Exam #1 Study Guide/Review Flashcards
What are the 3 domains?
Archaea, bacteria, eukaryota
Who supported theory of spontaneous generation?
- Aristotle
- Jan Baptista van Helmont
- John Needham
Who refuted theory of spontaneous generation?
- Francesco Redi
- Louis Pasteur
- Lazzaro Spallanzani
Robert Koch’s 1st postulate
microorganism must be observed in every case of the disease
Robert Koch’s 2nd postulate
microorganism must be isolated & grown in a pure culture
Robert Koch’s 3rd postulate
the pure culture, when inoculated in animals, must reproduce the disease
Robert Koch’s 4th postulate
microorganism must be recovered from diseased animal
Structure & function of fimbriae
- short bristle like proteins projecting from cell surface by the 100s
- enable cell to attach to surfaces and other cells
Structure & function of pili
- longer less numerous protein appendages
- aid in attachment to surfaces
- F pilus (sex pilus) transfers DNA between bacterial cells
Structure & function of flagella
- used to move in aqueous environments
- stiff spiral filaments composed of flagellin protein subunits
- extend outward from cell and spin
- basal body is motor of flagellum and is embedded in plasma membrane
- hook region connects basal body to filament
Host range
most viruses can only infect cells of one or a few species of organisms
tropism
viruses only infect specific hosts and only specific cell types within those hosts
Attachment
virus interacts with specific host cell receptors
Penetration
animal viruses enter thru endocytosis or membrane fusion
Uncoating
viral contents are released
Biosynthesis
viral nucleic acid & proteins are synthesized
Maturation
new mature virions assemble
Release
released by lysis or budding
Hippocrates
- father of western medicine
- didn’t believe that disease was caused by supernatural forces; believed it had natural causes
- Hippocratic oath
Louis Pasteur
- Showed that individual microbe strainshad unique properties
- demonstrated that fermentation is caused by microbes
- invented pasteurization
- Developed vaccines
- performed swan neck flask experiment
Robert Koch
- 1st to demonstrate connection between a single isolated microbe & a known human disease
- discovered bacteria that cause anthrax, cholera, & TB
Franseco Redi
- van Helmont’s contemporary
- performed experiment that refuted idea that maggots spontaneously generate on meat
Jan Baptista van Helmont
- Flemish scientist
- proposed that mice arose from rags & wheat kernels left in open container for 3 weeks
Robert Hooke
While observing cork through his microscope, Hooke saw tiny boxlike cavities, which he illustrated and described as cells. He had discovered plant cells! Hooke’s discovery led to the understanding of cells as the smallest units of life—the foundation of cell theory.
Theodor Schwann
1st concluded that both plants and animals were composed of cells. 2nd, these cells have independent lives. 3rd, these independent lives are subject to the organism’s
Robert Remak
published convincing evidence that cells are derived from other cells as a result of cell division
Rudolf Virchow
finding cells in bone and connective tissue and describing substances such as myelin
Robert Brown
best known for his descriptions of cell nuclei and of the continuous motion of minute particles in solution
Konstantin Mereschkowski
proposed symbiogenesis, or endosymbiotic theory.
Andreas Schimper
- established the fact that starch is both a source of stored energy for plants and a product of photosynthesis
- showed that starch grains are formed within certain bodies of the cells of plants; he named these bodies chloroplasts.
Lynn Margulis
argued that inherited variation, significant in evolution, does not come mainly from random mutations.
