Introduction To Microbiology

Front 1

microbe

Back 1

-microorganism or microscopic organism that cannot be seen with the naked eye

-only with a microscope

Front 2

basic research vs applied microbiology

Back 2

1. basic research microbiology: study and classification of microbes/microbial processes/diseases

-subfields: taxonomy, bacteriology, mycology, phycology, virology, etc

-provides foundations for applied microbiology

2. applied microbiology: applying basic understanding of microbial processes and interactions

-subfields: infection control, chemotherapy, pharmaceuticals, genetic engineering, etc

-antibiotics

Front 3

microbial diversity

Back 3

-more abundant than any other living organism

-more diverse than plants/animals

-found anywhere on earth with living water (why NASA looks for planets with water - microbes symbiotic with organisms)

-primary producers (produce organic biomass from inorganic compounds)

-cycle materials from inorganic to organic or organic to inorganic

Front 4

infectious diseases

Back 4

-when microbes grow and multiply after entering the body

-most microbes do not cause disease⭐️

-20th century = switch from infectious diseases to heart disease/cancer/stroke being the top three causes of death in the U.S. - due to antibiotics/vaccines/government controlling sewage tmt

-still influenza/pneumonia/septicimia/etc are top 10

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Aristotle

Back 5

-spontaneous generation: living things arising from non-living (dead meat produces maggots)

Front 6

Pasteur

Back 6

-disproved spontaneous generation

-swan-neck flask experiment: with swan neck no microbes appear in sterilized broth, without neck microbes do appear in sterilized broth

-germ theory of disease: microbes come from envmt, do not spontaneously arise

-Pasteur also worked on fermentation (yeast turning sugar to ethanol), pasteurization (eliminating organisms from wine), and vaccinations (rabies and others)

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Hooke

Back 7

-coined term "cells"

-said all organisms are made of

cells

Front 8

van Leeuwenhoek

Back 8

-invented first microscope

-first person to visualize microbe

-(wasn't even a scientist, was a merchant examining fibers of cloths)

Front 9

Jenner

Back 9

-first vaccine (smallpox)

-noticed milk maids didn't get the disease because exposure to cowpox gave immunity

-involuted a young boy with cowpox, waited, then injected with smallpox

-first disease to be eradicated (late 1970s)

Front 10

Semmelweis

Back 10

-advocated hand-washing (single most important way to avoid infectious diseases)

-women more likely to die in hospital than at home during childbirth - because physicians didn't wash hands and spread disease from patient to patient

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Metchnikoff

Back 11

-discovered phagocytic cells (cells than engulf other cells)

Front 12

Snow

Back 12

-began epidemiology: investigating how diseases spread

-showed how cholera spreads in contaminated water supply

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Koch

Back 13

-stated Koch's postulates: criteria to establish causal relationship between microbe and disease

-also stated one microbe one disease idea: every disease is caused by one microbe (not always true; some are polymicrobial)

Front 14

Gram

Back 14

-invented Gram stain to differentiate G+/- bacteria

Front 15

Lister

Back 15

-invented aseptic techniques in surgery

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Ehrlich

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-pharmacist who created "magic bullets" for disease - mixing and matching chemicals that selectively kill disease without harming human cells

-developed Salvarsan to treat syphilis

-his approach is being used today - personalized medicine is the future of medicine - patients will get specific mix ifnchemicals in appropriate amounts for their condition/body

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Fleming

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-discovered first antibiotic (penicillin)

Front 18

Griffith

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-discovered genetic transformations: process by which bacteria can take up "naked" DNA from environment

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Watson & Crick

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-discovered and described the structure of DNA

Front 20

tree of life

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-all living things evolved from a common unicellular prokaryotic ancestor

-diversified into three domains: Bacteria, Archaea, Eukarya

-scientists look at ribosomal RNA to make evolutionary tree

-three domains replaced five kingdoms: Monera, Protista, Fungi, Plantae, and Animalia - all prokaryotes were grouped in Monera

-viruses aren't in any kingdoms/domains because nonliving and acellular

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hallmarks of cells

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1. cell membrane: defines cell boundaries and controls flow of chemicals in/out

2. genetic material: DNA organized into one or more chromosomes

-some cells have extrachromosomal DNA (DNA in plasmids, mitochondrial DNA, or chloroplast DNA)

-we focus on plasmids

3. self-replication: all cells can multiply and divide on their own

4. regulation: regulate flow of chemicals across membranes

5. similar macromolecules: proteins/lipids/polysaccharides/nucleic acids, typically polymers (lipids aren't true polymers though)

6. energy use: all require energy

Front 22

early life

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-microbes were first life forms

-simple organic molecules (like amino acids) can be formed from inorganic molecules

-bya: earth began to cool, first organic molecules formed, became more complex, formed first cells, then bacteria/archaea/eukarya

-first life forms had genetic code of RNA instead of DNA

-archaea: do not cause diseases, good/useful organisms, grow in extreme conditions

-bacteria, archaea, and eukarya all have common ancestor because genetic similarities

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differences between eukaryotes and prokaryotes

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1. size: eu > pro

2. nucleus: eu = membrane-bound nucleus, pro = nucleoid region

3. membrane-bound organelles: unique to eukaryotes (no organelles in pro/archaea), endosymbiosis (early cell engulfed a prokaryote but didn't digest)

4. DNA differences: eu = linear DNA, pro = circular DNA + plasmids

5. ribosomal differences: (organelles that synthesize proteins) size and composition differs between eu and pro

6. cell wall differences: both eu and pro may or may not have cell walls, eu have chitin and cellulose, bacteria have peptidoglycan/murein (polymer of sugar and amino acids), archaeans have pseudopeptidoglycan/pseudomurein

-most antibiotics break down bacterial cell walls - penicillin interferes with peptidoglycan production, works on bacterial but not fungal infections (fungi don't have peptidoglycan)

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plasmids

Back 24

-small circular bits of "bonus" DNA

-can contain bacterial resistance genes or disease-causing genes

-can be transferred between bacteria (unlike extrachromosomal DNA in mitochondria/chloroplasts)

-provides mechanism for spreading antibiotic resistance (if plasmid has antibiotic resistance gene) or spreading infection (if plasmid has infectious genes)

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viruses

Back 25

-nonliving, acellular

1. lack cell membranes

2. genetic material is often RNA not DNA

3. cannot self-replicate

4. cannot regulate the flow of materials across their membranes (because don't have membranes)

5. cannot use or produce energy

-also smaller than prokaryotic and eukaryotic cells

-called nonliving infectious agents because are obligate intraceullar parasites: cannot grow and reproduce outside of host

-other nonliving infectious agents: prions and viroids (prions cause mad cow disease)