Module 01 - Introduction to Microbial Cells Flashcards
Define “spontaneous generation”
life can arise from nonliving matter
How did Francesco Redi test spontaneous generation?
- performed an experiment on the notion of spontaneous generation
- refute the idea of spontaneous generation that maggots can spontaneously generate from meat left in open air
- 6 containers - 2 open to air, 2 covered with gauze, and 2 completely closed
- maggots formed only to the jar that was left completely open, this was because of the presence of flies on the meat, causing maggots to form
How did John Needham test spontaneous generation?
- boiled broth of animal and plant matter to kill preexsiting microbes
- broth became cloudy (sealed jars)
- microbes were still in the broth
- argued that the microbes had arised spontaneously
- reality: he didnt boil the broth enough to kill the microbes
How did Lazzaro Spallanzani test spontaneous generation?
- didn’t agree with Needhams results
- performed same experiment as Needham but with many different jars
- used sealed and unsealed jars
- heated but sealed flasks clear with no sign of spontaneous generation, unless the jars were left open
- microbes were introduced to the jars from the air
Microbe
a microorganism, especially a bacterium causing disease or fermentation.
Louis Pasteur - spontaneous generation
- flasks were able to exchange air from outside
- bends and twists in the flask wouldn’t allow for air to come in, unless broken
- airborne microorganisms allow microbes to grow in the broth
- “life is a germ and germ is life”
- boiling the broth kills the microorganisms
Cell Theory
is a scientific theory first formulated in the mid-nineteenth century, that living organisms are made up of cells, that they are the basic structural/organizational unit of all organisms, and that all cells come from pre-existing cells
Two basic tenets of cell theory
- all cells only come from other cells (principle of biogensis)
- cells are a fundamental units of organisms
Endosymbiotic Theory
is the leading evolutionary theory of the origin of eukaryotic cells from prokaryotic organisms (symbiogenesis)
- defined as the theory that mitochondria and chloroplasts arose as a result of prokaryotic cells establishing a symbiotic relationship within a eukaryotic host
Germ theory of disease
diseased may result from microbial infection
Distinguish characteristics of prokaryotic cells
- smaller than eukaryotic cells
- have no nucleus
- lack organelles
- singular, circular chromosome in the nucleiod
- classified as Archaea and Bacteria
- lack membrane bound organelles, inclusions to compartmentalize for cytoplasm
Organelles in prokaryotic cells
plasma membrane, cell wall, capsule, cytoplasm, ribosome, nucleiod, inclusion, plasmid, pilus, and flagellum
Cell Wall
envelopes the cell membrane protecting the cell from osmotic pressure
protects cell from harsh conditions in outside environment, main component of cell wall - peptidoglycan
isotonic membrane
solute concentration inside and outside of cell are equal, not net movement of water
hypertonic medium
solute concentration outside cell is more than inside, water diffuses out of cell
hypotonic medium
solute concentration inside cell is higher than outside, water moves by osmosis into cell (cell can swell and burst)
Crenation
cell can become dehydrated in hypertonic environment
plasmolysis
(cell with cell wall) plasma membrane contracts and detaches from cell wall for shape
Nucleoid
prokaryotic DNA and DNA proteins, DNA interacts with nucleiod - associated proteins (NAPs)
plasmids
extrachromosomal DNA found, plasmids found in bacteria
ribosomes
constructed of proteins and rRNA, found in cytoplasm
inclusion
store excess nutrients in cytoplasmic structures (ex. glycogen, starches and polyhydroxybutyhate)
endospores
bacteria cells are observed as vegetative cells, bacteria can form endospores
a dormant, tough, and non-reproductive structure produced by certain bacteria
plasma membrane
eukaryotic and prokaryotic cells have a plasma membrane
he membrane found in all cells that separates the interior of the cell from the outside environment
flagella
structures to move in aqueous environment
eukaryotic cells
are organisms whose cells have a nucleus enclosed within a nuclear envelope. They belong to the group of organisms Eukaryota or Eukarya
nucleus
complex nuclear membrane that houses the DNA genome
nucleolous
