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large nutrient molecule
macro
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small nutrient molecule
micro
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macroelements/macronutrients
- required in relatively large amounts
- N. CHOPS
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trace elements/micronutrients
required in trace amounts, often adequately supplied in water
Mn, Zn, Co, Mo, Ni, Cu
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diatoms need __________ for cell wall
silicilic acid
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N CHOPS
components of CHO, lipids, proteins, nucleic acids
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K+
macronutrient necessary for enzyme activity
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Ca+2
macronutrient/ heat resistance
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Mg+2
cofactor for enzymes and complexes with ATP
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Iron
cofactor for enzymes and electron-carrying proteins
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requirement for C,H,O
- 1) autotrophs use CO2 as sole C source
- 2) heterotrophs use preformed organic molecules as C source
- 3) microbial survival
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energy source for phototrophs:
light
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energy source for chemotrophs:
from oxidation of organic or inorganic compounds
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electron source of lithotrophs:
reduced inorganic compounds
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electron source of organotrophs:
reduced organic compounds
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photolithotrophs
obtain energy from light and therefore use inorganic electron donors only to fuel biosynthetic reactions
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photolithotrophic autotrophs
- 1) use light energy and CO2 as C source
- 2)Eucaryotic
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photoorganotrophic heterotrophs
- 1) purple and green bacteria
- 2) common inhabitants of polluted lakes and streams
- 3) use organic matter, electron donor, and C source
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chemolithotrophic autotrophs
- 1) oxidizes reduced inorganic compounds
- ex) Fe, N, S molecules
- 2)chemical transformation of elements
- ex) NH4+ to NO3- (N-cycle)
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legume
fix their own nitrogen
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mixotrophics
- 1) demonstrate great metabolic flexibility
- 2) Alter metabolic paths in response to environmental changes
- 3) nonsulfur bacteria
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nonsulfur bacteria
photoorganotrophic heterophytes under anaerobic conditions but oxidize organic molecules chemolithotrophically at normal O2 levels
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Requirements for Phosphorus:
- 1) present in nucleic acids, phospholipids, nicleotides (ATP), and others
- 2) direct OP uptake by transport proteins
- 3) most use inorganic
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Requirements for Sulfur:
- 1) needed in the synthesis of certain amino acids, eg; cystein and methionine
- 2) meets requirements by assimimlatory sulfate reduction
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Passive Diffusion
- 1) a phenomenon in which molecules move from an area of high concentration to an area of low concentration because of random thermal agitation
- 2) requires a large concentration gradient for significant levels of uptake
- 3) limited only to a few small molecules (eg. O2, H2O, CO2, glycerol)
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Facilitated Diffusion
- 1) a process that involves a carrier molecule (permease) to increase the rate of diffusion
- 2) net effect is limited to movement from an area of higher concentration to an area of lower concentration
- a. requires smaller concentration gradient than passive diffusion
- b. generally more important in eukaryotes
- c. rate plateus when carrier becomes saturated
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Active Transport
- 1) process in which metabolic energy is used to move molecules to the cell's interior where solute concentration is already higher (against concentration gradient)
- 2) involves carrier proteins (permeases) with specificity for binding solutes transported
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Characteristics of active transport
- a. saturable uptake rate (similar to facilitated diffusion)
- b. requires expenditure of metabolic energy
- c. concentrates molecules inside the cell even when the concentration inside is already higher
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ATP- binding cassette transport (ABC transporters)
use ATP to drive transport against a concentration gradient
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Types of Active transport
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symport
- type of active transport: linked transport of 2 substances in the same direction (inward or outward)
- e.g. E. Coli permease- transports lactose & proton inward
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antiport
- type of active transport: linked transport of 3 substances in opposite directions
- e.g.: E. Coli Na+ transport system pumps Na+ outwards in response to inward movement of protons
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Iron uptake:
- a. Fe3+ and it's derivatives are extremely insoluable, little free iron available
- b. sidererophores (low MW) complex with very insoluble ferric ion, which is the transported into the cell
- c. secreted when little iron is available in medium
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catabolism
the breakdown of larger, more complex molecules into smaller, simpler ones during which energy is release, trapped, & made available for work
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anabolism
the synthesis of complex molecules from simpler ones during which energy is added as input
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chemical work
synthesis of complex molecules
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transport work
nutrient uptake, waste elimination, ion balance
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mechanical work
internal & external movement
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photosynthesis
- a. major source of biological energy
- b. photoautotrophs and chemolithoautotrophs trap energy and use some to produce organic molecules from CO2
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orgnaic molecules serve as source of ___________.
carbon
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calorie
amount of heat energy needed to raise 1.0 gram of water from 14.5 to 15.5*C
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First Law of Thermodynamics
energy can be neither created nor destroyed
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Second Law of Thermodynamics
physical & chemical processes proceed in such a manner that disorder of the universe increases to the max. possible
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cell reactions are mostly ___________.
endergonic
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endergonic
positive stadard free energy
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removal of __________ by hydrolysis goes almost to completion - ___________
terminal P
strongly exergonic
-
exergonic
negative standard free energy
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ATP has high ________________ transfer potential.
high phosphate group
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_______________ makes ATP well suited for it's tole in energy currency
the high energy potential
-
ATP is formed from _______________ by trapping processes.
