6. Capacity to do work
Kinetic energy
› energy of motion
› moving objects perform work by imparting motion to› moving objects perform work by imparting motion to
other matter
› Water gushing through dam turn turbines
› Light to power photosynthesis› Light to power photosynthesis
Potential energy
St d› Stored energy
› Based on location or structure
› Energy stored in molecules
7. Totality of an organism’s chemical process
CATABOLIC PATHWAYSCATABOLIC PATHWAYS
Release energy by breaking down complex
molecules to simpler compoundsmolecules to simpler compounds
Cellular respiration
ANABOLIC PATHWAYS
Consume energy to build complicated molecules
f i lfrom simpler ones
Protein synthesis from amino acids
8.
9. ExergonicExergonic
› Proceeds with a net release of energy
› occurs spontaneously
› “Downhill”
Endergonic
› Absorbs free energy from its surrounding
St f› Stores free energy
› Non spontaneous
› “Uphill”› Uphill
10. Transfer of electrons from a LESS
electronegative substance to a MORE
l i b ?electronegative substance?
Downhill reaction or Uphill reaction?
13. When ATP is hydrolyzed, it releases free
energyenergy
Th ll l th tThe cell couples the energy to
endergonicendergonic processprocess by transferring a
phosphate group from ATP to somephosphate group from ATP to some
other molecule
PHOSPHORYLATIONPHOSPHORYLATION
Phosphorylated intermediate- morePhosphorylated intermediate more
reactive (less stable)
20. “The wholesale release of energy from fuel
is difficult to harness efficiently for
i k”constructive work”
Cellular respiration does not oxidize
glucose in one step
21. Three metabolic stages
1. Glycolysisy y
› Cytosol
› Breakdown of glucose into 2 molecules of pyruvate
2. Krebs cycle
› Mitochondrial matrix
› Decomposes pyruvate into CO› Decomposes pyruvate into CO2
3. Electron Transport chain and oxidative
phosphorylationphosphorylation
› Inner membrane of mitochondria
24. Oxidative phosphorylation
› Electrons are passed from one electron acceptor› Electrons are passed from one electron acceptor
to another
› Energy released at each step is used to make ATP
› Accounts for 90% of ATP generated
41. Fermentation enables some cells toFermentation enables some cells to
produce ATP without the use of oxygen
Cellular respiration
› Relies on oxygen to produce ATPyg p
In the absence of oxygenyg
› Cells can still produce ATP through
fermentation
42. GlycolysisGlycolysis
› Can produce ATP with or without oxygen, in
aerobic or anaerobic conditionsaerobic or anaerobic conditions
› Couples with fermentation to produce ATP
43. Fermentation consists ofFermentation consists of
› Glycolysis plus reactions that regenerate NAD+,
which can be reused by glyocolysiswhich can be reused by glyocolysis
45. D i l ti id f t tiDuring lactic acid fermentation
› Pyruvate is reduced directly to NADH to form
lactate as a waste productlactate as a waste product
46.
47.
48. Both fermentation and cellular respiration
› Use glycolysis to oxidize glucose and other
organic fuels to pyruvate
49. Fermentation and cellular respiration
› Differ in their final electron acceptor
Cellular respiration
› Produces more ATP
55. Mitochondria ChloroplastMitochondria
Electrons from food
molecules (oxidation
Chloroplast
Do not need food to
make ATPmolecules (oxidation
of food molecules)
make ATP
light drives theg
electron flow down an
ETC and H+ gradient
formationformation.
