Looks like no one added any tags here yet for you.
Metabolism
all of the chemical reactions inside a cell
unifying characteristics of all cellular organisms
Catabolism
carbohydrates, lipids, and proteins are chemically broken down
energy is released and transferred to ATP
smaller biomolecules (amino acids, fatty acids, and simple sugars) are produced
Anabolism
uses energy to synthesize macromolecules that make up the cell
Oxidation Reactions
removes electrons from donor molecules leaving them oxidized
loses electrons
electron donor is substance oxidized
Reduction Reactions
add electrons to acceptor molecules leaving them reduced
gaining electrons
electron acceptor is substance reduced
Reduction Potentials and Redox Couples
substances differ in their tendency to donate or accept electrons
expressed as E0 (V)
oxygen is the bottom of the redox tower, the strongest electron acceptor of significance in nature
Common Energy Carriers
originate from B vitamin group and are derivatives of nucleotides
nicotinamide adenine dinucleotide, nicotine adenine dinucleotide, and flavin adenine dinucleotide
Why are Energy Carriers so Important?
provide energy and can be coenzymes
Coenzymes
organic helper molecules required for enzyme action
ex: NADH and ATP: provide high energy electrons or phosphate group and bind to enzymes activating them
Catalysts
speed up a chemical reaction without being permanently altered themselves
lowers the activation energy of a chemical reaction
influenced by local environmental conditions like pH, substrate concentration and temp
Glycolysis
energy investment phase
splits glucose into pyruvate
uses energy from ATP molecules, two phosphorylated 3 carbon molecules (G3P)
energy payoff is gained by oxidizing G3P to pyruvate
net gain from glucose molecule breakdown:
two ATP molecules
two NAHD molecules
two pyruvate molecules
Krebs Cycle/ Tricarboxylic Acid Cycle (TCA)
occurs in cytoplasm of prokaryotes
takes place in mitochondrial matrix of eukaryotes
oxidation of pyruvate to release CO2
many organisms use intermediates from krebs cycle like amino acids, fatty acids, and nucleotides as building blocks for biosynthesis
per turn of cycle:
two CO2
three NADH
one FADH2
one ATP or GTP
Cellular Respiration
overall process of catabolism from substrate breakdown to reduction of terminal electron acceptor such as O2
uses glucose to produce ATP
completes catabolism by donating electrons from NADH to ETS in a process that stores energy by pumping proteins (H+) across the membrane to generate a gradient with hydrogen ions
Oxidative Phosphorylation
hydrogen ions return to the cell via ATP synthase, driving the formation of ATP
Electron Transport System (ETS)
series of chemical reactions where electrons from NADH and FADH2 are passed rapidly from one ETS carrier to the next
in aerobic respiration: final electron acceptor is an oxygen molecule (O2) that becomes reduced to water (H2O)
in anaerobic respiration: final electron acceptor is an inorganic molecule other than oxygen, aerobically respiring bacteria switch to nitrate as the final electron acceptor and produce nitrite when oxygen levels are low
Respiration of Glucose with Oxygen
C6H12O6 + 6 H2O → 12 H2O + 6 CO2
can generate a relatively large number of ATP molecules per molecule of glucose, more than fermentation
actual number produced varies on the amount of carbon and oxygen available
Lithotrophs
an alternative route to get electrons for ETS and PMF generation
inorganic, reduced, molecules serve as electron donors instead of organic compounds
ex: ferrous iron (Fe2+), ammonium ion (NH4+), hydrogen gas (H2)
oxygen or alternative gas serves as final electron acceptor for ETS
unique energy pathway used only by some types of bacteria
Fermentation
if respiration doesn’t occur NADH must be re-oxidized to NAD+ for reuse as electron carrier for glycolysis
does not involve the ETS bc it doesn’t directly produce any additional ATP beyond that produced during glycolysis by substrate level phosphorylation
Essential Nutrients
compounds a microbe cannot make itself but must gather from its immediate environment if the cell is to grow and divide
ex: carbon, nitrogen, phosphorous, hydrogen, oxygen, sulfur, magnesium, iron, potassium, and trace elements like cobalt, copper, and zinc
Growth Factors
required by some compounds, must be added to their culture before they grow
Autotrophs
make their own carbon compounds starting with CO2
Heterotrophs
obtain carbon compounds from other organisms
Requirements for Growth
physical: ph, temperature, moisture, hydrostatic pressure, osmotic pressure, and radiation
chemical: availability of carbon, nitrogen, sulfur, phosphorous, trace elements, organic compounds, and oxygen
Psychophiles
cold loving microbes
Mesophiles
moderate temperature loving microbes
Thermophiles
heat loving microbes