ATP is produced via:

substrate-level phosphorylation when high energy phosphate intermediates are formed and are transferred to ADP to produce ATP. Examples of this are found in glycolysis and the TCA cycle.

electron-transport phosphorylation when electrons move down the electron transport chain and chemiosmosis occurs. The electrons were picked up by electron carriers (NAD in glycolysis and the TCA cycle; FAD in the TCA cycle) and brought to the electron transport chain.

photophosphorylation as a result of photosynthesis (which also involves an electron tansport chain). Photosynthesis has light and dark reactions. In the light reactions ATP (via photophosphorylation) and reduced NADP are formed. These are used in the dark reactions (the Calvin Cycle) to reduce CO2 to the level of carbohydrate.

If we distinguish organisms based on their energy source:

Heterotrophs obtain energy from the oxidation of organic compounds (meaning that organic compounds function as e- donors). The final e- acceptor determines whether these organisms are carrying out

anaerobic respiration (if an inorganic compound other than oxygen is the terminal e- acceptor

Lithotrophs obtain energy from the oxidation of inorganic compounds (meaning that inorganic compounds function as e- donors). Two examples are

Remember -These organisms use oxygen as the terminal e- acceptor and are therefore carrying out respiration

Phototrophs obtain energy from light (light provides the energy to eject an e- from a chlorophyll molecule)

oxygenic photosynthesis is carried out by green plants, algae and cyanobacteria. These organisms split water into hydrogen (which they use for reducing power) and oxygen (which is released as O2). As a result of photosynthesis (light reactions) by these organisms ATP and reduced NADP are formed. The ATP and reduced NADP are used to reduce CO2 in what are called the dark reactions of photosynthesis (= Calvin Cycle). The reduced NADP provies the H's necessary to convert CO2 ---> CH2O (carbohydrate) and the ATP provides the energy.

anoxygen photosynthesis is carried out by purple and green bacteria. These organisms do not split water but can, for example, use H2S as an e- donor (reducing power). Oxygen is not produced in this process.

Let's put terms together using heterotrophs as an example:

these organisms are using organic compounds as e- donors and oxygen as a terminal electron acceptor

these organisms are using organic compounds as e- donors and inorganic compounds other than oxygen as a terminal electron acceptor. Note that if NO3 sserves as the terminal e- acceptor the organism is said to be carrying out denitrification and if SO4 serves as the terminal e- acceptor the organism is said to be carrying out sulfate reduction.

these organisms are using organic compounds as e- donors and organic compounds as terminal e- acceptors

SLP only (glycolysis)

Review: how many molecules of ATP are produced when an organism is carrying out aerobic respiration compared as opposed to respiration: