Micro Exam 2: Class Notes

macro

micro

• required in relatively large amounts
• N. CHOPS

required in trace amounts, often adequately supplied in water

Mn, Zn, Co, Mo, Ni, Cu

silicilic acid

components of CHO, lipids, proteins, nucleic acids

macronutrient necessary for enzyme activity

macronutrient/ heat resistance

cofactor for enzymes and complexes with ATP

cofactor for enzymes and electron-carrying proteins

• 1) autotrophs use CO₂ as sole C source
• 2) heterotrophs use preformed organic molecules as C source
• 3) microbial survival

light

from oxidation of organic or inorganic compounds

reduced inorganic compounds

reduced organic compounds

obtain energy from light and therefore use inorganic electron donors only to fuel biosynthetic reactions

• 1) use light energy and CO₂ as C source
• 2)Eucaryotic

• 1) purple and green bacteria
• 2) common inhabitants of polluted lakes and streams
• 3) use organic matter, electron donor, and C source

• 1) oxidizes reduced inorganic compounds
• ex) Fe, N, S molecules
• 2)chemical transformation of elements
• ex) NH₄⁺ to NO₃^- (N-cycle)

• O - 20%
• N - 78%

fix their own nitrogen

• 1) demonstrate great metabolic flexibility
• 2) Alter metabolic paths in response to environmental changes
• 3) nonsulfur bacteria

photoorganotrophic heterophytes under anaerobic conditions but oxidize organic molecules chemolithotrophically at normal O₂ levels

• 1) present in nucleic acids, phospholipids, nicleotides (ATP), and others
• 2) direct OP uptake by transport proteins
• 3) most use inorganic

• 1) needed in the synthesis of certain amino acids, eg; cystein and methionine
• 2) meets requirements by assimimlatory sulfate reduction

• 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)

• 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

• 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

• 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

use ATP to drive transport against a concentration gradient

• 1. symport
• 2. antiport

• 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

• 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

• 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

the breakdown of larger, more complex molecules into smaller, simpler ones during which energy is release, trapped, & made available for work

the synthesis of complex molecules from simpler ones during which energy is added as input

synthesis of complex molecules

nutrient uptake, waste elimination, ion balance

internal & external movement

• a. major source of biological energy
• b. photoautotrophs and chemolithoautotrophs trap energy and use some to produce organic molecules from CO₂

carbon

amount of heat energy needed to raise 1.0 gram of water from 14.5 to 15.5*C

energy can be neither created nor destroyed

physical & chemical processes proceed in such a manner that disorder of the universe increases to the max. possible

disorder

endergonic

positive stadard free energy

terminal P

strongly exergonic

negative standard free energy

high phosphate group

the high energy potential

ADP + P_i

protein catalysts with great specificity

increases the rate of a reaction without being personally altered

rate limiting enzymes

the end product inhibits the pacemaker enzyme that catalyzes the slowest (rate-limiting) reaction

fermentation, aerobic respiration, anaerobic respiration

organic energy souce oxidized & degraded without the use of an exogenous electron acceptor

• 1) glycolysis
• 2) pentose phosphate pathway
• 3) Entner-Duodoroff pathway

Embden-Meyerhof 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)

• 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-PO₄
• 3. Produces NADPH- source of electrons for biosynthesis
• 4. 4- & 5-C skeletons can be used for synthesis of macromolecules (amino-acids; nucleic acids)

• 1) most bacteria use the glycolytic and pentose pathways, but some substitute the E-D for glycolysis
• 2) produces ATP, NADPH, and NADH

• 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

ethanol & CO₂

Lactic acid (lactate)

homolactic fermentors

heterolactic fermentors

mixed acids or butane diol

• 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 CO₂
• 3. ATP is produced in substrate-level phosphorylation
• 4. 3 molecules NADH & 1 of FADH are produced

2 ATP's

(depending on precise nature of electron transport system) 2 to 38 ATP's

an increase in cellular constituents that may result in an increase in cell size, an increase in cell number, or both

total population numbers

• 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

• Biotic
• Abiotic

meaning of or related to life, are living factors. Plants, animals, fungi, protist and bacteria are all biotic or living 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.

the condition and nature of the microorganisms and the culture medium

• 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 Factor
• 6. Growth rate increase with increasing nutrient concentration to point of diminishing returns

• 1. period in which number of viable microorganisms remains constant because:
• a) metabolically active cells stopped reproducing
• b) reproductive rate = death rate

• a) nutrient limitation
• b) toxic waste accumulation (alcohol 13%)
• c) cell density (space)

the responses may include changes in morphology, gene expression & physiology

• 1. cells irreversible loss of ability to reproduce
• 2. period during which cells are dying at an exponential rate

time required to double population

• 1. ability to adapt to adverse conditions
• 2. prokaryotes grow in harsh environmental conditions that kills most other organisms

• temperature
• radiation
• o₂ levels
• pressure
• pH
• solutes and water activity

• 1. interaction with solutes (osmotic effect)
• 2. absorption to solids (matric effect)

the amount of water available to microorganisms

A_w=V_p(solution)/V_p of pure water

can grow in solutions of both high and low A_w

halophiles

pH=-log[H⁺]; log(1/[H⁺])

0-5.5

5.5-8.0

8.5 - 11.5

10 or higher