Midterm Flashcards
What is the biological function of an endospore?
They enable organisms to endure extremes of temperature, drying, and nutrient depletion.
What makes up the mass of a gram positive bacterium’s cell wall?
peptidoglycan
Explain the process of gram staining
- Flood with crystal violet to stain cells purple
- Add iodine sol’n - cells remain purple
- Decolorize with alcohol - gram negative cell become colorless, gram positives remain purple
- Counterstain with safranin - gram negatives turn red, gram positives still purple
When does endospore formation commence?
When growth ceases due to a limitation in availability of some essential nutrient
shape of Spirochaeta
coiled
shape of staphaloccus
spherical
What lens do the lectron and the light microscope not share?
Which lenses do they share?
projector
condensor lens / objective lens
what happens to electron that pass through an electron microscope?
they are either refracted and reflected or absorbed by the specimen
Scanning electron microscope vs transmission electron microscope
Scanning produces a 3d image of the exterior of the cell // Transmission produces a 2d image of a slice of the inside of the cell.
Three main components of flagella
Basal body, hook, filament
The lipids in the cytoplasmic membrane of Bacteria and ________ contain ester linkages, while the cytoplasmic membrane of ________ contain ether linkages.
Eukarya / Archaea
Robert Hooke:
- Discovery of the microscope
- First to describe microbes
Antoni can Leeuwenhoek
- First to describe bacteria
- Microscope designed for do thread counts
- Found that microbes gave rise to other microbes and disproved spontaneous growth
Edward Jenner: First Concepts in Immunity
- Theory that exposure to cowpox provided immunity to small pox
- Exposed youth healthy boy to cowpox resulting in a mild form of the disease but no sickness.
- Introduced the concent of immunity and host defense
- Beginning of vaccinations
Pasteur and Spontaneous Generation
- Discovered that alcohol fermentation was biologically mediated
- Disproved theory of spontaneous generation
- Led to development of methods for controlling growth of microorganisms
- Developed vaccines for anthrax, cholera and rabies
Pasteur’s experiment disproving spontaneous generation
- Swan neck flask experiment
- Pulled out neck
- Purified liquid
- Slowly cooled liquid stayed sterile
- Tipped flask that is contaminated allowed liquid to go bad.
Koch: Infections disease
- Showled link bt microbes and infectious disease
- Identified causative agents of anthrax and tuberculosis.
- Kock’s postulates
- The standards for identifying microbes that cause disease for a long time
- Observe blood/tissue from diseased specimen.
- Identify possible cause
- Innoculate healthy specimen with diseased blood
- See if it gets sick
- Worked out how to grow cells (solid media, saw colonies of cells of diff shapes colours and sizes)
Elie Metchnikoff
- First to describe phagocytes
- Noticed that some cells would “eat” other smaller ones
- Led to initial discovery of the immune system
- Robert Hooke (1635–1703):
- Antoni van Leeuwenhoek (1632–1723):
- Edward Jenner (1749-1823):
- Ferdinand Cohn (1828–1898):
- Louis Pasteur (1822–1895):
- Robert Koch (1843–1910):
- Paul Ehrlich (1878):
- Élie Metchnikoff (1882):
- Robert Hooke (1635–1703): described microbes
- Antoni van Leeuwenhoek (1632–1723): described bacteria
- Edward Jenner (1749-1823): immunity
- Ferdinand Cohn (1828–1898): founded the field of bacterial classification and discovered bacterial endospores
- Louis Pasteur (1822–1895): disproved spontaneous generation
- Robert Koch (1843–1910): microbes cause infectious disease
- Paul Ehrlich (1878): mast cells, blood cell types
- Élie Metchnikoff (1882): phagocytes, innate immunity
- Frederick Griffith (1928):
- Alexander Fleming (1929)
- Oswald Avery, Colin MacLeod, Maclyn McCarty (1944):
- James Watson & Francis Crick (1953)
- Frederick Sanger (1977)
- Frederick Griffith (1928): “the transforming principle”
- DNA that is responsible for genetic info
- Alexander Fleming (1929) antibacterial penicillin
- Oswald Avery, Colin MacLeod, Maclyn McCarty (1944): DNA is the hereditary material of bacteria
- James Watson & Francis Crick (1953) structure of DNA
- Frederick Sanger (1977) dideoxy-sequencing of DNA
- Designed a way of sequencing DNA that is still used today
Frederick Sanger
- Developed DNA sequencing
- First to sequence complete bacteriophage DNA genome
Michael Smith
- Site-directed mutagenesis
- Specific alteration of the nucleic acid sequence within a fragment of DNA
- Figured out how to direct changes in DNA to code for diff proteins
Kary Mullis
- Developed Polymerase chain reaction (PCR)
- Discovered polymerase - able to withstand temperature chainges that occur throughout denatureation, annealing and extension
Barry Marshall and Robin Warren
- Discovered that bacterium (H. pylori) responsible peptic ulcer disease and some form of stomach cancer
- Bacterium is a normal flora in humans, only recently started causing problems.