microbiology introduction Flashcards
7 groups of microorganisms
bacteria
archaea
fungi
protozoa
algae
small multicellular animals
viruses(?)
prokaryotic cell
-no nucleus
-no membrane-bound organelles
-circular chromosomes
-asexual reproduction (binary fission)
-unicellular/colonial
-usually small
bacteria
-peptidoglycan cell wall (some species lack cell wall)
-a few species are harmful to humans; most are neutral or beneficial
what is the bacterial cell wall made of?
peptidoglycan
arcaheans
-non-peptidoglycan cell wall
-ribosomal structure closer to eukaryotes
-often found in extreme environments
-none associated with disease
i..e methanogens (animal GI tract), extreme halophiles (super salty environment)
5 eukaryotes
protists
algae
fungi
plants
animals
2 prokaryotes
bacteria
archaea
prokaryotes vs eukaryotes:
organization
size
type of nucleus
DNA
cell movement
membrane bound organelles
organization: usually unicellular vs unicellular, multicellular, colonies
size; smaller vs bigger
type of nucleus: none (its DNA housed in a ‘nucleoid’ region) vs proper nucleus with a double membrane
DNA: usually circular, vs linear chromosomes
cell movement; flagella (flagellin protein) vs cilia, pseudopodia
membrane bound organelles: none vs many
fungi
-absorptive heterotroph
-cell wall made of chitin
-uni or multicellular
-hypae (rods) for bisexual and asexual spores to reproduce
or reproduce by budding cells
what is fungi cell wall made of
chitin
fungi, protozoans, animals, algae :
ingestive heterotroph or absorptive heterotroph or photosynthetic autotroph
fungi- absorptive
protozoans- ingestive
animals- ingestive
algae- photosynthetic autotroph
ingestive vs absorptive heterotrophs
Fungi are absorptive heterotrophs: they secrete digestive enzymes that break down polymers to monomers which are absorbed across the cell wall and cell membrane.
-i.e. absorb pre-digested nutrients
Animals are ingestive heterotrophs: they eat their food and digest it in a compartment within their bodies.
protozoans
NOT PROTISTS
-single cells eukaryotes
-ingestive heterotrophs (like animals)
-often sorted according to motility: cilia, flagellum, pseudopodia
how protozoans can move (3)
cilia, flagellum, pseudopodia
algae
-uni or multicellular eukaryotes
-photosynthetic autotroph
-categorized on the basis of their pigmentation and the composition of their cell walls
-multicellular: seaweed and kelp; no roots; all tissues are photosynthetic
animals
ingestive heterotroph
-adults visible but larvae are microscopic
hippocrates
400BC; link between environment and disease
-Thucydides notes plague survivors cannot get the same disease twice
Robert Hooke (1650s)
founder of cell biology
-introduced the notion that cells were the fundamental unit of life
-coined the term “Cell” due to resemblance of honeycomb cells
who was the founder of cell biology
Robert hooke
who was the founder of microbiology
antonie van leeuwenhoek 1670s
antonie van leeuwenhoek 1670s
founder of microbiology
-first reported existence of most types of microorgansims
antonie van leeuwenhoek discovered what?
protists: any eukaryotic organism that is not an animal, plant or fungus
also vertebral sperm cells
-spermatozoa
-muscle fibers
-RBCs
who discovered protists
antonie van leeuwenhoek
who discovered sperm cells
antonie van leeuwenhoek
carolus linnaeus (1735) founded what
taxonomics: a system for naming species and grouping similar ones togehter
-linnaeus described two groups; plants and animals
who founded taxonomics
carolus linnaeus
what was carol’s linnaeus’ hierarchical (linnaen) classification
7 levels- taxon
-binomial nomenclature: genus, species
species –> genus –> family –> order –> class –> phylum –> kingdom
how did Aristotle think life emerged
from biogenesis or spontaneous generation
-life emerging from non-living matter
what is abiogenesis
spontaneous generation
-life emerging from non-living matter
who put abiogenesis/ spontaneous generation into question and what was the experiment?
Fransisco redi
-flask unsealed vs sealed vs covered with gauze
-piece of meat
-only when flies could get in then maggots would be on meat
was John Needham for or against spontaneous generation; what was his experiment
for
he put clear broth in flask, sealed it, boiled it
-as he explained it “there must be a “life force” that causes inanimate matter to spontaneously come to life because he had heated the vials sufficiently to kill everything”
what experiment disproved spontaneous generation?
Pasteurs swan necked flask experiment
-heated flask, let steam escape from flask and air can move in and out but the dust won’t get in so it remains sterile
no microbes appear
pasteur and fermentation; what causes fermentation, what causes spoiling?
fermentation of grape juice into wine via yeast
spoiling via bacterial microbes
pasteur- pasteurization
pasteurization: heat grape juice just enough to kill most bacteria without ruining the juices taste and other qualities
what was the germ theory of disease and who’s theory was it
pasteur
germ theory: microorganisms are also responsible for disease. each disease is caused by a specific germ (pathogen)
diseases caused by germs are no called infectious diseases
who studied the etiology of infectious disease and how was it done
Robert koch
-simple staining techniques
-first photomicrograph of bacteria
-first photograph of bacteria in diseased tissue
-use Petri dish to hold solid growth media
-transferring bacteria with heat and metal wires
–> agar
koch’s postulates (4)
- the suspected causative agent must be found in every case of the disease and be absent from healthy cases
- the agent must be isolated and grown outside the host
- when the agent is introduced to a healthy, susceptible host, the host must get the disease
- the same agent must be found in the diseased experimental host
prevention of disease
- hand washing (Ignaz Semmelweis)
- antiseptic technique and disinfection (Joseph lister)
- disinfect room and clothes (Florence nightingale)
- John snow: correlated cholera propagation with poor water sanitation led to infection control and epidemiology studies
- variolation- vaccine against smallpox
variolation
- vaccine against smallpox
problem: smallpox
-caused by two viral variants: variola major and variola minor
-die less with minor
-so inject with minor
Jenners vaccine
jenner observed that milkmaids dont get smallpox
injected 8 yr old boy with pus from milkmaids cowpox blisters
inject him w variola major
