Download Photosynthesis and Cellular Respiration

Cellular Respiration
• Cellular Respiration: Converts food into energy (ATP)
Nutrients + oxygen  water + ATP + CO2
• There are three stages of Cellular Respiration
– Glycolysis
• Anaerobic – does not require oxygen
– Citric Acid (Krebs) Cycle
• Aerobic – does require oxygen
– Electron Transport Chain
• Aerobic – does require oxygen
Glycolysis
• Glycolysis: Splits one glucose into two pyruvic acids
• This reaction takes place in the cytoplasm of the cell
(anaerobic reaction)
• Produces:
– 2 pyruvic acid molecules
– 2 ATP molecules
– 2 NADH (electron carrier)
• Occurs in the Michondria
• Requires Oxygen
Citric Acid/Krebs Cycle
CO2 is
released
Pyruvate
(enzyme) from
Glycolysis
fuels the cycle
CO2 is
released
NADH and FADH2
flavin adenine
dinucleotide (energy
carrying enzyme
molecules) are
released
ATP is
released
Electron Transport Chain
• Electron Transport Chain uses the electron carriers
(NADH and FADH2) to pass electrons down the
protein chain and slowly release energy that is used to
form ATP and water molecules
• Electron Transport Chain transfers the most energy
Cellular Respiration
ATP
Glucose
Pyruvic
Acid
NADH
and FADH2
Oxygen
Glycolysis
Citric Acid Cycle
(Krebs Cycle)
Pyruvic
Acid
CO2
NADH
and FADH2
Water
Electron Transport Chain
ATP
ATP
Cellular Respiration Equation
C6H12O6 + 6O2
Glucose made in
photosynthesis
by plants or
consumed by
animals
Used in
Glycolysis
Oxygen from the
atmosphere
Used in Electron
Transport Chain
6CO2 + 6H2O + energy
Carbon
Dioxide –
waste
product of
the Citric
Acid Cycle
Water –
released
from
Electron
Transport
Chain
ATP released from
Glycolysis, Citric
Acid Cycle, and
Electron Transport
Chain
Between 34-36 ATP can be made with this process.
This ATP can be used by the cells for cellular metabolism.
Fermentation
• When oxygen is not available anaerobic
respiration, fermentation, can follow glycolysis
in order to continue to produce energy.
• This is not as efficient as aerobic respiration and
produces far fewer ATP’s
• Two types of fermentation:
– Lactic acid Fermentation
– Alcoholic Fermentation
Lactic acid Fermentation
• Lactic acid fermentation occurs in muscle cells
during strenuous exercise when a lot of energy
is required and oxygen is scarce (oxygen debt).
Glucose  pyruvic acid  lactic acid + ATP
• The lactic acid is transferred from the muscle
cells to the liver where it will be converted
back into pyruvic acid
• The build up of lactic acid in the
muscles is what causes them to
be fatigued and sore.
Alcoholic Fermentation
• Yeast and some bacteria cells are capable of
alcoholic fermentation during which glucose is
broken down to release CO2 and ethyl alcohol
Glucose  pyruvic acid  alcohol + CO2 + ATP
• The bubbles formed by the CO2 make
bread rise
• The alcohol released
turns grape juice into wine
Photosynthesis vs. Cellular Respiration
Photosynthesis
Stores Energy as glucose
Cellular Respiration


Releases Energy in glucose
Occurs in Living Cells
Uses an Electron Transport
Chain
Occurs in Plant Cells






Occurs in Animal Cells
Releases Oxygen


Releases Carbon Dioxide
Creates Energy

Neither!