Exam l Flashcards
What did John Needham’s experiment do to prove spontaneous generation? How was the experiment flawed?
He placed boiled broth in a bottle, sealed it, and left it for a few days to see if there was any bacterial growth. He stated there was growth, proving spontaneous generation. however he did not heat the broth long enough to kill microbes AND left broths unsealed when they were cooling so he was wrong
This physiologist disproved the theory of spontaneous generation by redoing Needham’s experiment without air exposure to the sample.
Lazzaro Spallanzani
Summarize Luis Pasteur Swan Neck Flask experiment?
In order to test if sterile microbial broth produced life, he filled two flasks with broth and bent them to S shapes. The broth was then boiled and once sterile, he broke off the neck of one flask, leaving it exposed to air. Dust fell directly into the broken flask but stayed in the S of the unbroken ones. The broken flask grew cloudily with microbial growth, but the other remained clear. This disproved spontaneous generation
the germ theory of disease states that:
specific diseases are caused by microscopic germs
What was Robert Koch’s impact in microbiology?
Developed 1st scientific method to establishing microbial cause of disease known as “Koch’s Postulates”
List the four criteria of Koch’s postulate.
- A specific organism is always associated with a given disease
- Microorganism can be isolated from a disease animal and grown in a pure culture in a lab
- cultured microbe will cause disease when transferred to a healthy animal
- the same type of microorganism can be isolated from the newly infected animal
Exceptions to Koch’s Postulate are:
1.microbes known to cause disease aren’t cultivated under lab conditions
2. disease caused by several pathogens
3. pathogens that cause several diseases
4. ethics with humans being the only host
viruses
Explain Hershey and Chase Experiments
To find what the genetic material of bacteriophages were, they labeled the protein coated phage with S35 & DNA coated phage with P32. The phages then infected bacteria and were placed into a blender to separate the phages from the bacterial cells. The mix was centrifuged and checked for radioactivity. It found that the pallet from P32 had radioactivity and pallet from S32 did not. This concluded that DNA is the genetic material of the phages
Zoonotic diseases are
infections of animals that can be transmitted to humans. Ex: Lyme Disease, Ebola
Pandemic disease is an
epidemic that spreads worldwide.
Epidemic disease is
one in which the number of cases increases in a community in a short time.
An asymptomatic carrier
harbors the potential disease agent but does not have the disease.
A reservoir is
an animal (including humans) or an environment that normally harbors the pathogen.
Indirect Transmission
Pathogens may spread indirectly through an intermediary, which may be living or nonliving.
Organisms may spread directly from person to person
Direct contact transmission
Horizontal transmission occurs when
the infectious agent is transferred from one person or animal to the next.
The route of transmission from one person or animal to another is called an
infection cycle.
Mortality is the
rate of death due to a disease
Morbidity is the
rate of illness due to a disease.
microbe (or microorganism)
a living organism that requires a microscope to be seen.
cell
smallest unit of life composed of membrane enclosed compartments
microbes can be classified as members of a
species
genome
genomic DNA of an organism
The collection of all microbes on the human body is called
the human microbiota.
