unit 1 Flashcards
What are Koch’s first two postulates?
- The suspected agent must be found in every case of the disease and be absent from healthy hosts.
- The suspected agent must be isolated and grown outside the host.
Who demonstrated that hand washing is important to prevent disease
Ignaz Semmelweis
What is the process by which certain cells can take up bacteria and destroy them internally.
Phagocytosis
What is the primary structural component of bacterial cell walls.
Peptidoglycan
Who discovered Penicillin
Alexander Flemming
coined the term “magic bullet” for chemicals that’s selectively kill pathogens
Paul Ehrich
Who established that a vaccine can prevent disease?
Edward Jenner
Briefly compare respirations and photosynthesis
Photosynthesis - uses light, CO2 & water to make sugars
Cellular Respiration - cells transfer electrons from pyruvate to NADH to O2; C02 & lots of ATP then turned into metabolic water
What type of metabolic pathway does respiration represent?
Catabolic Pathway
What type of metabolic pathway does Photosynthesis represent?
Anabolic Pathway
What are Koch’s third and forth postulates?
- When the agent is introduced to a healthy host, the host must get the disease.
- The same agent must be found in the diseased experimental host
Describe general cell and genome characteristics of prokaryotic & eukaryotic microbes
Prokaryotes - no nucleus, small cells, unicellular; haploid, circular, in nucleoid of cytoplasm & in plasmids
Eukaryotes - Have nucleus, large cells, more complex structures; typically diploid, linear, in nucleus, in some fungi & algae
What mediates the transfer of DNA from one cell to another
Pili, also known as conjugation pili (Mating bridge)
What moves in a series of tumbles and runs
Bacteria
What are 2 types of glycocalyces (plural for glycocalyx)and a function often associated with each one?
Capsule’s are firmly attached to the cell surface.
Slime layer is loosely attached to the cell surface, water soluble, also has sticky layers to allow prokaryotes to attach to surfaces.
what are unique structures produced by some bacteria that are a defensive strategy against unfavorable growing conditions
Endospores
what theory states: smaller aerobic prokaryote were ‘captured’ by larger anaerobic prokaryotes and evolved into mitochondria or chloroplasts
Endosymbiotic Theory (Lynn Margulis)
what are Molecular machines with 2 large subunits that translate message RNA into protein
Ribosomes
What type of bacterial cell walls do the following describe: Single cells – cocci; Chains - streptococci;
Clusters - staphylococci; or Cuboidal packets –sarcinae
Spherical cells
what type of transport is the following: osmosis – moves from higher concentration to lower concentration
Passive transport
what type of bacterial cell walls describe the following: Single cells – bacilli; or chains – streptobacilli
Rod-shaped cells
In what way are bacteria and archaea similar?
unicellular, reproduce asexually & small
In what ways do bacteria & archaea differ?
– 1. Bacterial cell walls have peptidoglycan, while
– Archaeal cell walls lack peptidoglycan.
– 2. A lot of bacteria cause disease, but there are
– No Archaea are known that cause disease.
which Eukaryotes have cell walls
Fungi
What main structure of locomotion in protozoa have one or a few long, whip-like extensions that propel the cell (ex. Sperm cell)
flagella
what structure of locomotion in protozoa have numerous short protrusions that beat synchronously to propel the cell
cilia
an explanation that’s as close to the truth as is humanly possible
Scientific Theory
Who is the father of microbiology
Louis Pasteur
Experiment with “swan-necked flasks” showed that as long as the flask remained upright, no microbial growth appeared in the infusion.
Louis Pasteur
2 Positive Controls that Disproved Spontaneous Generation
- When the flask neck was broken, the flasks were cloudy with microbes within a day.
- When the flask was tilted, dust from the bend in the neck seeped back into the flask and made the infusion cloudy with microbes within a day.
which anaerobe is an organisms that can live with or without oxygen
Facultative anaerobe
which anaerobe is a microorganism that cannot tolerate oxygen and uses a final electron acceptor other than oxygen
Obligate anaerobe
the use of heat to kill pathogens and reduce the number of spoilage microorganisms in food and beverages
pasteurization
means the study of the cause of disease
etiology
Hypothesis formulated by Pasteur in 1857 that microorganisms are responsible for disease.
The germ theory of disease
What was the first bacterial pathogen identified, for what disease, and who did the work?
Bacillus anthracis for anthrax; by Robert koch
dissolves in water into a Hydrogen ion (H+) and one or more anion; Measured on pH scale
acid
What type of solution has a very low pH value? A very high pH value?
Low pH is Battery acid at a 0. High pH is Sodium Hydroxide at a 14.
simple sugars such as glucose (monosaccharides), and complex sugars such as peptidoglycan and starch (polysaccharides)
Functions in energy metabolism & cell walls
Carbohydrates
polymers of amino acids (20 naturally occurring)
• Function as enzymes, in cell structures, and in immune responses
Proteins
the network of biochemical reactions and chemical pathways that occur within organisms.
metabolism
what is produced as ATP & primarily NADH
metabolic energy
Waste product in respiration; electron source
H2O
waste product in photosynthesis; electron acceptor
O2
the apparent increase in object size (e.g. 5000X)
– the max is reached when the finest detail an instrument can resolve matches the finest detail the eye can see.
Magnification
the ability to distinguish objects that are close together
Resolution
differences in color intensity between 2 objects or between an object and its background
Contrast
In microscopy, what 2 factors does resolution depend on?
- The wavelength of light
2. Numerical aperture (NA)
– Only reflected light rays (filtered) pass through the specimen
– Good for unstained objects
Dark-field microscopes (dark background)
– Examine living organisms or specimens that would be damaged/altered by fixing them to slides or by staining.
– Good for viewing internal structures
phase microscopes ; Contrast is created because light waves are out of phase
– Absorbed light is re-emitted at a longer wavelength
Fluorescence Microscopy
What are 2 applications of fluorescence microscopy?
- immunofluorescence to identify pathogens
- cell biology to study proteins and organelles
What is a smear and why are they used in microscopy?
– Smear of microorganisms: sample preparation before staining; thin film of culture
– Drying and Fixation - will attach and kill structures
What 3 outcomes are accomplished by drying and fixation when preparing a smear?
(1) attaches organism to slide,
(2) kills the organism, and
(3) stabilizes cell structures
What is a simple stain and give an example? What are 3 uses of a simple stain?
Simple Stains – use a single dye; e.g. crystal violet, safranin.
Good to determine:
• (1) the size, (2) the shape, and (3) the arrangement of cells
what stain uses more than 1 dye
Differential Stain
which gram cell has a thinner cell wall, with outer lipopolysaccharide membrane
Gram negative cells
cationic chromophore (positive charge)* used mostly in micro
Basic Dyes
