates. Does not destroy host but is then replicated along with host cell.

Retroviruses Contain RNA. They turn RNA into DNA using cell materials. (Retro) Contain RNA. They turn RNA into DNA using cell materials. (Retro) These viruses are responsible for some cancers in animals. Also HIV (the virus causing AIDS) These viruses are responsible for some cancers in animals. Also HIV (the virus causing AIDS)

Prions No genetic material – just protein. (Mad Cow Disease). Particles show up in nerve tissue (brain) No genetic material – just protein. (Mad Cow Disease). Particles show up in nerve tissue (brain) Viroids A single strand of RNA that has no capsid. These affect mostly plants A single strand of RNA that has no capsid. These affect mostly plants

Host Cell Specificity Viruses are restricted to certain kinds of cells. Example: viruses that affect plants do not affect animals Viruses are restricted to certain kinds of cells. Example: viruses that affect plants do not affect animals

No genetic material – just protein. (Mad Cow Disease). Particles show up in nerve tissue (brain) No genetic material – just protein. (Mad Cow Disease). Particles show up in nerve tissue (brain)

Important viral diseases in Humans AIDS – transmitted by sexual contact, contaminated blood AIDS – transmitted by sexual contact, contaminated blood Hepatitis A & B – same Hepatitis A & B – same Influenza (flu) – acquired by inhalation Influenza (flu) – acquired by inhalation Mumps – same Mumps – same Rabies – Transmitted by animal bite Rabies – Transmitted by animal bite SARS - inhalation SARS - inhalation

Important bacterial diseases in humans Bubonic Plague – transmitted by flea bite Bubonic Plague – transmitted by flea bite Cavities – Dense collections of oral bacteria Cavities – Dense collections of oral bacteria Tuberculosis – inhalation Tuberculosis – inhalation Lyme disease – bite from infected tick Lyme disease – bite from infected tick Cholera – aquired from drinking contaminated water Cholera – aquired from drinking contaminated water