micro #7 microbial nutrition

Microbial nutrition

1. Nutrition: a process by which chemical substances ([1]nutrients__) are acquired from the environment and used in cellular activities (have different pathways)
2. All living things require a source of elements such as C, H, O, P, K, N, S, Ca, Fe, Na, Cl


Nutrition: a process by which chemical substances ([1]nutrients__) are acquired from the environment and used in cellular activities, such as metabolism (have different pathways) & growth

essential nutrition/2 subunits

Essential Nutrient: any substances that must be provided to an organism
b. (2)_macronutrients_: Required in relatively large quantities, play principal roles in cell structure and metabolism (ex. organic molecules C, H, O) put back into macromolecules.

principle inorganic reservoirs of element (4)

carbon -----CO2 in air, CO32- in rocks & sediments
Oxygen-----O2 in air, certain oxides & water
Nitrogen----N2 in air, No3-, No2- NH4+ in soil & water
Hydrogen---water, H2 gas, mineral deposits

chemical analysis of E. coli cytoplasm

1. 70% water
2. protein = next largest, need for metabolic pathways (enzymes)
3. Nucleic acids = dan, rna,
4. nitrogen = most in nucleic acids, proteins, AA
5. phosphorus = dna & rna (not phosphilipids b/c talking about cytoplasm)

Sources of essential nutrients: Carbon

1. The majority of carbon compounds involved in normal structure and metabolism of all cells are organic (C,H,O)
ex. organic carbon molecule = glucose
2. Heterotroph: Must obtain C in organic form (nutritionally dependent on other (4) __living things_)

Sources of essential nutrients: Carbon/heterotroph

1. Must obtain C in organic form (nutritionally dependent on other (4) __living things_)
2. common organic element=proteins, carbs, lipids & Nucleic acid
some small enough to be absorbed (monosacch & AA) but many need to be digested by cell

Sources of essential nutrients: Carbon/autotroph

Autotroph: (auto - = self) Uses inorganic (5)__CO2__ as its carbon source (not nutritionally dependent on other living things) thru fixation will produce glucose, frutose, etc

Sources of essential nutrients: Nitrogen

1. Main reservoir- N2 (N-gas) (3 bonds, 3 pairs or 6 electrons)
2. Primary nitrogen source for heterotrophs- (6) _proteins, DNA, RNA & ATP__. (organic)
3. Some bacteria and algae utilize inorganic nitrogenous nutrients (nitrates, nitrogen gas)
4. Small nu


is a compound of nitrogen and hydrogen with the formula NH3. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers.

symbiotic nitrogen fixation

1. Symbiotic nitrogen fixation occurs in plants that harbor nitrogen-fixing bacteria within their tissues. The best-studied example is the association between legumes and bacteria in the genus Rhizobium.
2. Each of these is able to survive independently (

Sources of essential nutrients: oxygen(3)

1. O is a major component of organic compounds
2. Also a common component of inorganic salts
3. O2 makes up (9)_20%_____ of the atmospheric gas

Sources of essential nutrients: sulfur (3)

1. Widely distributed throughout the environment in mineral form
2. Essential component of some vitamins
3. Found in Amino acids- (10) METHIONINE (1st AA in translation)__ & _CYSTEINE_ Very Important. creates bridges in teritiary structure

Sources of essential nutrients: Hydrogen

1. H is a major element in all organic and several inorganic compounds
2. Performs overlapping roles in the biochemistry of cells:
a. Maintaining pH
b. Forming HYDROGEN BONDS between molecules (ex. water, dna) (A-T = 2 H bonds, C-G = 3 H bonds) (a=

Sources of essential nutrients: Phosphorus/(phosphate)

1. Main inorganic source of phosphorus is phosphate (PO43-)
-Derived from phosphoric acid
-Found in rocks and oceanic mineral deposits
2. Phospholipids in cell membranes and coenzymes
3. Where else is it found in living organisms? (12)

other nutrients important in microbial metabolism

1. Potassium- protein synthesis and membrane function
2. Sodium- certain types of cell transport
3. Calcium- stabilizer of cell walls and (13)_endospores_____
4. Magnesium- component of chlorophyll and stabilizer of membranes and ribosomes
5. Iron- import

Growth factors: Essential organic nutrients

1. Growth factor: An organic compound such as an amino acid, nitrogenous base, or vitamin that cannot be (15) _synthesized/manufactured___ by an organism and must be provided as a nutrient
For example, many cells cannot synthesize all 20 amino acids so th

