Introduction to Bioenergetics

• ATP is generated by the phosphorylation of ADP
• ADP+ energy+ phosphate> ATP

Substrate level phosophorylation is the transfer of a high energy PO4- to ADP

• the transfer of electrons (oxidation) of one compound
• another (reduction)
• generate ATP
• chemiosmosis

aerobic: the final electron acceptor in the electron transport chain is molecular oxygen (O2)

anaerobic: the final electron acceptor in the electron transport chain is not O2. Yields less energy than aerobic respiration because only part of the Krebs cycle operations under anaerobic conditions. Absolute vs. Facultative

aerobic and anaerobic respiration

lipids

protein rich metabolism

• anaerobic always yields a lot less. 
• Can run parts of the Krebs cycle in anaerobic respiration, but does not run the ETC

ambient air concentration of O2 or higher is toxic

undergo anaerobic respiration but don't care if O2 is present, as long as it is present in small amounts

the breakdown of carbohydrates to release energy: glycolysis, krebs cycle, and ETC

By metabolizing glucose, they yield 36-38 ATP molecules

prokaryotes and eukaryotes are the same in terms of their process

final product of glycolysis is two pyruvate molecules, whcih will be coverted to acetyl CoA and be used for the Krebs Cycle

every organism that respires starts out with glycolysis

net gain: 2 pyruvates, 2 ATP (originally four but it uses two), and 2 NADH

• generates GTP, 2 FADH2, and 8 NADH
• 6 CO2 (and 2 ATP)

glycolysis and the CAC occur in the cytoplasm

ETC takes place in the inner leaflet of the plasma membrane

• NADH: results in 3 H+, which are pumped back 
• FADH2: associated with the cytochrome B (1.5)

1) NADH dehydrogenase: hydrolysis to NAD+ and a proton being pumped

2) Cytochrome B-C1 with FADH--> H+ and FA

3) Cytochrome oxidase= another complex that releases 2 Hydrogens

• oxidation of moelcuels liberates electrons for an ETC 
• ATP generated by oxidative phosphorylation

glycolysis: cytoplasm, cytoplasm

intermediate step: cytoplasm, cytoplasm

krebs cycle: mitochondrial matrix, cytoplasm

ETC: mitochondrial inner membrane, plasma membrane

• the location
• the reactions and pKa are all the same

• Glycolysis: 2,2,0
• Intermediate: 0,2
• Krebs: 2 GTP, 6, 2
• Total: 4, 10, 2

pentose phosphate pathway: 

entner-Doudoroff pathway

• Uses pentoses and NADPH
• Operates with glycolysis

uses 5-carbon sugars and turns them into ribose phosphate and ribulose phosphate to get to the pyruvic acid

• bacterially defined
• - produces NADPH and ATP
• - does not involve glycolysis
• - Pseudomonas, E. faecalis, E. coli
• (primary gram negative)

• 6 carbon sugars
• one atp per glucose--> 2 atp
• production of pyruvate from glucose
• only about 15 bacterial genera/ species use this

NO3- --> NO2-, N2 + H2O

SO4- --> H2S + H2O

CO32- --> CH4 + H2O

• oxygen 
• electron acceptor

• specific 
• unique products

releases energy from oxidation of organic molecuels

does not require oxygen

does not use the Krebs cycle or the ETC

uses an organic molecule as the final electron acceptor

many species have their own

4 and 5 cycles

alway less than 38 ATP produced

could be 8 or 10

produces ethyl alcohol and CO2

produces lactic acid

• homolactic: produces lactic acid only
• heterolactic: produces lactic acid and other compounds

most bacteria undergo heterolactic acid fermentation; some water, some CO2

classic glycerol formation

34 ATPs

skips glycolysis completely

38 ATP

10

protein ----(extracellular proteases)--> amino acids

-------(deamination, decarboxylation, dehydrogenation, desulfurization)----> organic acid----> krebs cycle

bacteria that break down organic minerals in the environment

breaking up waste

classic saprophyte qualities

bacteria are the only species to do this: many are archaea, with exception of one thing, they are not known to pathogens

chemolithotropy

• use oxygen as the final electron acceptor
• use inorganic compounds as a donor
• oxidize large amounts of nitrogen, sulfur, and iron containing compounds

important for cycling nitrogen and sulfur between air, water, and soil

waste products: methane, water, O2, acetate

• use sunlight to drive ATP production
• oxygenic: uses water as the electron donor
• anoxygenic: use H2 and H2S as the electron donor; no O2 produced as a water gas; do not produce oxygen or water as a waste gas

Mg core= important for electron cycling through the molecule