Girolamo Fracastoro
early proponent of germ theory of disease
Ignaz Semmelweis
- noted that mothers who gave birth in hospital ward died of puerperal fever after childbirth w/10%-20% mortality rate
- mothers in wards staffed w/midwives had 1% mortality rate
- medical students handled dead tissues & pts w/out washing hands
- recommended hand wash with chlorinated lime water before & after
- mortality rate decreased to 1%
John Snow
- conducted studies to track source of cholera outbreaks in London
- represents 1st known epidemiological study that resulted in public response to epidemic
Joseph Lister
- attempted to determine cause of post surgical infections
- began using carbolic acid (phenol) as disinfectant/antiseptic during surgery
- created aseptic technique
Marcus Terentius Varo
- 1st to propose concept that things we can’t see cause disease
Thucydides
- Father of scientific history
- evidence based analysis of cause & effect reasoning
- made observation during Athenian plague that survivors didn’t get reinfected; immunity
Antone van Leeuwenhoek
- 1st to develop lens powerful enough to view microbes
- was able to observe organisms he called “animalcules”
Carolus Linnaeus
- Most famous early taxonomist
- created categorization above kingdom level
Matthias Schleiden
- cofounded cell theory w/Theodor Schwann
- defined cell as basic unit of plant structure
Dmitri Ivanovski
discovered filterable component smaller than bacterium that caused tobacco mosaic disease (TMD)
Martinus Beijerinck
determined component found by Ivanovski was not a bacterium but more like a chemical
Coccus shape
Round
Bacillus shape
Rod
Vibrio shape
Curved rod
Coccobacillus shape
Short rod
Spirillum shape
Spiral
Spirochete shape
Long, loose, helical spiral
Coccus arrangement
Single coccus
Diplococcus arrangement
Pair of cocci
Tetrad arrangement
Grouping of 4 cocci arranged in square
Streptococcus arrangement
Chain of cocci
Staphylococcus arrangement
Cluster of cocci
Bacillus arrangement
Single rod
Streptobacillus arrangement
Chain of rods
Structure & function of prokaryotic cell wall
- maintains cell shape, protects cell interior, prevents cell from bursting
- composed of peptidoglycan
Structure of prokaryotic ribosomes
- 70S ribosomes
- composed of 30 S & 50S subunit
How are viruses cultivated or cultured?
- in vivo (in a whole living organism, plant, or animal)
- in vitro (outside living organism in cells in an artificial environment)
- cannot survive w/out host
Trichuris trichuria
human whipworm
Borrelia burgdorferi
causes Lyme disease
Piptoporus betulinus
- fungus
- has laxative & antibiotic properties
bacillus anthracis
Bacteria that causes anthrax
Vibrio cholera
Bacteria that causes cholera
mycobacterium tuberculosis
Bacteria that causes tuberculosis
Ernest Haeckel
Proposed kingdom Protista & kingdom Monera
Robert Whittaker
Proposed adding kingdom fungi
Haloquadratum walsbyi
- Genus describes salt water habitat & arrangement of its square cons
- named after Anthony Edward Walsby
Mycobacterium leprae
Causes leprosy
Dracunculus medinensis
- Helminth; guinea worm
- causes dizziness, vomiting, diarrhea, ulcers in legs & feet where worm exits skin
Staphylococcus aureus
- Gram-positive bacterium that consists of clustered cocci cells
- ability to evade antimicrobials, particularly methicillin
E. coli O157:H7
- Causes abd. cramps & diarrhea
- originates from contaminated water or food
Giardia lamblia
- intestinal protozoan parasite that infects humans & other mammals
- causes severe diarrhea
Candida albicans
- unicellular fungus/yeast
- causes vaginal yeast infections, order finish
- morphology similar to coccus bacteria
- eukaryotic organism
Saccharomyces cerevisiae
- yeast
- makes beer, wine, bread
- fermentation yields ethanol & carbon dioxide
Aristotle
earliest recorded scholars to articulate theory of spontaneous generation
John Needham
- believed theory of spontaneous generation
- performed experiment with boiled both infused with plant or animal matter
Lazzaro Spallanzani
- Didn’t agree with Needham’s conclusion
- performed hundreds of experimentswith heated broth with sealed & unsealed flasks
- concluded that “Life force” was killed during Needham’s experiment
Structure of prokaryotic chromosomes
a single circular chromosome located in a nucleoid
Structure of prokaryotic plasmids
small, circular, double stranded DNA molecules
Structures associated with prokaryotic cells
- lack membrane bound organelles
- has cell membrane, chromosomal DNA in nucleoid, ribosomes, cell wall
- some have flagella, pili, fimbriae, capsules, inclusions
- nucleoid associated proteins (NAPs) help package DNA
Structure & function of inclusions
- cytoplasmic structures
- store excess nutrients, glycogen, starches
- magnetosomes, metachromatic granules, gas vacuoles
Structure & function of endospores
- vegetative bacterial cell; dormant state when environmental conditions are unfavorable
- survive long periods w/out food or water
Structure & function of plasma membrane
- phospholipid bilayer embedded w/various proteins
- glycoproteins (carbohydrate w/protein)
- glycolipids (carbohydrate w/lipid)
Structure of peptidoglycan
- composed of long chains of alternating molecules of N-acetylglucosamine (NAG) & N-acetylmuramic acid (NAM)
Acid fast positive cell wall
- external layer of mycolic acids in cell wall
- stains that must stand up to acids used
Structure & function of capsules
- organized firm layer located outside of cell wall
- usually composed of polysaccharides or proteins
Structure & function of slime layers
- less tightly organized layer
- loosely attached to cell wall and more easily washed off
- may be composed of polysaccharides, glycoproteins, glycolipids
How do retroviruses integrate into host genome?
