Transcript Cellular Respiration - Kent City School District

Cellular Respiration
“What a Sweet Process!”
Cellular Respiration

Defined as: the process by which
mitochondria break down food molecules to
produce ATP

C6H12O6 + 6O2  6CO2 + 6H2O + energy (ATP)
Review of Mitochondria
Structure
 Smooth outer
Membrane
 Folded inner
membrane
 Folds called Cristae
 Space inside cristae
called the Matrix
Copyright Cmassengale
Cellular Respiration
 Can be broken into 3 steps:
Glycolysis
2)Krebs (Citric Acid) Cycle
3)Electron Transport Chain
1)
Glycolysis (Glyco-lysis)
 Takes place in cytoplasm
 Breaks down glucose (6 C’s) into 2
compounds each with 3 C’s (Pyruvic
acid)
 Net ATP= 2
 This step is necessary b/c
glucose is too big to fit through
the mitochondrial membrane!
Krebs Cycle
 Pyruvic acid enters the mitochondria
Pyruvic acid is broken down to produce 2
ATP molecules and CO2
Electron Transport Chain
 Takes place on the inner
mitochondrial membrane, makes
32 ATP
 Creates a pool of H+ ions that
create a gradient (outer matrix)
 ATP Synthase forms ATP
 Water is made from e-, H+, and O2
to keep the chain going!
Why the three steps?
 If cellular respiration took place in
just one step, all of the energy from
glucose would be released at once
and most of it would be lost in the
form of light and heat.
 It can't simply start a fire - it has to
release the explosive chemical
energy in food molecules a little bit
at a time.
 Aerobic Process = Requires Oxygen
 Anaerobic Process = Doesn’t Require
Oxygen
 The preferred pathway is aerobic in humans,
it yields far more ATP! (38 vs. 2)
 ATP production depends on oxygen
availability!
Review
Alternate Route!
 Fermentation: anaerobic (no O2)
process that continues making ATP
temporarily in the cytoplasm until
oxygen is available again
 2 types:
 Lactic Acid: can occur in mostly
animals and some bacteria
 Alcoholic: occurs in yeast cells
Lactic Acid Fermentation
 Makes only 2
ATP!
 Builds up lactic
acid in muscles
making the
“burning”
sensation while
working out!
Alcoholic Fermentation
Makes only 2 ATP
Also gives off CO2 and Alcohol!
Used for making bread dough
rise during baking
Also, used for wine,
champagne, etc.
Final Result
In the presence of
oxygen, cellular
respiration breaks down
glucose to get up to 38
ATP (66% efficient)
A different look…
 http://www.qcc.cuny.edu/BiologicalScie
nces/Faculty/DMeyer/respiration.html
 http://www2.nl.edu/jste/electron_trans
port_system.htm
 http://www.wiley.com/legacy/college/b
oyer/0470003790/animations/electron_
transport/electron_transport.htm