Microbial Nutrition, Ecology and Growth Flashcards
What are essential elements?
elements which are required for life
Macronutrients
nutrient which is required in large amounts
Macronutrients include
phosphorus, hydrogen, oxygen, nitrogen, carbon; main essential elements
Micronutrients
nutrients required in small amounts
Micronutrients aid in…
enzyme function and metabolic reactions
Heterotrophs (source of carbon)
organisms that obtain organic molecules from other organisms; eating sugars, fats, amino acids, etc.
Autotrophs (source of carbon)
make their own organic molecules from inorganic sources
Inorganic sources include
water, carbon dioxide
Carbon fixation
turning inorganic carbon into organic carbon; autotrophs
Nitrogen is mostly found with what bond?
triple covalent bond
Nitrogen fixation
turning nitrogen into NO2, NO3, NH4; nitrite, nitrate, ammonia
How do organisms take up phosphorus?
through the soil
Effect of zinc in organisms
blocks the glycoproteins on our cell surface to prevent the attachment of the glycoprotein spikes on viruses
Microbe consumption types
autotrophs and heterotrophs
Autotrophs
create their own energy using inorganic molecules
Autotrophs include…
photoautotrophs and chemoautotrophs/lithoautotrophs
Photoautotrophs
obtain energy from sunlight and make their own organic molecules
Equation for photosynthesis
6CO2 + 6H2O + sunlight –> 6O2 + C6H12O6
Characteristics of photoautotrophs
create the basis for many food webs, process of photosynthesis is oxygenic, contain chlorophyll a, plants/algae/cyanobacteria undergo photosynthesis
Oxygenic
create oxygen gas
Chemoautotrophs/lithoautotrophs
make their own organic molecules by oxidizing minerals
Chemoautotrophs characteristics
eat rocks, most likely to first evolve, are methanogens
Heterotrophs
obtain their energy from other organisms
Many heterotrophs are…
chemoheterotrophs
Chemoheterotrophs
take chemical energy and convert it into ATP
Aerobic cellular respiration equation
C6H12O6 + 6O2 –> 6CO2 + 6H2O + 36/38 ATP
36 ATP is the amount created for…
eukaryotic cells
38 ATP is the amount created for…
prokaryotic cells
Heterotrophs include…
chemoheterotrophs, saprobes, parasites
Saprobe
eat dead organisms/matter/waste to obtain their energy
How do saprobes consume other organisms?
release enzymes to hydrolyze molecules to become smaller to help transportation
Why are saprobes unable to engulf organisms?
their cell wall
Saprobes can become what kind of pathogens?
facultative and opportunistic
Facultative pathogens
does not want to be a parasite but if the perfect opportunity is there, the microbe will become parasitic
Opportunistic pathogen
if there is a possible chance to become parasitic the microbe will take it
True Parasite
parasites that can cause disease on a healthy individual
Ectoparasite
on surface/outside
Endoparasite
live inside of the body
Intracellular parasite
inside of a cell
Passive transport
uses molecules inherit energy to move it into and out of the cell
Passive transport examples
diffusion, osmosis, facilitated diffusion
How is energy of molecules measured?
temperature/heat
Diffusion
random movement from high to low concentration until reaching dynamic equilibrium in an open space
Brownian motion
random movement from high to low concentration until molecules are evenly dispersed
Dynamic equilibrium
evenly dispersed molecule/matter
Osmosis (living organisms)
movement of water across the membrane
Why is water ideal in osmosis?
water can move freely across the membrane because it is small and uncharged
Cell responses to osmotic varitiaons
isotonic, hypotonic, hypertonic
Isotonic solution
concentration of the cell is equal to the concentration of the solute; solution concentration = cell concentration
Diffusion of water in isotonic solution
equal in both directions into and out of the cell
What organism is always in an isotonic solution?
parasites
Hypotonic solution
concentration of the cell is more than the concentration on the solute/outside of the cell
Diffusion of water in hypotonic solution
more water will enter the cell
Hypotonic solution effect on cells
cell wall: wall become turgid and the cell membrane expands (plants/algae, bacteria, fungi)
no cell wall: lysis; cell explodes (animals, protazoa)
Hypertonic solution
more solute in environment in comparison to the inside of the cell
Diffusion of water in hypotonic environment
more water will leave the cell causing the cell to plasmolyze
Plasmolysis
when the cell shrinks
Hypotonic adaptations
cell wall and protein pumps that pump out water using ATP; freshwater environments
Hypertonic adaptations
cell absorbs salt making themselves isotonic to their environment
Facilitated Diffusion
using proteins (selective channels in the membrane) to allow ions to enter or exit the cell membrane in response to the concentration gradient
Which passive transport method has a maximum rate which molecules can move across the channels?
facilitated diffusion
Active transport
uses energy (ATP) added from the molecule to help move it into and out of the cell against the concentration gradient
Why does active transport require energy?
it is defying the concentration gradient going from low to high
What macromolecule is required to help move molecules in active transport?
proteins
In what instances does active transport occur?
when cell wants to bring in food from the outside to the inside
Types of active transport
pump/ion carrier, group translocation, bulk transport
Pump/ion carriers
pumping ions across the membrane moving them from low to high concentration/across the concentration gradient; can be into and out of cell
Group translocation
coupling together the transport of a molecule with a chemical alteration of the molecule as it moves across the membrane
Group translocation example in microbiology
when using ATP it releases ADP and PO4 which then attaches to glucose to create more ATP
Bulk transport
bring/release many complex molecules at one time
Endocytosis
brining molecules into cell
Ectocytosis
taking molecules out of the cell
How does bulk transport occur?
