CHapter 6- Microbial Metabolism Flashcards
Microbial cells must always do 2 things
synthesize new parts (cell walls , ribosomes, nucleic acids) and harvest/convert energy to power reactions
sum total of all enzymatic chemical reactions in cell/ living organisms to maintain life
metabolism
Synthesizing new parts & harvesting energy to power reactions
metabolism, cells must do this
process that degrades compounds (glucose) to release energy; cell use the energy to synthesize ATP
Catabolism
harvest the energy released during the breakdown of compounds and use it to make ATP
Catabolism
What is produced from catabolic processes?
Precursor metabolites/ waste products (acids, carbon dioxide)
compounds produced during catabolism that can either be further degraded or used in anabolism to make subunits of macromolecules
precursor metabolites
chemical reactions that synthesize and assemble subunits of macromolecules, using ATP for energy
anabolism/biosynthesis
________ processes produce ATP , _______ use ATP
catabolic ; anabolic
capacity to do work;
energy
kinetic energy
moving energy; energy of motion
potential energy
stored energy
photosynthetic organisms harvest energy from?
sunlight
obtain energy from organic compounds
Chemoorganotrophs
energy available to do work; energy released when bond is broken
free energy
reaction that releases energy bc reactants have more free energy than products
exergonic reactions
reaction that requires energy bc products have more free energy than reactants
endergonic reactions
energy released from ______ reactions drives _________ reaction. energy released from ________ processes drives _________ processes.
exergonic/endergonic; catabolic/ anabolic
series of chemical reactions that converts starting compounds to end products
metabolic pathways (can be linear, branched,
why are enzymes important to metabolic pathways?
Without enzymes, energy yielding reactions would occur too slowly
Role of enzymes in reactions
enzymes speed up conversion of substrates into product by lowering activation energy
substance which enzymes acts/performs on to perform products
substrates
initial energy required to break chemical bond
activation energy
biological catalysts that increase rate of reaction by lowering activation energy
enzymes
enzyme characteristics
highly specific for substrates, cannot be changed by reactions and are reusable
site on enzyme where substrate binds by weak forces;
active site
binding of substrate to active site that causes slight change of enzyme shape so bonds get destabilized and new ones can form
enzyme substrate complex
assistance of an attached non protein component required by some enzymes
cofactor (Mg, Zi, Cu + trace elements)
assistance of a loosely bound non protein ORGANIC compound that help enzymes transfer molecules/electrons; derived from vitamins
coenzymes (FAD, NAD+, NADP+)
energy currency of cell
ATP
How do cells use energy to make ATP?
by adding and inorganic phosphate to ADP to yield ATP
How do cells release energy from ATP?
from removing inorganic phosphate from ATP to yield ADP
Processes chemoorganotrophs use to make ATP
substrate-level phosphorylation and oxidative phosphorylation
chemical addition of a phosphoryl group to an organic compound
phosphorylation
phosphorylation where energy generated in exergonic reactions
substrate level
phosphorylation where energy generated by proton level force
oxidative
substance that lose electrons is
oxidized
substances that gain electrons
reduced
electron equivalent to
hydrogen bc hydrogen has 1 electron
lost of a hydrogen (dehydrogenation)
oxidized
gain of a hydrogen (hydrogenation)
reduction
role of electron/hydrogen carriers
reduced form of these carriers represent reducing power that drives ATP synthesis
shuttles electrons: readily accept and donate electrons
electron carriers
Reduced electron carriers that represent reducing power (NADH, NADPH)
bc they can easily transfer electron to molecule with a higher affinity for electrons
Catabolism examples
Glycolysis, Pentose phosphate pathway, Tricarboxylic Acid Cycle “Krebs Cycle”
Splits glucsoe into 2 pyruvate molecules; produces moderate ATP, precursor metabolites, reducing power
Glycolysis
primarily produces precursor metabolite, NADPH
Pentose Phosphate
metabolic intermediates (from catabolic processes) that can be either used (in anabolic pathways) to make the subunits of macromolecules or oxidized to generate ATP.
precursor metabolites (carbon skeletons)
transfers electrons from glucose to electron transport chain
Respiration
this generates proton motive force
electron transport chain
uses Electron Transport Chain & oxygen as terminal electron acceptor; produces most ATP
aerobic respiration
uses ETC, uses molecule other than oxygen as electron acceptor, amount of ATP produced varies
Anaerobic respiration
If cells cannot respire, glycolysis
will stop
does not use ETC or Krebs Cycle, uses pyruvate or another derivatives as electron acceptor, produces just 2 ATP (small amounts)
fermentation
Fermentation and respiration both begin with this same step
Glycolysis
two stages of glycolysis
prep stage (energizes glucose) and pay off stage (uses glucose to make ATP)
has specific nutritional requirements to grow; requires things other than glucose to grow; may require precursor metabolites
fastidious organism
only requires glucose for growth
non fastidious organism (ex: E. coli)
______ produces more ATP than _____
respiration; fermentation
Prep Stage of glycolysis
Glucose is energized, then split into 2 G3Ps (both phosphorylated). This stage results in the making of 2 G3Ps by using 2 ATPs
In prep stage, you have to ________________ so you get back nothing
spend money, to make money
How does cell make energy from glycolysis?
recycles ATP
When ATP is used by the cell to do work, the result is
ADP and an inorganic phosphate
What does cell do with harvested inorganic phosphate?
It is added to the two G3Ps
How is inorganic phosphate added to the G3P molecules?
An enzyme will remove a hydrogen (H+) atom from G3P to clear a spot for inorganic phosphate to be added (enzyme oxidizes G3P) …. H atom is added to NAD+ ——> forming NADH (reduced)
What must be in constant supply for glycolysis to continue?
NAD+
The same enzyme that oxidizes G3P for a spot for inorganic phosphate to be added is
the same enzyme that reduced NAD+ to form NADH so the phosphate can be added to the G3P; Both G3Ps end up with 2 phosphates each and cell can harvest 4 ATPS
Pay Off Stage
EACH G3Ps oxidized by NAD+ and inorganic phosphates added each making 1/3 bisphos, each have 2 phosphates transferred to 2ADP making 2ATPs, what remains after each 2 ATPs created is waste product (pyruvate acid)
Glycolysis results - USED
1 glucose, 2 ATP, 2 inorganic Phosphates, 2 NAD+
Glycolysis results- Products
4 ATP, 2 Pyruvate, 2 NADH (Net is 2 ATP bc 2ATP were used to make 4 ATP)
Cells reduced NADH back to NAD+ by (because NAD+ needs to be recycled as it is needed for glycolysis to keep going)
cellular respiration and fermentation
Produces large amount of ATP via Electron Transfer Chain
Cellular Respiration
membrane embedded electron carriers that pass electrons back and forth creating proton motive force
electron transport chain
ETC causes
gradient of H atoms where H concentration is higher outside of membrane than inside
Gradient of H+ atoms will want to flow back, but cannot bc it is being blocked by
a SEMI permeable MEMBRANE
What keeps gradient stable with High conc of H outside membrane and low H conc inside?
The Hydrogen pumped into membrane combine w oxygen and created water so it does not participate with the pumping
This enzyme uses energy of proton motive force to synthesize ATP
ATP Synthase
Electron Transport Chain (Oxidative Phosphorylation) produces
36 ATPs per glucose molecule
NADH adds H to Pyruvic Acid directly resulting in pyruvic acid turning into
Lactic Acid Fermentation
Pyruvate Acid loses CO2, then NADH adds H to CHO resulting in
alcohol fermentation
ETC found in ______ in prokaryotes and _______ eukaryotes
plasma membrane; mitochondrial inner membrane
Can glycolysis be ran by things other than glucose?
Yes
Energy being made from flow of hydrogen
in ETC
lessens the amount of energy needed for a reaction to occur (lowers activation energy)
enzyme
many cell reactions are _______ and need enzymes
endergonic
