chapter 1 Flashcards
microbe
living organism that requires a microscope to be seen. single or multicellular.Have proteins, sugars, and genomes made of nucleic acids
virus
noncellular particle w/ genetic material that takes over metabolism of cell to generate more virus particles.
prokaryotes
cells lacking nucleus. bacteria and archaea
eukaryotes
cells with a nucleus. algae, protists, and fungi
genome
genetic info in organism’s chromosomal dna
microbial capabilities are defined by their
genome sequences
good things about microbes
food (cheese, bread, wine) our body is made of microbes.
bad things about microbes
disease (plague, cholera, tuberculosis). more soldiers died from microbial infections than battle wounds. (medical statistics discovered by Florence Nightingale)
bacterial width range from
0.125 to 80 to 750 micrometers.
average bacteria
1 micrometer wide, 2-4 micrometers long
number of prokaryotes, eukaryotes, and viruses
180,000 (mostly bacteria, fewer archaea), 7,000, 23,000
E. coli and B. fragilis
look very similar, but perform different functions. share 40% of genes.
C. elegans and humans
share 38% of genes.
spontaneous generation
concept where living creatures (such as maggots) could arise spontaneously, without parents.
fermentation
microbes gain energy by converting sugars into alcohol. actually caused by living yeast, a single celled fungus.
autoclave
steam pressure device. sterilized materials.
germ theory of disease
theory that many diseases are caused by microbes.
chain of infection
transmission of a disease
pure culture
culture grown from single “parental” cell
Robert Koch
- Anthrax – demonstrated chain of infection
- Tuberculosis –pure culture techniques
- Determined bacterium that causes tuberculosis
- Koch’s postulates
vaccination
practice of cowpox inoculation. Edward Jenner
immunization
deliberate inoculation with a weakened pathogen
two ways to reduce the effect of a strain
heat or aging
antiseptic
ex chlorine. a chemical that kills microbes
aseptic
environ free of microbes
antibiotic
kills growth of selected microorganisms
we consider viruses as
what do they contain?
“subcellular organisms”
Rna only.
Louis Pasteur
showed that microbes dont grow in liquid until introduced from the outside. made “swan neck” flask, allowing air, but not microbes or dust to get in. no microbe growth, unless the flask was tilted or broken.
winogradsky column
Built ecosystem for microbes to see how they separate into their own habitats
• Mud, organic C source, and inorganic C source
• After exposure to light for several weeks several zones of color develop
photosynthesis
use light to split water and produce oxygen
geochemical cycling
interconversion of inorganic and organic forms of N, S, P, and others. without this, no plants or animals could live.
nitrogen fixation
archaea and bacteria fix nitrogen by reducing it to ammonia (NH3).
biofilms
microbes growing on a solid surface. in human body.
microbiota or microbiome
all microbes associated with human body
Haeckel categorized microbes in a third kind of life-neither animal nor plant- called
Monera.
mitochondria and chloroplasts contain
DNA
transformation
transforming harmless bacteria into a strain capable of killing mice. genetic material=dna
bacterial dna polymerases are used for
polymerase chain reaction (pcr) amplification of dna.
Koch’s postulates
- The microbe is found in all cases of disease but is
absent from healthy individuals
• 2. The microbe is isolated from the diseased host and grown in pure culture.
• 3. When the microbe is introduced into a healthy host (or animal model), the host shows the same disease.
• 4. The same strain of microbe is obtained from the newly diseased host. When cultured, the strain shows the same characteristics as before.
smallpox
infected large fraction of european population
Lady Mary Montagu
introduced practice of smallpox inoculation in Europe
rabies vaccine (Louis Pasteur)
required heat treatments and repeated inoculations
Most microbes don’t grow on typical media
Less than 0.1% of microbial species can be cultured in lab
Carl Woese
three domains of life based on 16S rRNA sequence
•found in all life.
archaea
-Similar in size and shape to bacteria –diff. biochemistry
• Ribosomes more similar to eukaryotes
-Many live in harsh environments
-Have unique membrane lipids
intracellular endosymbiosis
eukaryotes evolved by merging with bacteria to form
composite cells
