topic 5 - cellular respiration

cellular respiration

cells harvest chemical energy stored in organic molecules and use it to generate ATP

oxidation

the removal of electrons, causes something to be more positive

reduction

gain of electrons, causes something to be more negative

glycolysis

the start of cellular respiration, occuring in teh cytosol where glucose is oxidized into 2 pyruvates. NAD+ is also reduced to form 2NADH which transports the electrons to teh ETC. Some energy is released and used to form 2 ATP by substrate level phosphorylation

pyruvate oxidation

pyruvates are oxidized into 2 molecules of Acetyl CoA and CO2 is released as waste. Electrons are transferred to NAD+ which makes NADH. Taken to the ETC

citric acid/krebs cycle

Acetyl CoA turns into citrate, which creates ATP, CO2, and electrons which are transferred to NAD+ and FAD, creating NADH and FADH2. These are shuttled to the ETC

oxidative phosphorylation

consists of ETC and chemiosmosis

ETC

located in the inner membrane, NADH is oxidized and NAD+ is recycled while the elctrons go down the chain. FADH2 does the same thing and is reduced into FAD. As the electrons move through the ETC and to the final acceptor, oxygen, energy is lost which is used to actively transport H+ across the inner membrane to create an electrochemical gradient of proteins

Chemiosmosis

H+ ions flow down their gradient back into the matrix through ATP synthase, forming ATP out of ADP + Pi. Cristae allows for more reactions ot occur because it is folded and has lots of surface area. Creates about 26-28 ATP per glucose

NAD+

the electron carrier that shuttles electrons from teh breakdown of glucose to the ETC. converted to NADH when electrons are added.

FAD

the other electron carrier, becoming involved during the Krebs cycle. Converted into FADH2

ATP Synthase

a protein hat facilitates the diffusion of H+ down their electrochemical gradient to drive the formation of ATP from ADP + Pi

anaerobic respiration

generates ATP using an ETC in the absence of oxygen. Takes place in prokaryotes who use sulfates or nitrates as their final acceptors

fermentation

generates ATP without the ETC, basically an extension of glycolysis over and over

alcohol fermentation

pyruvate is converted into ethanol

lactic acid fermentation

pyruvate is reduced by NADH to form lactate. example: muscle cells cause soreness. Lactate lowers pH in the blood.