Block A 1 Flashcards
3 things that microorganisms are involved in
-production of food and drinks
-decomposition of organic matter
-maintenance of earth’s ecosystems
oldest known microorganism and age
fossilised stromatolites
3.5 billion years old
estimated mass of bacteria on earth
5x10^30 grams
where are most of the estimated biomass found
soil and oceans
what is the carbon cycle
decomposition of organic matter releases CO2 through respiration
also plays role in formation of fossil fuels by converting dead plant and animal material into hydrocarbons
what is the nitrogen cycle
convert N2 into forms plants and animals can use, eg ammonia (NH3), nitrite (NO2-), and nitrate (NO3-)
what is the name given to the process used in the nitrogen cycle
nitrogen fixation
essential for growth of plants and survival of many organisms
what is the sulfur cycle
oxidisation of sulfur compounds (eg hydrogen sulphide (H2S)) and conversion into sulfuric acid (H2SO4)
what does the sulfur cycle play a role in
geochemical cycling of sulfur and formation of sulfur minerals
what is the phosphorus cycle
release of phosphate from minerals, an essential nutrient for plants and animals
what does the phosphorus cycle play a role in
formation of bone and teeth
by converting phosphates into hydroxyapatite
what is the iron cycle
oxidisation of iron compounds (ferrous iron) and conversion into ferric iron
what does the iron cycle play a role in
geochemical cycling of iron and the formation of iron minerals
what organism survives at high temps
thermophiles and hyperthermophiles
176°F (80°C) and higher
volcanic hot springs, geysers, and deep sea hydrothermal vents
what organism survives at low temps
psychrophiles
-112°F (-80°C) polar ice, permafrost
what organism survives at high pressures
piezophiles
1800x atmospheric pressure
deep sea hydrothermal vents and subsurface oil reservoirs
what organism survives at high salinities
halophiles
salt flats and salt mines
what organism survives at high radiation
deinococcus radiodurans
nuclear waste sites, space
what organism survives at high acidity
acidophiles
acid mine drainage, acid hot springs, acid soils
why do plants require microbes to survive
microbial symbionts (rhizobia) which live in their roots convert atmospheric N2 into a form that plants can use and is essential for growth of plants (nitrogen fixation)
why do animals require microbes to survive
microorganisms digest their food
eg ruminant microbes break down plant materiak and termite microbes digest wood
why do animals require microbes to survive
microorganisms digest their food
eg ruminant microbes break down plant materiak and termite microbes digest wood
why do humans require microbes to survive
gut microbiome is important for digestion, metabolism, immunity, and production of vitamins and other essential compounds
why does marine life require microbes to survive
responsible for primary production
the process of converting dissolved inorganic compounds into organic compounds, which forms the base of the ocean food web
why does soil require microbes to survive
break down dead plants and animals, releasing nutrients back into soil
help maintain soil structure by forming microbial aggregates that help to retain water and air
structure of prokaryotes
no membrane enclosed organelles
no nucleus
generally smaller than eukaryotic cells
structure of eukaryotes
DNA enclosed in a membrane bound nucleus
cells are generally larger and more complex
contain organelles
eukaryotic DNA
linear and found within nucleus
usually more than one chr
typically 2 copies of each chr
prokaryotic DNA
single circular DNA mol called chromosome
also may have small amounts of extrachromosomal DNA called plasmids (may confer special properties, antibiotic resistance)
what is a genome
a cell’s full complement of genes
E.coli genome compared with the human cell
-e coli
4.64 mil base pairs
4300 genes
-human cell
1000X more DNA per cell than E coli
7X more genes than E.coli
what is metabolism
chemical transformation of nutrients
what is reproduction
generation of two cells from one
what is differentiation
synthesis of new substances or structures that modify the cell (only in some microbes)
what is communication
generation of, and response to, chemical signals (only in some microbes)
what is movement
via self propulsion, many forms in microbes
what is evolution
the process of change over time that results in new varieties and species of organisms
what is phylogeny
evolutionary relationships between organisms
relationships can be deduced by comparing genetic info in the different specimens
relationships visualized on a phylogenetic tree
what type of RNA is excellent for determining phylogeny
rRNA
comparative rRNA sequencing has defined 3 distinct lineages of cells called domains, what are they
bacteria (prokaryotic)
archaea (prokaryotic)
eukarya (eukaryotic)
what 2 are more closely related (bacteria, archaea, or eukarya)
archaea are more closely related to eukarya than bacteria
what are microbial communities
microorganisms exist in nature in populations of interacting assemblages
what does habitat mean
environment in which a microbial population lives in
what is an ecosystem
refers to all living organisms plus physical and chemical constituents of their environment
what is the study of microbial ecology
study of microbes in their natural environment
what is the diversity and abundances of microbes controlled by
resources (nutrients) and environmental conditions (temp, pH, O2)
what can the activities of microbial communities affect
the chemical and physical properties of their habitiats
what are extremophiles and what environments do they grow in
bacteria and archaea
-very hot or very cold
-very acidic or very caustic
-very salty or osmotically stressing
-very high pressure
where are most microbial cells found
oceanic and terrestrial subsurfaces
cells are key reservoirs of what essential nutrients
C, P, N
positive impacts of microorganisms and agriculture
N-fixing bacteria
cellulose degrading microbes in the rumen
regeneration of nutrients in soil and water
negative impacts of microoganisms and agriculture
disease in plants and animals
negative impacts of microorganisms and food
cause food spoilage, methods of preservation are needed
positive impacts of microorganisms and food
fermentation
cheeses, yogurt, buttermilk
beer, leavened breads etc
microorganisms, energy, and the environment
role of microbes in production of biofuels
eg methane, ethanol, hydrogen
role of microbes in cleaning up pollutants (bioremediation)
what did pastuer discover
-living organisms discriminate between optical isomers
-alcoholic fermentation was a biologically mediated process
-theory of spontaneous generation
leading to development of methods for controlling growth of microorganisms
what did koch discover