Main determinants of nutritional type

1. Sources of carbon and energy
2. Phototrophs- Microbes that (17)_photosynthesize____
3. Chemotrophs- Microbes that gain energy from (18) ___chemical___ compounds (w/in covalent bonds)
Review: Autotroph vs Heterotroph and terminology on pg 185

Photoautotroph: energy source, carbon source & example

energy source = sunlight
carbon source = CO2
example = algae, plants & cynobacteria

chemoautotroph: energy source, carbon source & example

energy source = simple inorganic chemicals
carbon source = CO2
example = certain bacteria, such as methanogens, deep sea vent bacteria

Autotroph: energy source, carbon source

energy source = nonliving environment
carbon source = CO2

Heterotroph: energy source, carbon source

energy source = other organisms or sunlight
carbon source = organic

Photoheterotroph: energy source, carbon source & example

energy source = sunlight
carbon source = organic
example = purple & green photosynthetic bacteria

chemoheterotroph: energy source, carbon source & example

energy source = metabolic conversion of nutrients from other organisms
carbon source = organic
example = protozoa, fungi, many bacteria, animals

saprobe: energy source, carbon source & example

energy source = metabolizing the organic matter of dead organisms
carbon source = organic
example = fungi, bacteria (decomposers)

parasite: energy source, carbon source & example

energy source = utilizing tissue, fluids of a live host
carbon source = organic
example = various parasites & pathogens, can be bacteria, fungi, protozoa & animals

autotrophs (2) & their energy sources

1. Photoautotrophs
a. Photosynthetic
b. Form the basis for most food (19) _food web___
2. Chemoautotrophs
a. Chemoorganic autotrophs- use (20) _organic (CHO)__ compounds for energy and inorganic compounds as a carbon source
b. Lithoautotrophs- rely totall

Heterotrophs & their energy sources

1. Majority are (24)_chemoheterotrophs__ that derive both carbon and energy from organic compounds (ex. glucose/cellular respiration)
a. Saprobes
b. Parasites

Other chemoheterotrophs/parasites

1. - Derive nutrients from the cells or tissues of a host
2. Also called (27) _pathogens__- because they cause damage to tissues or even death
3. Ectoparasites- live on the body
4. (28) _endoparasites__- live in organs and tissues
5. (29)_Intracellular__

Other chemoheterotrophs/saprobes (6)

1. - Free-living microorganisms
2. - Feed primarily on organic detritus from dead organisms
3. - Decomposers of plant litter, animal matter, and dead microbes
4. - Most have rigid cell wall, so they release (25)_enzymes/exoenzymes__ to the extracellular e

transport mechanisms for nutrient absorption

1. Cells must take nutrients in and transport waste out
2. Transport occurs across the cell membrane, even in organisms with cell walls
3. Properties of the membrane dictate which items pass through

The movement of water: Osmosis

1. Osmosis: (31) _diffusion__ of water through a selectively permeable membrane (has to have water in the sentence)
2. The membrane is selectively permeable (b/c hydrophilic & hydrophobic) - having passageways that allow free diffusion of water but can bl


is moving from high to low
diffusion of atoms or molecules

Osmotic relationships

The osmotic relationship between cells and their environment is determined by the relative concentrations of the solutions on either side of the cell membrane


1. (33) _Isotonic______: The environment is equal in solute concentration to the cell's internal environment
a. No net change in cell volume
b. Generally the most stable environment for cells


1. (34)_Hypotonic__: The solute concentration of the external environment is lower than that of the cell's internal environment
a. More water molecules outside of the cell
b. Net direction of osmosis is from the hypotonic solution into the cell
c. Cells w


1. (35)_Hypertonic___: The environment has a higher solute concentration than the cytoplasm
a. Will force water to diffuse out of a cell
b. Said to have high osmotic pressure
c. Method of food preservation

adaptations to Osmotic variations in the environment (2)

1. Example: fresh pond water- hypotonic conditions
a. Bacteria- cell wall protects them from bursting/creates turgor pressure.
b. Amoeba- a water (or contractile) vacuole that moves excess water out of the cell
2. Example: high-salt environment- hypertoni

The movement of molecules: diffusion & transport

1. Diffusion: When atoms or molecules move in a (36) _gradient___ from an area of higher density or concentration to an area of lower density or concentration
2. Largely determined by the concentration gradient and permeability of the substance
3. Random

Facilitated diffusion (5)

1. Utilizes a (40)__carrier protein__ that binds a specific substance, changes it's conformation, and the substance is moved across the membrane. has to be able to deal w/polar or nonpolar
2. Once the substance is transported, the carrier protein resumes

Active transport

1. Nutrients are transported **against the diffusion gradient or in the same direction as the natural gradient but at a rate faster than by diffusion alone
2. Requires the presence of specific membrane proteins (permeases and pumps)
3. Requires the expend

