microbes lecture 1 Flashcards
▪ 1347: Plague/”Black Death”: caused by
Yersinia pestis (bacterium).
▪ Robert Koch: proved
bacteria cause diseases
Koch’s postulates 4:
1.Respective microorganism present in sick individuals,
not healthy.
- Isolate and grow in a pure culture.
3.Inoculate into a healthy host – same disease should
occur.
- Re-isolate the same organism from the new diseased
host
discovered penicillin?
▪ Alexander Fleming
Fannie Hesse:
use of agar instead of gelatine.
who led to the use of agar instead of gelatine.
Fannie Hesse
petri dish discoverer
▪ Richard Petri
6 general characteristics of microbes
- diverse in size, microscopic
- less complex than animals and plants
- rapid growth rates
- ubiquitous, abundant
- NB role in cycling of nutrients and functioning ecosystems
- diverse metabolic pathways
- metabolites used in medicine
during decomposition of biological material what is released back into the environment by decomposers
C, N, S, P, etc
what do denitrifers do
when organisms that contain N die, they return the N to the atmosphere completing the cycle
certain prokaryotes convert N2 to what
for what?
Ammonia NH3
For building amino acids, DNA and other N containing molecules
taxonomy hierarchy names
Dear King Philip Cried Out For Goodness Sake Domain Kingdom Phylum Class Order Family Genus Species
def of type strain
one strain of a species, usually the one which the most representative of the species
Domain Eukarya includes what kingdoms
- Fungi
- Animalia
- Plantae
- Protista
What domains are chemoheterotroph
fungi and animalia
what domain is a photoautotroph
plantae
evolution of Eukarya from prokaryotes involved 2 primary processes
- membranous organelle: ER, nuclear membrane, golgi apparatus, lysosomes & vacuoles etc.
- infolding of the plasma membrane - Mitochondria 1st, Chloroplast 2nd:
- small prokaryotes established residence inside larger ones via endosymbiosis, deriving their outer membrane from plasma membrane of host cell
- evolved interdependent relationship
- Mitochondria= heterotrophic prokaryotes that had a great efficiency for aerobic respiration
- Chloroplast= photosynthetic autotrophs
which domain is the most primitive
archaebacteria
Domain archae’s gene translation relates more to which domain and why
Eukarya
-Some genes have introns, which is completely absent in bacteria
evolutionary relationship of the 3 domains
both Bacteria and Archaebacteria descended from a common ancestor and then Eukarya later split from Archaebacteria
4 similarities of prokaryotes and eukaryotes
- contain DNA as genetic material
- cytoplasm is membrane bound
- use ribosomes for protein synthesis
- similar metabolic processes
describe the bright-field microscope
- light microscope
- eyepiece with 10x magnifying power
- 3 objective lenses: 10x, 40x, 100x
How does a light microscope work
- light rays pass through the specimen
- the objective and eyepiece lenses magnify the image
why is it called a light microscope
light is passed through the specimen into our eyes
what does a electron microscope use and what are the 2 types
- electron bean
1. SEM-scaning= e-s emitted from object’s surface
2. TEM-transmission= e-s pass through specimen, useful in studying internal organelles/virus particles
EM has a higher resolution than light…what does this mean
the minimum distance between 2 points in a specimen can still be separated and seen as 2 pointd
why are e- suitable radiation from microscope? 2
- short wavelengh, therefore higher resolution
2. negative charge, easily focused using a electromagnet
3 disadvantages of EM
1, specimen must be in a vacuum (otherwise air molecules would collide with e-=blurry image)
- specimen must be dehydrated
- only dead organisms can be examined
