Microbiology. Unit 1

What is a microbe/microorganism?

Organisms too small to see with the naked eye

What is meant by the term pathogenic? Are most microorganisms pathogenic?

Disease causing, NO!

What are the beneficial role of microbes?

-     organic decomposition- They decompose organic matter (dead plants/ animals, bacteria)

-       sewage treatment- They filter gross water that large filtration systems cannot

-       food and beverage production- They are used in fermentation

-       antibiotic production – Can mass spread

-       pesticides They are an organic matter that will destroy insects and protect crops

-       genetic engineering/biotechnology- Ex. produce medicine from bacteria and fungi, genetically modifying crops to allow them to survive harsh environments, Gene therapy which is replacing a defective gene with an effective one.

- they use up carbon dioxide (helps control global warming) and release oxygen.

What are the normal microbiota? Where are they normally found? Where should they not be found?

ARE found on the skin, in the oral-nasal cavities, in the respiratory tract, digestive tract, and urogenital tract

NOT found in the blood, CSF, muscle, nervous tissue, or bone

Microbiota prevent growth of pathogens by competing with them for resources and Secrete toxins that inhibit the growth of pathogens.

Bacteria characteristics

Cell type- Prokaryotes.

Peptidoglycan in cell walls.

Binary fission (clone themselves)

For energy they use organic/ inorganic chemicals as well as photosynthesis

Some are pathogenic

Archaea characteristics

cell type- Prokaryotic

Lack peptidoglycan in cell walls

Live in harsh environments

Eukarya characteristics

Plants and animals (multicellular), protists such as fungi (single cell organisms), organized cell

Virus characteristics

Acellular.

Consist of DNA or RNA core.

Core is surrounded by a protein coat.

Coat may be enclosed in a lipid envelope.

Viruses are replicated only when they are in a living host cell.

Prokaryotic and eukaryotic cells both have…

plasma membrane and cytoplasm, chromosome(s), enzymes and are made if DNA. Ribosomes is the site of protein synthesis. Produce ATP as their energy source.

viruses differ from pro/ euk. cells because…

They are acellular (non cellular) and have no plasma membrane or cytoplasm. Made of either RNA OR DNA .Chromosome in protein sac. No ATP production

What are prions

Broken/ misfolded (infectious) proteins. Acellular (non cellular)

When was the “golden age of microbiology”?

19th – 20th centuries (1857-1914).

The timeline…

1590- Janssen develops the compound microscope.

1665- Robert Hooke reported that living things were composed of “little boxes” or cells.

1673- The first microbes were observed by Antoni van Leeuwenhoek

Ignaz Semmelweis advocated that doctors should wash their hands to

prevent transmission of disease

1796- Edward Jenner performs the first vaccinations against smallpox

1857- Pasteur discovered fermentation and then pasteurization (application of a

high heat for a short time to kill bacteria)

1858- Rudolf Virchow develops the Cell Theory

1861- Louis Pasteur provides the final disproof of the theory of spontaneous

1867- Joseph Lister used a chemical disinfectant after learning about pasteur’s findings

1881- Koch develops the technique of streaking for isolation on solid media

1892-Sergei Winogradsky develops the idea of microorganisms being

involved in biogeochemical cycles.

1928- Alexander Fleming discovered the first antibiotic.

1953- Watson and Crick developed the 3D model of the structure of DNA.

What is spontaneous generation?

The theory that living organisms arise from nonliving matter

What is Biogenesis?

The theory that living organisms arise from preexisting life

What is an infectious disease?

Occurs when a pathogen microbe overcomes the host’s resistance, disease results.

What is an emerging infectious disease (EID)? What contributing factors lead to the appearance of EIDs?

New or changing diseases that are increasing or have the potential to increase in incidence. They exists due to microbial adaptation/mutation, global human travel,

humans moving into previously uninhabited locations, and global climate change.

What categories of microbes cause EID’s? Give some examples of an EID (NOTE: you do not need to name the microbes causing the disease – just the disease name)?

Caused by ANY category of microbe - virus, a bacterium, a fungus, a protozoan, a

helminth, a prion

Lyme disease, coronavirus, West Nile Virus

What is meant by the phrase “phylogenetic hierarchy?

What is “scientific nomenclature”?

Used to name microorganisms

How to write organism names using binomial nomenclature

The genus name (captiatized) and the specific epithet (lowercase).

Always underline or italicize names!

What is meant by the phrase “taxonomic hierarchy”?

Used to classify living organisms from broadest to most specific

What is the hierarchical order of the taxonomic subdivisions?

Domain, Kingdom, Phylum (Division), Class, Order, Family, Genus, Species.

How are prokaryotes classified?

Bacteria and Archaea

How are eukaryotes classified?

a. What are the four eukaryotic kingdoms?

i. What are the basic characteristics of each?

ii. What are some organisms found in each?

How are viruses classified?