C-1 Flashcards
5 characteristics of living organisms
- maintain a stable environment (cell is a basic unit of life)
- metabolism: capture, utilize, store energy (eat)
- metabolism: synthesis of macromolecule (grow)
- contain, express, and replicate genetic information (replicate)
- adapt to changes in the environment
why are viruses not considered living organisms?
they are not made of cells; can’t keep themselves in a stable state, grow, or make their own energy
Name the first person to observe microbes (the father of microbiology) and describe how this was done
Antonie van Leeuwenhoek kept refining microscope lenses for stronger magnification to see the microbes
spontaneous generation
microbes grow spontaneously without preexisting cells
who supported spontaneous generation?
John Needham (boiled gravy with corks without sealing first flask)
who rebutted spontaneous generation?
- Francesco Redi (left meat in open jar, sealed with cork, and topped with mesh to see maggots grow)
- Lazzaro Spallanzani (boiled gravy in sealed flask first and kept sealed)
- Louis Pasteur (swan neck flask)
swan neck flask
Allowed for boiling without sealing. The top was allowed open for air movement, but the curve in the neck stopped microbes in the environment from getting in the broth
germ theory of disease
most infectious diseases are caused by living organisms like microbes - developed to state that germs (microbes) can cause disease
Robert Koch’s experiment to test the germ theory of disease
states that microorganisms are responsible for disease - created solid agar medium to grow microbes - did postulates to isolate microbes
what are exceptions to Robert Koch’s postulates
- microbes not growing in specific environment
- mice sick but not showing symptoms
- mice infected and not showing same symptoms or getting sick
- many similar exceptions
why solid agar medium is critical in developing the postulates
growing microbes on liquid could affect the microbe or what needs to be isolated to test - a solid surface helps to isolate those microbes
magnification
increases the viewable image size compared to the original size of the organism
resolution
the ability to distinguish that two organisms are separate and observe details
contrast
the ability to distinguish two organisms from a background using shading
bacteria size
1 micrometer
Protozoa size
100 micrometers
virus size
100 nanometers
light microscopy
brightfield
dark field
phase
fluorescent
electron microscopy
TEM
SEM
brightfield
visible light
white background
stain contrast
dead specimen
1000X
dark field
visible light
black background
white specimen (b/w)
live specimen
1000X
phase
- visible light
- 3D
- potentially live specimen
- grey background- darker contrast and white outline
- 1000X
fluorescent
UV light
black background
neon specimen
1500X
TEM (Transmission electron microscopy)
dead specimen
2D slice
b/w
grey
50,000,000X
SEM (Scanning electron microscopy)
dead specimen
3D
outside of specimen
fake color - artificial - b/w
3,000,000X
what was Antoni van Leeuwenhoek’s experiment?
Used a simple microscope (one glass lens and light) to observe microbes
what was Antoni van leeuwenhoek’s conclusion?
There are very tiny (wee beasties)
organisms that can only be seen with a microscope (microbes!)
Francesco Redi’s experiment
Sealed a flask containing meat with cork and gauze and noticed maggots did not spontaneously appear
Francesco Redi’s conclusion
First person to question the theory of
spontaneous generation
John Needham’s experiment
Boiled broth and sealed with a cork – noticed microbes could grow inside the broth
John Needham’s conclusion
Spontaneous generation is true?
Lazzaro Spallanzani’s experiment
Repeated Needham’s experiment, but boiled his broth longer and didn’t use a cork, but melted the flask
closed – did not observe microbial growth
Lazzaro Spallanzani’s conclusion
Spontaneous generation is false –
Needham must not have boiled his
infusions as long, or his cork was
contaminated
Louis Pasteur’s experiment
Developed a swan neck flask to allow air into his boiled infusion while trapping matter from the air in the neck – did not observe growth in his flask
Louis Pasteur’s conclusion
Spontaneous generation is false – air
alone cannot generate microbes; it must come from dust
Robert Koch’s experiment
Developed solid agar medium - allows us to isolate microbes and grow them in pure culture; used this to develop his postulates to prove the germ theory of disease
Robert Koch’s conclusion
Disease is caused by specific
microorganisms