ADP + Pi
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enzymes
protein catalysts with great specificity
increases the rate of a reaction without being personally altered
-
for any reaction to proceed to completion, it depends on ______________.
rate limiting enzymes
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feedback inhibition
the end product inhibits the pacemaker enzyme that catalyzes the slowest (rate-limiting) reaction
-
The 3 Main Sources of Energy for M.O.'s
fermentation, aerobic respiration, anaerobic respiration
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fermentation
organic energy souce oxidized & degraded without the use of an exogenous electron acceptor
-
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Three major routes of breakdown of glucose to pyruvate:
- 1) glycolysis
- 2) pentose phosphate pathway
- 3) Entner-Duodoroff pathway
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other name for glycolysis pathway
Embden-Meyerhof pathway
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Glycolytic pathway
- a) 6-Carbon sugar: glucose is phosphorylated twice --> fructose 1,6 bi-phosphate, using 2 ATPs
- b) 3-Carbon sugar: fructose 1,6 biphosphate cleaves into two 3-C molecules, each processed to pyruvate
- EACH 3-C YIELDS:
- -2 ATPs (total of 4 ATPs; not gain of 2 ATPs per glucose)
- - 1 NADH (2 NADHs per glucose)
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Pentose Phosphate Pathway
- 1. produces a variety of 3-, 4-, 5-, 6-,& 7-C sugar PO4's
- 2. converts 3 G-6-PO4 to 2 fructose-6-PO4 & a glyceraldehyde-3-PO43. Produces NADPH- source of electrons for biosynthesis
- 4. 4- & 5-C skeletons can be used for synthesis of macromolecules (amino-acids; nucleic acids)
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Entner-Duordoff (E-D) pathway
- 1) most bacteria use the glycolytic and pentose pathways, but some substitute the E-D for glycolysis
- 2) produces ATP, NADPH, and NADH
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fermentation
- 1. an energy-yielding process in which an energy substrate is oxidized without an exogenous electron acceptor
- 2. regeneration of NAD+ used during oxidation of glyceraldehyde-3-PO4 to 1,3-biphosphoglycerate
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alcoholic fermentation produce ___________.
ethanol & CO2
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Lactic acid fermentation produces ___________.
Lactic acid (lactate)
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________________ reduce pyruvate to lactate.
homolactic fermentors
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_____________ for substatial smounts of products other than lactate.
heterolactic fermentors
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Formic acid fermentation produces either ___________ or ____________.
mixed acids or butane diol
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Tri-carboxylic (TCA) Acid cycle
- 1. pyruvate can be degraded to CO2 by the TCA cycle after first being converted to acetyl-CoA
- 2. The reaction is accomplished by loss of one carbon atom as CO23. ATP is produced in substrate-level phosphorylation
- 4. 3 molecules NADH & 1 of FADH are produced
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yield of ATP by glycolysis during fermentation
2 ATP's
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aerobic respiration (# ATP's)
(depending on precise nature of electron transport system) 2 to 38 ATP's
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microbial growth
an increase in cellular constituents that may result in an increase in cell size, an increase in cell number, or both
-
microbiologists follow changes in _____________.
total population numbers
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LAG phase
- 1. period of apparent inactivity during which the cells are adapting to a new environment and preparing for reproductive growth
- 2. cell may be synthesizing new cell components
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Two factors how mucrobes function:
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Biotic factors
meaning of or related to life, are living factors. Plants, animals, fungi, protist and bacteria are all biotic or living factors
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Abiotic factors
meaning not alive, are nonliving factors that affect living organisms. Environmental factors such habitat (pond, lake, ocean, desert, mountain) or weather such as temperature, cloud cover, rain, snow, hurricanes, etc. are abiotic factors.
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phase varies in length depending on ____________________.
the condition and nature of the microorganisms and the culture medium
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LOG phase
- 1. period during which the microorganisms are growing @ maximal rate possible given their genetic potential, nature of medium & conditions
- 2. population is most uniform in terms of chemical & physical properties at this stage
- 3. balanced growth
- 4. microbe growth limited by low concentration of required nutrient
- 5. Increase in yield results when the limiting nutrient is supplied- Law of Limiting Factor6. Growth rate increase with increasing nutrient concentration to point of diminishing returns
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stationary phase
- 1. period in which number of viable microorganisms remains constant because:
- a) metabolically active cells stopped reproducing
- b) reproductive rate = death rate
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reasons for microbes to enter stationary phase:
- a) nutrient limitation
- b) toxic waste accumulation (alcohol 13%)
- c) cell density (space)
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responses to starvation/low nutrient concentration have practical medical and industrial applications
the responses may include changes in morphology, gene expression & physiology
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death phase
- 1. cells irreversible loss of ability to reproduce
- 2. period during which cells are dying at an exponential rate
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generation time
time required to double population
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Influence of encironmental factors on growth
- 1. ability to adapt to adverse conditions
- 2. prokaryotes grow in harsh environmental conditions that kills most other organisms
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Major environmental factors:
- temperature
- radiation
- o2 levels
- pressure
- pH
- solutes and water activity
-
Available H2O can be reduced by:
- 1. interaction with solutes (osmotic effect)
- 2. absorption to solids (matric effect)
-
Aw
the amount of water available to microorganisms
Aw=Vp(solution)/Vp of pure water
-
osmotolerant organisms
can grow in solutions of both high and low Aw
-
______________ require environment of low Aw (high osmotic pressure due to salt concentration) to grow
halophiles
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pH=
pH=-log[H+]; log(1/[H+])
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-
-
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extreme alkalophiles
10 or higher
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