Microbial Metabolism (Energetic and Redox #2) Flashcards
1) source of energy
2) source of electrons
3) water
4) nutrients
requirements for microbial survival and growth (4):
source of energy
requirement for microbial survival/growth: used for cellular WORK; all cells have to do this
source of electrons
requirement for microbial survival/growth: play a role in energy production; reduce CO2 to form organic molecules; help make macromolecules
nutrients
requirement for microbial survival/growth: to synthesize organic building blocks needed for cell maintenance and growth
- carbon (C)
- hydrogen (H)
- oxygen (O2)
which nutrients are required for microbial survival and growth?
- organic or inorganic chemical compounds
- sunlight (ENERGY only)
sources of energy + electrons (2):
oxidizing (removing electrons) from a compound
how is energy obtained through organic or inorganic chemical compounds?
no (just energy here)
can you obtain electrons from sunlight?
ATP (adenosine triphosphate)
energy (Proton Motive Force) is usually conserved in cells as ______
- chemicals
- light
energy sources (2):
chemotrophy
cells gain energy from chemicals through ________: EATING chemicals
phototrophy
cells gain energy from light through ________: getting Energy from the Sun
organic or inorganic
cells can either eat ______ chemicals or ______ chemicals
chemoorganotrophs
cells that eat organic chemicals
chemolithotrophs
“rock eaters;” cells that eat inorganic chemicals for energy
E. coli
example of chemoorganotrophs =
Thiobacillus thiooxidans
example of chemolithotrophs
phototrophs
cell that gain energy through the sun/light
R. capsulatus
example of phototroph =
carbon AND hydrogen
organic elements (2):
carbon
inorganic substances = NO ________
no because there is no hydrogen
is CO2 organic?
energy source or electron source OR carbon source
nutritional types of organisms can be based on _____ sources or ______ sources OR ______ source
-phototrophs
- chemotrophs
Nutritional Types of Organism based on ENERGY source (2):
phototroph
Nutritional Type of Organism based on E source: use light
chemotroph
Nutritional Type of Organism based on E source: obtain energy from OXIDATION of chemical compounds
- lithotrophs
- organotrophs
Nutritional Types of Organisms based on ELECTRON source (2):
lithotrophs
Nutritional Type of Organisms based on ELECTRON source: use REDUCED inorganic substances
organotrophs
Nutritional Type of Organisms based on ELECTRON source: obtain electrons from organic compounds
- heterotrophs
- autotrophs
Nutritional Types of Organisms based on CARBON source (2):
heterotrophs
Nutritional Type of Organisms based on CARBON source: use organic molecules as carbon sources (which often serve as energy and electron source as well**)
autotrophs
Nutritional Types of Organisms based on CARBON source: use CO2 as their sole or principle carbon source; must obtain energy and electrons from other sources; “primary producers”
chemoorganoheterotroph
1 most common nutritional type of microorganism
organic sources
where do chemoorganoheterotroph get their carbon source, energy source, AND electron source from?
photolithoautotroph
2 most common nutritional type of microorganism
CO2
where do photolithoautotrophs get their carbon source from?
light
where do photolithoautotrophs get their energy source from?
inorganic e- donor / source
where do photolithoautotrophs get their electron source from?
chemoorganoheterotrophs
what nutritional type are humans?
metabolism
total of all chemical reactions occurring in the cell
- catabolism
- anabolism
2 parts of metabolism:
catabolism
type of metabolism: fueling reactions; energy-conserving reactions; provide REDUCING power (aka electrons); generate precursors for biosynthesis – breaking things DOWN
anabolism
type of metabolism: the synthesis of complex organic molecules from simpler ones; requires energy, electrons, and building blocks from fueling reactions – building things UP
- chemical
- transport
- mechanical
types of work carried out by microorganisms (BIOENERGETICS - 3):
chemical
type of work: synthesis of new cellular material
transport
type of work: take up nutrients, repair and replace, elimination of wastes, and maintenance of ion balances
mechanical
type of work: motility of cells; chemotaxis
energy
capacity to do work or cause particular changes
G (free energy)
the amount of energy that is available to do useful work
∆G°’
the change in free energy during a chemical reaction for standard conditions (pH 7, temp. of 25°C, 1 atm, reactants and products at 1 M concentration)
- exergonic reactions
- endergonic reactions
types of Free Energy Change reactions (2):
exergonic
type of Free Energy Change reaction: release energy
endergonic
type of Free Energy Change reaction: require energy
products
in exergonic reactions, energy is in the ________ of the reaction
reactants
in endergonic reactions, energy is in the ______ of the rxn
NEGATIVE
in EXERGONIC reactions, ∆G°’ is _______
POSITIVE
in ENDERGONIC reactions, ∆G°’ is _______
exergonic (since ∆G°’ is negative)
free energy change reaction: proceeds spontaneously
endergonic (since ∆G°’ is positive)
free energy change reaction: will NOT proceed spontaneously
catabolism
exergonic reactions are what type of metabolism?
