cellular respiration
how living things get energy out of organic molecules and convert one type of organic molecule to another
-oxidation of organic molecules
chemical reactions involve
the gain and loss of electrons from atoms
oxidation- is the loss of electrons
reduction- is the gaining of electrons
LEO GER
L-ose E-lectrons O-xidation G-ain E-lectrons R-eduction
to make the release of energy useful:
- electrons are gradually removed from organic molecules
- energy in individual electrons is gradually reduced and
- energy is converted to a useful form (ATP)
what % of the energy released from cellular respiration is stored in ATP
40% , the remainder stored in heat
three stages of respiration
- glycolsis
- krebs cycle
- electron transport chain and chemiomosis
electrons carriers are
used to transport electrons from one place to another
how to know which one is oxidized or reduced ?
90% of the time one with H is reduced
most ATP is made through
chemiosmosis
electron transport chain
- it is a series of proteins on a membrane
- accepts electrons from electron carrier
- reduces the energy of electrons
- energy from the electrons is used to actively transport H+ across the membrane
- oxygen is final electron acceptor
chemiosmosis
- the H gradient created by the electron transport chain is a form of potiential energy
- H+ crosses the membrane through an enzyme (ATP synthase) enzyme because ase ending
- the kinetic energy in the movement at H+ is converted to potential energy in ATP
glycolysis
splitting of glucose into 2 molecules of pyruvic acid
produces ATP and NADH
glycolysis stages
1- energy input stage
2- energy harvesting stage
involves two sets of reactions for gycolysis
- energy input- addition of phosphates to gluclose (requires energy)
- energy removal- removal of phosphates (onto ATP) removal of electrons
2 ways ATP is made in respiration
- chemiosmosis
2. substrate level phosphorylation: phosphate is transferred from an organic molecule to ADP
pyruvic acid is converted into
a two carbon compound before it enters the krebs cycle
krebs (citric acid) cycle
- electrons transferred to NAD and FAD
- CO2 is produced
- ATP is produced by substrate level phosphorilation
in non- photosynthetic organisms CO2 is
a waste product
without what does the electrons transport chain stop operating
O2
what happens when no O2 is available
fermentation: oxidation of organic compounds in the absence of oxygen
glycolysis produces ATP and NADH
without O2 glycolysis results in a buildup of NADH (and a drop in NAD)
two fermentation processes remove the electrons from NAHD using pyruuvic acid
- alcohol fermentation
2. lactic acid fermentation
prokaryotes can use a number of electron accpetors in addition to O2
metals
sulfur compounds
organic molecules
this allows them to live in an O2, free environment
overall energy production
each NADH yields 3 ATP
for NADH produced outside the inner mitochondrial membrane: active transport into the mitochondria requires 1 ATP
each FADH2 yields 2 ATP
overview of cellular respiration
-living things store energy in electrons in the bonds of organic molecules
-the energy in electrons cam be increased or decreased
-respiration involves the removal of electrons from an organic molecules and the gradual reduction in the energy of each electrons
-the energy released from electrons is used to make ATP
-NAD and FAD act as electron carriers
respiration occurs in three stages
-gycolysis involves energy input and energy release phases. it produces ATP, NAHD, amd pyrvic acid
-the krebs cycle involves the production of CO2, ATP, NADH, and FADH
-most of the atp in cellular respiration is produced during chemiosmosis
-oxygen is the final electrons acceptor in the electron transport chain