the plasma membrane covers molecules which creates a vacuole, this is then transported into the cytoplasm (during endocytosis)
Phagocytosis
endocytosis of solids (more common with cells)
Pinocytosis
endocytosis of liquids
When referring to the temperature adaptations of a cell what is it focused on?
what temperature is good for the enzyme, what is their structure, and how do they function
Cardinal range
the range of temperatures which can aid in killing or growing an organism
3 cardinal ranges
minimum, optimal, maximum
Cardinal range: below minimum effect on enzyme
become dormant and are too slow to reproduce
Cardinal range: above maximum effect on enzyme
enzyme denatures and cells die
Cardinal range: optimal
temperature at which they reproduce the fastest
Psychrophile
an organisms that thrives at lower temperatures (15C is optimal but can exist at 0C)
Mesophile
organism that grows well in human body and room temperature (20C-37C)
Thermophile
heat loving microbes; likely first organisms on earth
Toxic oxygen byproducts (most-least toxic)
single oxygen, superoxide ions, peroxide, hydroxyl, oxygen gas
What are the 2 important enzymes aerobes have in order to process toxic oxygen byproducts?
superoxide dismutase, catalase
what does superoxide dismutase do?
superoxide ion –> peroxide + oxygen
what does catalase do?
hydrogen peroxide –> oxygen gas + water
If superoxide dismutase and catalase are not present then the organism is no longer considered…
an aerobe
Types of aerobes
obligate aerobe, faculatative aerobe, microaerophile
Obligate aerobe
require atmospheric oxygen to survive
Faculatative aerobe
organism which prefers atmospheric oxygen, but are capable of surviving oxygen poor environments (typically short periods of time)
Microaerophile
organism that survives under atmospheric levels; just underneath soil/water
Types of anaerobes
obligate and aerotolerant anaerobe
Obligate anaerobe
when exposed to oxygen organisms dies or enters dormant state
Aerotolerant aerobe
tolerate oxygen but are not aerobic
How do aerotolerant aerobes process toxic oxygen byproducts?
use other enzymes that are not catalase/superoxide dismutase to break down oxygen
Symbiotic
interaction between two organisms which is required for at least one organism
Symbiotic relationships include
mutualism, commensalism, parasitism
Mutualism
partners both benefit
Example of mutualism
E. coli and human
Commensalism
one partner benefits while the other is neutral
Example of commensalism
bacteria that lives on skin
Satellite colonies
a different species of microbes which grow around a bigger main colony (frequent with plates that contain antibiotics)
Parasitism
one partner benefits while the other suffers a cost
Example of parasitism
tapeworms, malaria
Non-symbiotic relationships include
synergism, antagonism
Synergism
microbes which benefit each other as they grow together; feeding into each others waste
Example of synergism
nitrogen fixing rhizobium bacteria and bean plants
Antagonism
microbes which fight/kill others in order to gain an advantage
Example of antagonism
antibiotics made by bacteria/fungi in order to kill other bacteria due to competition
Biofilm: Quorum sensing
microbes which are communication with other microbes of the same species about their concentration so when the concentration hits a minimum, they change their behavior which can form a biofilm or the population will become pathogenic
How do microbes undergo quorum sensing?
microbes release inducer molecules at a slow rate and once they build up and are able to sense many inducer molecules it will induce a coordinator response
How is quorum sensing preventable?
medication that destroy inducer molecules
What are the two things microbial growth refers to?
population size or growth size of the organism
What effects the growth size of the cell?
the amount of water in a cell
Binary fission
cell divides into 2 identical daughter cells of equal size in half and DNA is replicated and split between the two cells
What cells undergo binary fission?
most bacterial cells
Exponential growth
population doubles in growth
Doubling time
time span it takes for the population to double from one generation to the next
What if the typical doubling time?
30-60 minutes
Growth curve phases
lag, log, stationary, death
Lag phase
population: no growing
cellular: starting to eat and replicating DNA to get ready to become optimal cell dividers
Log phase
population: growing as fast as it can
cellular: cells are dividing as fast as they can
Stationary phase
population: holding steady; death and birth of cells
cellular: cells are running out of food and cannot divide rapidly
Death phase
population: more dying than reproducing
cellular: cells are dying
What causes the death phase to occur?
accumulation of waste
What can prolong the life span of a cell?
cooler temperatures/refrigeration
Methods of analysing population growth
viable cell count, turbidity of liquid cultures, spectrophotometer, slide cytometer, flow cytometer
Viable cell count
serial dilution of a microbe in a liquid medium
Viable cell count characteristics
fairly accurate, inexpensive, assesment of living cells, wait for results
Turbidity of liquid cultures
measure amount of light which passes through a medium which has been innoculates
Spectrophotometer
machine which measures amount of light which passes through liquid culture which has been innocculated
Turbidity of liquid cultures charateristics
inaccurate, inexpensive, mixture of living and dead cells
Spectrophotometer
machine which measures the amount of light coming through a liquid meadium which has neen innocculated
Spectrophotometer characteristics
inaccurate, fairly inexpensive, immediate results, mixture of living and dead cells
Slide cytometer
slide with laser etched grid which makes it easier to count the number of cells with a microscope
Slide cytometer characteristics
accurate, fairly inexpensive, mixture of living and dead cells, immediate results
Flow cytometer
sends cells through a capillary tube that only allows one cell to pass through, then a laser shines through and measures the density of each cell
Flow cytometer characteristics
highly accurate, expensive, can differentiate between living and dead cells
When are flow cytometers used?
research
Chemostat
keeps the cells in late exponential phase by adding food and removing waste, dead cells, and products
What phase in the population growth curve is prized?
late exponential/log phase
