Ch.5: Microbial Metabolism Flashcards
Metabolism
The sum of all chemical reactions in a cell
Catabolism
- the breakdown of complex organic compounds into simpler ones
- are called catabolic or degradative reactions
- Break bonds and release energy
Anabolism
- the building of complex organic molecules from simpler ones
- called anabolic or biosynthetic reaction
- Making bonds, energy is used/absorbed
Diversity in prokaryotes are in their _______.
Chemistry (metabolism)
Possible carbon sources for prokaryotes
- Organic Carbon (hetero)
- Inorganic Carbon (auto) in the form of CO2
Possible energy sources for prokaryotes
- Sunlight (photo)
- Chemical compounds (chemo)
- organic compounds (organo)
- sugars, amino acids, etc.
- inorganic chemical (litho)
- H2, NH3, NO2-, Fe2+, H2S
- organic compounds (organo)
Photoautotroph
- Energy: Sunlight (photo)
- Carbon Source: Carbon Dioxide (auto)
Photoheterotroph
- Energy: Sunlight (photo)
- Carbon Source: Organics (hetero)
Chemolithoautotroph
- Energy: Inorganic Chemicals (litho)
- Carbon Source: Carbon Dioxide (auto)
Chemoorganoheterotroph
- Energy: Organic compounds (organo)
- Carbon Source: Organics (hetero)
ATP
- Energy currency of the cell
-
Adenine triphosphate
- 3 phosphate groups
- Ribose sugar
- Adenine nitrogenous base
ATP Hydrolysis
- Leads to ADP - Adenine diphosphate
- Ribose
- Adenine nitrogenous base
- 2 phosphate groups
Most enzymes are large _____ molecules
Protein
Location where the substrate binds to the enzyme
ACTIVE SITE
When a molecule loses an electron, it is ________
Oxidized
-
L.E.O
- Lose
- Electron
- Oxidized
When a molecule gains an electron, it is _______
Reduced
-
G.E.R
- Gain
- Electron
- Reduced
NAD+/FAD (vitamins)
-
Nicotinamide Adenine Dinucleotide & Flavin adenine dinucleotide
- Oxidized forms
- Electron Acceptors
NADH/FADH2
- Reduced forms
- Electron donor
Aerobic Cellular Respiration
C6H12O6 + O2 ——> CO2 + H20 + ATP
- Terminal electron acceptor is O2
- the product is water
- Generates roughly 38 ATP (34 from ETC, 2 from glycolysis, 2 from Krebs Cycle)
Steps to Aerobic Cellular Respiration
- Glycolysis
- Pyruvate Oxidation
- Kreb’s Cycle/Citric Acid Cycle/ TCA Cycle
- Oxidative Phosphorylation (ETC/ATP Synthase)
Metabolic Pathways
- A sequence of chemical reactions in a cell
- Determined by enzymes
1). Glycolysis (anaerobic)
Investment Step
- Glucose (6-carbon sugar) conversion to 2 Pyruvate (3-carbon sugar)
- Inputs:
- 1 glucose
- net 2 ADP
- 2 NAD+
- Outputs:
- net 2 ATP
- 2 NADH
- 2 Pyruvate
- Occurs in cytoplasm in both Euk/Pro
Kinase
- Enzyme that transfers phosphates
- Hexokinase: glucose + ATP —-> glucose-6-phosphate + ADP
- Pyruvate Kinase: PEP + ADP —> ATP + Pyruvate
Substrate Level Phosphorylation
moving a phosphate from a substrate directly to ADP to make ATP; requires an enzyme (kinase)
2). Pyruvate Oxidation (anaerobic)
Transition Step
- Used in aerobic and anaerobic respiration
- generates 2 NADH and 2 Acetyl CoA
- CoA = coenzyme A (small organic vitamin cofactor)
- 2 CO2 is also made
- Eukaryotic
- Mitochondria
- Prokaryotic
- Cytoplasm
3). Krebs Cycle
- Used in aerobic and anaerobic respiration
- Generates 2 ATP, 6 NADH, 2 FADH2
- 2 Cycles per glucose molecule
- Lots of NADH generated
- Release 4 CO2
- Eukaryotic
- Mitochondria
- Prokaryotic
- Cytoplasm
4). Oxidative Phosphorylation (Electron Transport Chain/ATP Synthase/Chemiosmosis)
Aerobic
- Series of molecules in a membrane that transports electrons
- 1 NADH = 3 ATP ——– 10 NADH = 30 ATP
- 1 FADH2 = 2 ATP ——– 2 FADH2 = 4 ATP
- 34 ATP made
- oxygen (terminal electron acceptor)
- A cell always has an ETC
- allows flagella to rotate
- also used for the transport of molecules
- Eukaryotic
- Inner membrane of mitochondria
- Prokaryotic
- Across cytoplasmic membrane
NADH Dehydrogenase
- 1st protein enzyme of the ETC
- catalyzes NADH —> NAD+
Quinones
- are hydrophobic non-protein molecules that accept both electrons and protons, but only pass on electrons
Proton Motive Force
- Charge gradient/electrochemical gradient/proton gradient
Anaerobic Respiration
- Difference is the terminal electron acceptor
-
NO3- (nitrate) and SO4-2 (sulfate)
- NO2- (nitrite) and H2S (hydrogen sulfide) are reduced forms of nitrate/sulfate
-
NO3- (nitrate) and SO4-2 (sulfate)
- less ATP produced
Fermentation
- Anaerobic Respiration
- far less ATP made (2 ATP)
- Pyruvate gets reduced
-
Pyruvate Reduction
- produces alcohol and CO2
- Acid compounds
- Depends on enzyme used
-
Pyruvate Reduction
- Terminal Electron acceptor is pyruvate