- has enzyme called reverse transcriptase
- reverse transcriptase makes complementary ssDNA (cDNA) copy using +ssRNA genome as template
- ssDNA made into dsDNA
- dsDNA integrates into host chromosome to form provirus
- provirus remains and can cause chronic infection
Virus helical capsid shape
- cylindrical or rod shaped
- genome fits just inside length of capsid
- can be enveloped or naked
Virus polyhedral capsid shape
- consist of nucleic acid surrounded by polyhedral capsid in form of icosahedron
- icosahedral capsid is 3D, 20 sided structure w/12 vertices
- can be enveloped or naked
Virus complex capsid shape
- example: bacteriophages
- genome located w/in polyhedral head
sheath connects to head to tail fibers & tail pins that help virus attach to receptors on host cell surface
Examples of latency & latent viruses
- latent viruses can remain latent or asymptomatic inside cell for extended periods
- herpes simplex virus (oral & genital herpes)
- varicella-zoster virus (chickenpox, shingles)
- Epstein-Barr virus (mononucleosis)
Virions
new virus particles formed from viral components, proteins, nucleic acids synthesized by host cell the virus is inhabiting
Virusoids
- subviral particles; non-self-replicating ssRNAs
- 220-388 nucleotides long
- ## require helper virus like HBV
Prions
- discovered by Stanley Prusiner
- proteinaceous infectious particles
- PrPc + normal; PrPsc = not normal = prion
- transmission occurs from animal to animal, animal to human, eating contaminated meat, heredity, contact with contaminated tissue
- cause transmissible spongiform encephalopathy (TSE)
- include kuru, mad cow disease, scrapie
Structure of virions
capsid encloses genome of either DNA or RNA
Structure of capsids
- surrounds viral genome
- composed of protein subunits called capsomeres that are made of different protein subunits that interlock to form capsid
Robert Koch
- proposed series of postulates based on idea that cause of specific disease could be attributed to specific organism
- Koch & colleague found causes of anthrax, TB, & cholera
Gram-positive cell wall
- Gram-positive cell wall is NAG, NAM, NAG, NAM, etc. cross linked by peptide bridges
- consists of many layers of peptidoglycan 30-100nm in thickness
- peptidoglycan layers embedded w/ teichoic acids (TAs) that extend thru layer
Gram-negative cell wall
- Gram-negative cell wall is NAG, NAM, NAG, NAM, etc. w/direct link
- thin layer of peptidoglycan ~4nm thick
- gel-like matrix occupies periplasmic space between cell wall & plasma membrane
- 2nd lipid bilayer external to peptidoglycan layer called outer membrane that contains lipopolysaccharide (LPS)
- LPS composed of Lipid A, a core polysaccharide, an O side chain
structure & function of glycocalyx
- sugar coat with 2 different types
- capsule & slime layer
- allow cells to adhere to surfaces, aide in formation of biofilms
monotrichous flagella arrangement
a bacterium w/a singular flagellum located at one end of the cell
amphitrichous flagella arrangement
flagellum or tufts of flagella at each end of cell
lophotrichous flagella arrangement
have tuft of flagella at one end of cell
peritrichous flagella arrangement
flagella cover entire surface of cell
H1N1 influenza
- outbreak in 2009
- spread across various continents
Ebola
early 2014 epidemic in western Africa
COVID-19
- began 2019; pandemic
- 4.5mil deaths worldwide
- 640K deaths USA
Edward Jenner
- inoculated pts with cowpox to prevent smallpox
- technique he called vaccination
host specific (host tropism)
viruses only infect certain type of host
tissue tropism
viruses only infect certain types of cells within tissues
steps of lytic cycle
- attachement
- penetration
- biosynthesis
- maturation
- lysis
steps of lysogenic cycle
- attachment
- penetration
- integrates into bacterial chromosome
- becomes integrates prophage
- lysogenic conversion (phage conversion) - change in host phenotype
viroids
- consist of only short strand of circular RNA capable of self replication
- result in devastating losses of food crops