region in the nucleus where RNA occurs, assembly of ribosomes occur
ribosomes
eurkaryotes are 80S ribosomes (40S small subunit and 60S large subunit)
- ribosomes are defined by location: free ribosomes and membrane bound ribosomes
- free ribosomes in cytoplasm
- membrane bound ribosomes attached to rough ER
endomembrane system
unique to eukaryotes, several organelles and connections between them (ER, golgi, lysosomes, vesicles)
endoplasmic reticulum
rough ER is studded with ribosomes bound on cytoplasmic side of membrane, smooth ER has no ribosomes (appears smooth)
golgi apparatus
series of membranous disks, single lipid bilayer that are stacked together
lysosomes
membrane-bound organelles, used to breakdown food, damaged organelles or cellular debirs
peroxisomes
independent from cytoplasm from perchin proteins
cytoskeleton
internal cytoskeleton made of microfilaments, intermediate filaments and microtubules
centrosomes
(mitotic spindles) microtubule-organizing centres, at end of cells
centrioles
(pairs) right angles of each other, each centriole of nine parrallel microtubules arranged in triplets
mitochondria
powerhouse of the cell - gives energy to cell
mitochondrial matrix
location of original bacteriums cytoplasm, and current location of metabolic enzymes, contains mitochondrial DNA and 70S ribosomes
chloroplasts
photosynthesis occurs, three systems: outer membrane, inner membrane and thylakoid membrane system
stroma
(gel like fluid that makes up the volume)
endocytosis
plasma membrane invagination and vacuole vesciles formation
phagocytosis
engulfing of large particles I”cell eating”)
pinocytosis
other type of endocytosis (“cell drinking”)
receptor-mediated endocystosis
type of endocytosis ligards bind to surface receptors on membrane
extracellular matrix
eukaryotic cells that dont have cell walls have the matrix, A large network of proteins and other molecules that surround, support, and give structure to cells and tissues in the body. The extracellular matrix helps cells attach to, and communicate with, nearby cells, and plays an important role in cell growth, cell movement, and other cell functions.
flagella in eukaryotes
locomoiton, very distinct compared to prokayotes
cilia
unique to eukaryotes, covers entire surface of cell
Similarities of Eukaryotes and Prokaryotes
cell membrane, cytoplasm, genetic material for DNA and ribosomes
Differences between Eukaryotes and Prokaryotes
eukaryotes have membrane-bound nucleus, prokaryotes dont
Unique examples of prokaryotes in various habitats on earth
found in hot springs, antarctic ice shield under extreme conditions
Community
group of interacting population of organisms
cooperative interactions
(part of population) benefit populations
competitive interactions
a population competes with another for resources
microbial ecology
study of interactions between microbial populations and environments
symbiosis
interaction between different species that are associated with each other in a community
mutualism
(syntropy, crossfeeding) two species benefit from each other
Amensalism
one population that harms another but is unaffected
- substances that kills other species of bacteria
commensalism
one organism benefits while the other is unaffected
- ex. bacteria can live on our skin, but we remain unaffected/dont react
neutralism
neither symbiotic organism is affected
- ex. active bacteria and endospores
parasitism
one organism benefits while harming another
microbiomes
all prokaryotic and eukaryotic microorganisms and genetic material associated to an organism or environment
resident microbiota
microorganisms that live in/on our bodies
transient microbiota
microorganisms that are temporarily found in human body (pathogenic microorganisms)
how are prokaryotes classified by microbiologists?
based on shape, staining patterns, biochemical or physiological differences
- nucleotide sequences in genes
- staining patterns are based on cell walls
algae
autotrophic prostists that can be unicellular/mutlicellular, algae are sources of agar, agarose and carrageenan, algae uses toxins
lichen
combinations of two organisms , a green alga, or cyanobacterium and fungus, living in a symbiotic relationship
epiphytes
lichen can be found on most surfaces or grow on other plants
cortex
body called a thallus, an outer, tightly packed fungal layer
medulla
inner, loosely packed fungal layer
mizines
hyphal bundles
why are viruses acellular?
because they are not considered alive