Endocytosis: Eating & drinking by cells

1. A form of active transport, uses energy unless passes thru freely.
2. Transporting large molecules, particles, lipids, or other cells (how immune system works)
3. Occurs in some eukaryotic cells (protists & mammals)
4. The cell encloses the substance i

Environmental factors that influence microbes

1. Temperature Adaptations
a. Microbial cells cannot control their temperature, so they assume the ambient temperature of their natural habitat
b. The range of temperatures for the growth of a given microbial species can be expressed as three cardinal tem

Psychrophile (3)

1. A microorganism that has an optimum temperature below 15�C and is capable of growth at 0�C. (water freezes so there must be adaptations. 70% made up of water)
2. True psychrophiles are (51)_obligate (biologically essential for survival)_ with respect t

Mesophile (4)

1. An organism that grows at intermediate temperatures
2. Optimum growth temperature of most: (53) 20C-40C (inside or outside the human body)
3. Temperate, subtropical, and tropical regions
4. Most (54) _human pathogens __ have optimal between 30�C and 40

Thermophile (4)

1. A microbe that grows optimally at temperatures greater than 45�C
2. Vary in heat requirements
3. General range of growth of 45�C to 80�C
4. (55) _Hyperthermophiles__: grow between 80�C and 120�C
*limited by enzymes and cell structures - naturally adapt

Gas requirements (3)

1. Atmospheric gases that most often influence microbial growth- O2 and CO2
2. Oxygen gas has the greatest impact on microbial growth
3. As oxygen enters into cellular reactions, it is transformed into several toxic products (Exa. [57])
H2O2, O2-, O OH-

O2 requirements: aerobe

can use gaseous oxygen in its metabolism and possesses the (59)_enzymes____(s) needed to process toxic oxygen products

O2 requirements: obligate aerobe

cannot grow without oxygen

O2 requirements:

(60)__facultative anaerobe__: an aerobe that does not require oxygen for its metabolism and is capable of growth in the absence of it

O2 requirements: microaerophile

does not grow at normal atmospheric concentrations of oxygen but REQUIRES a small amount of it in metabolism (but not amount in atmosphere)

O2 requirements: anaerobe

lacks the metabolic enzyme systems for using oxygen in (61)_respiration_______

O2 requirements: strict, or obligate, anaerobes

also lack the enzymes for processing toxic oxygen and cannot tolerate any free oxygen in the immediate environment and will die if exposed to it.

O2 requirements: aerotolerant anaerobes

Aerotolerant anaerobes do not utilize oxygen but can survive and grow to a limited extent in its presence

Fluid thioglycolate medium

(63)_Reducing____ media- absorbs oxygen or slows its penetration in the medium; used for growing anaerobes or for determining oxygen requirements

carbon dioxide

1. All microbes require some carbon dioxide in their metabolism
2. Capnophiles (64) : grow best at higher CO2 tension than in atmosphere

effects of pH

1. Majority of organisms live or grow in habitats between pH 6 and 8
2. Obligate (65) _acidophiles_(acid extremes)____
a. Euglena mutabilis- alga that grows between 0 and 1.0 pH
b. Thermoplasma- archae that lives in hot coal piles (sulfuric acid) at a pH

osmotic pressure (4)

1. Most microbes live either under hypotonic or isotonic conditions
2. Osmophiles- live in habitats with a high solute concentration
3. (66) _Halophiles___ prefer high concentrations of salt (grow on Mannitol salt)
4. Obligate halophiles- grow optimally i

Miscellaneous environmental factors

1. Nonphotosynthetic microbes tend to be damaged by the toxic oxygen products
a. Some produce yellow carotenoid pigments to protect against the damaging effects of light by absorbing and dismantling toxic oxygen
2. Other types of radiation that can damage

Ecological associations among microorganisms

1. Most microbes live in shared habitats (experience competition)
2. Interactions can have beneficial, harmful, or no particular effects on the organisms involved
3. They can be obligatory or nonobligatory to the members
4. They often involve nutritional


1. A general term used to denote a situation in which two organisms live together in a close partnership
a. Members are termed symbionts
b. Three main types of symbionts
i. (67)___Mutualism (+/+)_____: when organisms live in an obligatory but mutually ben

Nonsymbiotic relationship

1. Organisms are free-living and relationships are not required for survival
a. Synergism: (70) member cooperate & share nutrients. Interrelationship btw organisms, benefits but not necessary
b. Antagonism: an association between free-living species that

interrelationships btw microbes & humans (2)

