CELLULAR RESPIRATION
CHAPTER 7
Cellular Respiration
• Cellular respiration – the complex process in
which cells make ATP by breaking down
organic compounds.
Cellular Respiration
• Both autotrophs and heterotrophs use cellular
respiration.
• The products of cellular respiration are the
reactants in photosynthesis; conversely, the
products of photosynthesis are reactants in
cellular respiration.
Cellular Respiration
• Cellular respiration can be divided into two
stages:
1. Glycolysis- organic compounds are converted
into three carbon molecules of pyruvic acid,
producing a small amount of ATP Glycolysis is
anaerobic because it does not require the
presence of oxygen.
1. Aerobic respiration- if oxygen is present in
the cell, pyruvic acid is broken down and
NADH is used to make a large amount of ATP.
Glycolysis
• Takes place in the cytosol of cells.
• One six-carbon glucose molecule is oxidized to
form two three-carbon pyruvic acid
molecules.
• A net yield of 2 ATP molecules is produced.
Fermentation
• Aerobic respiration can only take place when
oxygen is present.
• When oxygen is not present, fermentation
occurs.
• Two types of fermentation
– Lactic acid
– Alcoholic
Fermentation
Aerobic Respiration
• Second stage of cellular respiration.
• In most cells glycolysis does not result in
fermentation. Instead when oxygen is available,
pyruvic acid undergoes aerobic respiration.
• Aerobic respiration takes place in the
mitochondria.
• Can be divided into two steps:
1. Krebs Cycle
2. Electron Transport Chain
Krebs Cycle
• Breaks down Acetyl CoA
(from pyruvic acid) to
produce CO2, hydrogen
atoms, FADH, NADH and
ATP. NADPH is not formed!
• Occurs in mitochondrial
matrix.
Electron Transport Chain
• Second stage of aerobic
respiration.
• Occurs in inner
mitochondrial membrane.
• NADH and FADH2 molecules
from the Krebs Cycle starts
the electron transport
chain.
• Transports electrons to
make LOTS of ATP (38 total
for ETC and Krebs)
• Uses oxygen as the final
electron acceptor to make
water.
Steps of the electron transport
chain
1. NADH & FADH2 give up electrons &
hydrogen atoms to the ETC
2. Electrons are passed down the chain
3. Hydrogen is pumped out of the matrix
4. ATP synthase by chemiosmosis to
produce ATP
5. WATER is produced by the combining of
the left over electrons, hydrogen and
oxygen molecules.
Electron Transport Chain
A Summary Of Cellular Respiration
Aerobic vs. Anaeorboic
PHOTOSYNTHESIS &CELLULAR
RESPIRATION REVIEW:
• http://www.youtube.com/watch?v=sQK3Yr4Sc
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• http://www.youtube.com/watch?v=00jbG_cf
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