Exam 1 Flashcards
Who invented the simple (one lens) microscope?
Leeuwenhoek - discovered microbial world
What are the types of microbes? What type of microbe cannot be seen with a regular microscope?
Algae, prokaryotes, fungi, protozoa, viruses, helminths
Viruses require electron microscopes
Contrast biogenesis and spontaneous generation
Biogenesis - life arises from life
Spontaneous generation - life arises from non-life
What was Needham’s experiment and what did it support?
Boiled gravy and sealed the container. The clear broth turned cloudy - supported spontaneous gen
What was Spallanszi’s experiment and what did it support?
Boiled gravy and sealed container - remained clear as long as seal was not broken
conclusions:
Needham failed to boil long/seal well enough
Microbes from air can contaminate experiments
Suggested spontaneous gen was wrong
What was Redi’s experiment and what did it support?
Observed meat decay - maggots only appeared if flies got to the meat - suggested that spon gen was wrong
What was Pastuer’s experiment for spontaneous generation? What special flask did he use?
Spallanzi’s exp + swan neck flasks
Allowed the broth to have access to air but not the dust - used to defy theory of air being needed for “life force”
If broth touched dust, microbes would form
What were the control and experimental variables in Pastuer’s experiment?
Control variable - allowing gravy to have access to air but not the dust - provided “life force”
Experimental - tilt flask to make gravy touch dust - provided needed contact for microbes to grow
Describe the steps of the scientific method. What is a control group?
Observations - Question/Hypothesis - Experiment - Accept, reject, modify hypothesis - Develop theory
Control group - same condition expert for variable that experiment is trying to test
How did Pasteur discover pasteurization?
Had an experiment to see if adding bacteria or yeast after boiling juice caused fermentation
Bacteria - acid
Yeast - alcohol
To prevent spoiling of the wine, boil juice then add yeast
What did Buchner discover?
Fermentation does not require living cells - enzymes in cell extract can cause fermentation
Discovered metabolism - chemical reactions that occur in organisms
What is germ theory and who discovered it?
Germ theory of disease: germs (pathogens) can cause disease
Discovered by Koch
What are Koch’s postulates and what do they prove?
Prove relationship between microorganism and disease
- agent must be found in all infected cases, absent in non-infected cases
- agent is isolated and grown outside of host
- agent exposed to healthy, susceptible host causes disease
- agent must be found in all experimental hosts
What did Semmelweis suggest?
handwashing to reduce spread of infection in hospitals
- women had 20x higher mortality rate
- believed med students were carrying “cadaver particles” - forced them to wash their hands - mortality rates decreased
What did Listel discover?
developed aseptic techniques in medical procedures.
spraying wounds, surgical incisions and dressings with a phenol solution reduced post-surgical infections
Who discovered the first “antibiotic”?
Salvarsan found an arsenic derivative used to treat syphilis - killed causative agent but not host
Ehrlich’s “Magic Bullet” - possible to kill specific microbes
What did Edward Jenner discover?
Small pox vaccine
took cowpox scab from milkmaid - ground it up - injected into kid - exposed kid to smallpox - did not contract
What did John Snow discover?
cholera epidemic in London was centralized around public water supply on Broad St
What is epidemiology?
study of occurrence, distribution and spread of disease in populations
Who was the founder of modern nursing/techniques?
Florence Nightingale - introduced antiseptic techniques in nursing practices
What are the 4 major processes that characterize living cells?
Growth - increasing in size
Reproduction - increase in number
Responsiveness - ability to react to environment (not all motile)
Metabolism - controlled chemical reactions in living cells (does not have to be constant)
Describe the basic structure of the prokaryotic cells
Nucleoid - aggregate of large, circular chromosome, no membrane bound nucleus
Cell wall surrounding the cell membrane
No membrane bound organelles
Include bacteria and archaea
What is glycocalyx? What is its purpose?
Polysaccharide containing material outside the cell
- Capsule - thicker layer, protects cell from host defenses (phagocytosis), pathogenic - makes harder for phagocytes to engulf
- Slime Layer - loose, thinner structure that prevents dehydration and can be used for adherence to objects
What is the structure and function of flagella?
Filament - outside of cell, rotates, made of flagellin protein subunit
Hook - connects filament to basal body
Basal body - attachment to cytoplasmic membrane and cell wall
Involved in motility and chemotaxis - movement to/from chemical
What are the flagella varieties?
Single - one flagella o the end
Polar tuft - multiple flagella on one end
Paratrichus - Covers the surface of the cell
Endoflagella - on both ends and spiral tightly around the cell, does not protrude. located between cytoplasmic and outer membrane, corkscrews through medium
Discuss the structure and function of pili.
pili - threadlike projections made of protein pilin
Conjucation - involved in bacterial mating - transfers DNA between bacteria cells through conduction pore
Conjugation is what is bringing us to pre antibiotic era