1. Normal microbiotia: microbes that normally live on the skin, in the alimentary tract, and in other sites in humans
a. Examples (71) E. Coli, Lactobacillus (from yogurt), S. aureous, yeast/candida)
2. Can be commensal, parasitic, and synergistic relatio

The study of microbial growth (2)

1. Growth takes place on two levels
a. Cell synthesizes new cell components and increases in size & increase # of components w/in
b. The number of cells in the population increases
2. The Basis of Population Growth: (72) __Binary fission (every organism s

The rate of population growth (5)

1. Generation or (73) __doubling___ time: The time required for a complete fission cycle
2. Each new fission cycle or generation increases the population by a factor of 2
3. As long as the environment is favorable, the doubling effect continues at a const

The population growth curve (3)

1. A population of bacteria does not maintain its potential growth rate and double endlessly
2. A population displays a predictable pattern called a growth curve
3. The method to observe the population growth pattern:
a. Place a tiny number of cells in a

Stages in the normal growth curve (5)

1.Data from an entire growth period typically produce a curve with a series of phases
2. Lag Phase
3. Exponential Growth Phase
4. Stationary Growth Phase
5. Death Phase

Lag phase (6)

1. Relatively "flat" period
2. Newly inoculated cells require a period of adjustment, enlargement, and synthesis (getting acclimated to environ. not making bacteria but a lot of changes inside)
3. The cells are not yet multiplying at their maximum rate

exponential growth (Logarithmic or log) phase (3)

1. When the growth curve increases geometrically
2. Cells reach the maximum rate of cell division
3. Will continue as long as cells have adequate nutrients and the environment is favorable

stationary growth phase

1. The population enters a survival mode in which cells stop growing or grow slowly. plateau
a. The rate of cell inhibition or death balances out the rate of multiplication
b. Depleted nutrients and oxygen
c. Excretion of organic acids and other biochemic

death phase (2)

1. The curve dips downward
2. Cells begin to die at an exponential rate
3. more competition, less nutrients

other methods of analyzing population growth (2)

1.Turbidometry- a tube of clear nutrient solution becomes turbid as microbes grow in it
2. Define turbid (75) cloudy from growth of microbes

enumeration of bacteria

1. Direct or total cell count- counting the number of cells in a sample microscopically
a. Uses a special microscope slide called a (76)_cytometer___
b. Used to estimate the total number of cells cytometer in a larger sample
c. What is the problem with co

automated counting (3)

1. Coulter counter- electronically scans a culture as it passes through a tiny pipette
2. Flow cytometer also measures cell size and differentiates between live and dead cells
3. Real-time PCR [(78) polymerase chain reaction___] allows scientists to quant

taq polymerase (1/2) EXAM/QUIZ

enzyme that added can handle high temp.
have to have proteins that don't break apart/denature. can melt plasma membranes, so they have to have ways to stabilize.

taq polymerase (1/2) EXAM/QUIZ

PCR = polymerase chain reaction
1. xerox copy of dna. heat up increase 70C & bonds break. Taq polymerase can add in the matching strand of dna, then cools down & glues together.
2. Thermus aquaticus - yellowstone park, in hotspring. semi-conservative repl

inorganic nutrients

no carbon or hydrogen

organic nutrients

contain carbon & hydrogen

obligate saprobe

exist strictly on dead organic matter in soil & water

facultative parasite

when a saprobe infects a host, usually when the host is compromised (opportunisticf pathogen)

intracellular parasites
obligate parasites

ectoparasites - live on the body
endoparasites- live in organs & tissues
intracellular parasites - live within cells


Mutualism (+/+)_____: when organisms live in an obligatory but mutually beneficial relationship


ii. Commensalism: the member called the commensal receives benefits, while its coinhabitant is neither harmed nor benefited (+/o).


- Satellitism: (68) - one organism breaks down food source so another can use by-products


iii. (69) __Parasitism (+/-)__: a relationship in which the host organism provides the parasitic microbe with nutrients and a habitat


a. Synergism: (70) member cooperate & share nutrients. Interrelationship btw organisms, benefits but not necessary
Ex. intestines - release bacterocins for other microbes coming in. Bacterocins use to inhibit other microbes


1. Antagonism: an association between free-living species that arises when members of a community compete
a. One microbe secretes chemical substances into the surrounding environment that inhibit or destroy another microbe in the same habitat
ex. intestin


- live in habitats with a high solute concentration


prefer high concentrations of salt (grow on Mannitol salt)

Obligate halophiles

grow optimally in solutions of 25% NaCl but require at least 9% NaCl for growth

obligate parasites

-unable to grow outside of a living host