Chapter 8 & 9
Catabolic pathways
Cellular respiration
aerobic respiration
anaerobic respiration
requires oxygen; so it is consumed as a reactant along with other organic fuels
does not need oxygen
cellular respiration is referred of aerobic respiration
food provides the fuel for respiration
redox: oxidation and reduction
oxidation - loses electrons
reduction - Gails electrons
organic compound + O2 --> CO2 + water+ energy
breaking own cellular respiration is exergonic b/c it breaks down glucose
the electrons that are released stored in organic molecules is used to synthesize ATP
where oxygen, CO2 and ATP is produced
four steps: 1 glycolysis, 2 transition reaction, 3 citric acid cycle, 4 ETC
use ETC but nor fermentation
takes place in prokaryotic organisms that lives in environment w/o oxygen
electrons carry NADH to the ETC, which regenerates to NAD+
the final electron acceptor is oxygen
the final electron acceptor is another molecule that is electronegative w less than oxygen
exergonic reaction
endergonic reaction
releases energy/ electrons
it gained electrons
the 1st step is glycolysis
catabolic pathway - it breaks down glucose
makes 2 pyruvic acid
the process happens outside the mitochondria, it happens in the cytoplasm
doesn't use oxygen bc it doesn't use O2 until ETC
slips one glucose into two pyruvate
alcoholic fermentation and lactic fermentation
alcoholic fermentation - pyruvate is converted to ethanol
first it releases CO2 from pyruvate which convert to acetaldehyde
acetaldehyde is reduced by NADH to ethanol
lactic fermentation
pyruvate is reduced by NADH to form lactate as an end product, regenerating NAD+ w no release of CO2
all of the carbons are originally present in glycolysis
the 2nd step is transition reaction
it starts in the cytoplasm and then moves into the mitochondria
it does not require oxygen
for every 3 carbons (pyruvate) it adds a coenzyme A and releases a CO2
when a coenzyme A is added it converts the pyruvate to acetyl CoA
it does not convert into acetyl CoA until it is inside the mitochondria
3rd step is citric acid cycle (herbs cycle)
a serious of aerobic organisms that releases stored energy through oxidation of acetyl CoA
where majority of ATP is made
happens in the mitochondria matrix
brings in 2 NAD+ and converts it into 2 NADH and 2 H+
ADP and energy then converts into ATP
FAD then coverts into FADH+
does not require oxygen
4th step is electron transport chain
happens in the inner membrane of mitochondria
it needs oxygen
a series of complexes that transfer electrons
it comes from electron donors to electrons acceptor via redox
chemiosmosis
the movement of ions across the membrane, down their electrochemical gradient
oxidative phosphorylation
a molecule from ATP that is being phosphoryaled
it is a major source for the production of ATP
energy coupling
transfer energy from catabolism to anabolism
free energy is coupled or functionally linked to the energy needed another chemical reaction
energy is releases by ATP hydrolysis
or energy from exergonic to endergonic
endergonic - consumes energy to build molecules
exergonic-releases energy
loses energy; Gibbs free energy is negative
gains energy - give free energy is positive
enzyme substrate complexes
a substrate binds to an active site of an exams converts it to an enzyme-substrate complex
the substrates causes conformational change or shape changes
it is only a temporary molecule when is comes to a perfect contact w its substrate
it causes enzymes to catalyze which lowers the activation energy required for the reaction to start