anabolism
endergonic reactions are what type of metabolism?
electron
many metabolic processes involve redox reactions, which are ______ transfers
donor to acceptor
electron carriers are often used to transfer electrons from an electron _______ to an eletron _____
energy
redox reactions can result in ______ release, which can be conserved as ATP or another energy-rich compound
molecule
electrons CANNOT exist alone, they must be a part of a _______
oxidation
REMOVAL of an electron (or electrons) from a substance
reduction
ADDITION of an electron (or electrons) to a substance
reduced
more hydrogens = ______ form
Oxidation is LOSS
Reduction is GAIN
what does OIL RIG stand for?
proton (H+)
oxidation and reductions frequently invovle the transfer of not just electrons, but both an electron (e-) PLUS a _______
oxidized
NAD+ = _____ form
reduced
NADH + H+ = ______ form
glucose + 6oxygen <——> 6 CO2 + 6 water
respiration formula:
CO2
in respiration, glucose is the reduced form of _____
oxygen
in respiration, water is the reduced form of _______
donor
in respiration, glucose is an electron ______
“nanny”
NAD is termed the _______
reduced
oxidized
in respiration, oxygen is ______ to water and glucose is _______ to CO2
oxidation
electrons released during the _______ of chemical energy sources must be accepted by an electron acceptor
electron transport; PMF
In chemotrophs, organic electron DONORS must go through _______ _____/generation of _____ to give electrons to to electron ACCEPTORS in aerobic + anaerobic respiration
fermentation (endergonic)
if chemotrophs don’t go through respiration, they can go through __________
T/F: fermentation is a type of anaerobic repsiration
false (its its OWN things)
equilibrium constant for oxidation-reduction reaction; a measure of the tendency of the reducing agent to LOSE electrons; “How many e- are they capable of giving??”
Standard Reduction Potential (E’0)
more negative E’0, the better electron ______
DONOR
more positive E’0, the better electron ______
ACCEPTOR
on the Redox Tower, more _______ E’0 substances are on the top and more _______ E’0 substances are on the bottom
negative = TOP
positive = BOTTOM
on the Redox Tower, electrons go down or up the tower?
down!
the greater the difference between the E’0 of the donor and the E’0 of the acceptor, the more _______ the ΔG°’
negative
the redox tower goes from _____ donors to ______ acceptors
reduced donors; oxidized acceptors
the further the e- travels down the tower, the ______ energy is released
more
Redox Tower: the more e-, the more likely they are to ______
donate (aka more neg. - top of tower)
oxidized form = electron ______
acceptor
reduced form = electron ______
donor
you can tell which is the reduced form by looking at what?
more one with more e- (or Hs)
oxidized/reduced forms are also called ________
agents
_____ forms are WITHOUT e-
oxidized
_____ forms are WITH e- (lots of H’s)
reduced
when writing oxid./reduc/ forms, what is the order?
oxidized form / reduced form
flow of electrons down the tower _____ energy
releases
light energy is used to drive electrons ______ the tower during photosynthesis
up
2 classes of electron carriers:
1) coenzymes
2) prothetic groups
class of e- carriers: freely diffusible (around the cell); can transfer electrons from one place to another in the cell (“nannies picking up the babies in their mini van”)
coenzymes
example of coenzyme =
NAD+
class of e- carriers: firmly attached (fixed) to enzymes in the plasma membrane; function in membrane-associated electron transport reactions (“home nannies”)
prothetic groups
class of e- carriers: firmly attached (fixed) to enzymes in the plasma membrane; function in membrane-associated electron transport reactions
prosthetic groups
example of prosthetic group =
cytochromes
NAD+ (or NADP+) stands for:
nicotinamide adenine dinucleotide (phosphate)
NAD+ (or NADP+) is a _______
coenzyme (“nanny that can drive”)
NAD+ can carry ______ electrons + ____ H+
2 e- and 1 H+
NAD+ is involved in which type of metabolism?
catabolism (break down)
NADP+ is involved in which type of metabolism?
anabolism (build up)
NADH and NADPH are good electron ________
donors
recution potential of redox couple of NADH and NADPH is ______ V
-0.32 V
NADH and NADPH only accept electrons from things ______ them for CATABOLISM and can only give electrons to things ______ them for ANABOLISM
above; below
NADH is the ______ form of NAD+
reduced
what is the only way to go UP the tower?
photosynthesis
T/F: important e- carriers (NAD+) can be re-used bc cells do not have that many – if they run out they die
True
steps of NAD+/NADH cycling (
NAD+ reduction steps:
1) enzyme I reacts with e- donor and oxidized form of coenzyme, NAD+
2) NADH and reaction product are formed
NADH oxidation steps:
3) enzyme II reacts with electron acceptor and reduced form of coenzyme, NADH
Catabolism turns ________ to ________ when transforming reactants to products
ADP + Pi into ATP
Anabolism turns _____ to ________ when transforming Precursors into Cellular Materials
ATP into ADP + Pi
________ produces ATP and _________ uses ATP
catabolism prod.
anabolism uses
energy currency of the cell =
ATP
about ATP is ______ kJ/mol of energy is released when ATP is hydrolyzed to ADP + Pi (first bond of P is broken)
- 32 kJ/mol
roughly _______ kcal/mol of energy is released when ATP is hydrolyzed
7/6 kcal/mol
ATP has a _____ phosphate transfer potential
high
second bond of phosphate in ATP can be broken but gives less energy — close enough to call it another _____ kJ/mol
-32 kJ/mol
can the third P bond in ATP be broken?
no, its too stable and would give barely any energy
is the energy from ATP negative or positive?
negative bc energy is RELEASED
what do squiggly bond lines mean (like in ATP)?
they release more energy when broken
cells typically only break bonds that give them/release more than ____ kJ/mol of energy
30 kJ/mol
what other compounds do cells use for energy (4):
- phosphoenolpyruvate (-61.9 kJ/mol)
- acetyl-CoA (-35.7 kJ/mol)
- acetyl-phosphate (-44.8 kJ/mol)
- ADP
do cells typically use glucose-6-phosphate for energy?
no (only gives -13.8 kJ/mol)
mechanisms of ATP synthesis (3):
- substrate-level phosphorylation
- oxidative phosphorylation
- PHOTOphosphorylation
ATP synthesis mechanism: used in fermentation AND respiration (aerobic + anaerobic) and other pathways; ATP is synthesized during steps in the catabolism of an organic compound; in a pathway, you’ll see ATP coming off
substrate-level phosphorylation (SLP)
ATP synthesis mechanism: used in respiration; a lot more direct way to make ATP but more complex; ATP is produced by Proton Motive Force (PMF)
oxidative phosphorylation
ATP synthesis mechanism: used by phototrophic organisms; light drives the redox reactions that generate proton motive force
PHOTOphosphorylation
only ATP synthesis mechanism used for organisms that only perform fermentation to get energy
SLP (substrate-level phosphorylation)
in oxidative phosphorylation (and photophosphorylation, ATP is produced by _________
PMF (proton motive force)
substrate-level phosphorylation (SLP) used energy rich ________ to transform ADP to ATP
intermediates
oxidative phosphorylation uses the dissipation of ________ to make ATP
PMF
in the process of oxid. phosphorylation, the PMF is formed by converting an _______ membrane into a _____ ______ membrane
energized
less energized
an energized membrane has more _______ charges on the OUTSIDE and more ______ charges on the INSIDE
positive (outside)
negative (inside)
a less energized membrane has the same charge pattern (+ outside, - inside) but just less _____
charges
what does aerobic + anaerobic respiration and fermenation form ATP for (3)?
chemical, transport, and mechanical WORK
Chemoorganotrophic Fueling Processes (2):
- respiration
- fermentation
in respiration (for chemoorganotrophs), electrons go through the _______ to form the ______, which is used for ________ _____ to produce ATP
ETC
PMF
oxidative phosphorylation
final e- acceptor in AEROBIC respiration =
oxygen
final e- acceptor in ANAEROBIC respiration =
something other than oxygen
in respiration (for chemoorganotrophs), CARBON atoms can go through _______ to form ATP (and by-products of CO2 + biosynthesis); easy and fast
SLP
in fermentation (for chemoorganotrophs), CARBON atoms go through _____ to get ATP
SLP
in fermentation (for chemoorganotrophs), electrons go to _________ electron acceptors
ENDOGENOUS e- acceptors
what does endogenous e- acceptor mean?
e- acceptor is already made within the cell
example of endogenous e- acceptor =
pyruvate
