Transcript Cellular Respiration

Cellular Respiration
Energy
• Is the ability to do work
How do nonliving things
get energy?
• Some energy comes
from running water, wind,
or the sun
• Most of our energy
comes from burning fuels
(oil, gas, coal)
– This releases energy in
the form of heat and light
Living organisms also require
energy just like machines
•
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Flying bird
Beaver building a dam
Worm burrowing through soil
Making complex compounds from simpler
ones (synthesis)
• Transferring some molecules across the
cell membrane (active transport)
How do organisms obtain this
energy?
• Organisms rely on chemical energy stored
in their food (mostly carbohydrates)
• Cellular Respiration is the process by
which the energy stored in food inside the
cells is released
• Respiration ≠ breathing
ATP
• Adenosine triphosphate
• When the 3rd phosphate is removed and
bonded to another compound, energy is
released
• When the 3rd phosphate is removed, the
remaining molecule is called adenosine
diphosphate (ADP)
Glucose
• A simple sugar (building blocks of
carbohydrates)
• A single molecule can produce 36
molecules of ATP from ADP
Where does respiration occur?
• In cells
• In mitochondria (“powerhouse”, mighty)
Types of Respiration
• Aerobic: with oxygen
• Anaerobic: without oxygen
Do Now:
• What is the difference between
aerobic and anaerobic
respiration?
Aerobic Respiration
• Step One
– Glycolysis: process of breaking down the
glucose molecule into 2 3-carbon pyruvic acid
molecules
Occurs in cytoplasm of cells
Aerobic Respiration
• Step Two
– Pyruvic acid breaks down into carbon dioxide,
NADH, and a 2-carbon compound known as
an acetyl group
– Acetyl group combines with coenzyme A to
form acetyl CoA
Aerobic Respiration
• Step Three
– Krebs Cycle
• Series of chemical reactions
• Each turn requires 1 acetyl CoA
• Each turn produces 2 molecules of carbon dioxide
and 4 pairs of hydrogen atoms
• Each turn produces 1 ATP
Aerobic Respiration
• Step Four
– Electron Transport Chain
• Electrons from hydrogen atoms are passed along
from compound to compound
• At various places on the chain, electrons give up
some energy and molecules of ATP are formed
Net Reaction of Aerobic
Respiration
C6H12O6 + 6O2 6CO2 + 6H2O + 36 ATP
Anaerobic Respiration
• Step One
– glycolysis
• Step Two
– fermentation
2 types of fermentation
• Lactic Acid Fermentation
Lactic acid builds
up in muscles and
causes soreness
Muscle Fatigue
• During periods of prolonged physical
activity, muscle cells may use oxygen
faster than the circulatory system can
supply it
• Krebs cycle and electron transport chain
stop and lactic acid builds up
• Alcohol Fermentation
Proteins and
fats can also
feed into the
process at
various
places
Carbon Dioxide