4.4 Overview of Cellular Respiration
Bell Ringer:
1-Describe how energy from sunlight is transferred to ATP
and NADPH. (Light-Dependent Reactions)
2-How does the Calvin cycle build sugar molecules?
(Light-Independent Reactions)
4.4 Overview of Cellular Respiration
• 1- Electrons absorb energy from the sunlight.
Some of the energy is used to pump hydrogen
ions against a concentration gradient, which then
flow back through a protein channel to enable
ATP synthase to add a phosphate group to ADP
to produce ATP. Energized electrons also
provide energy to add hydrogen ions to NADP+
to produce NADPH
4.4 Overview of Cellular Respiration
• 2- Carbon Dioxide is added to five-carbon
molecules in the cycle. Energy from ATP
and NADPH is used in a series of chemical
reactions that build the three-carbon
molecules needed to form a six carbon
molecule of glucose!
4.4 Overview of Cellular Respiration
KEY CONCEPT
The overall process of cellular respiration converts
sugar into ATP using oxygen.
4.4 Overview of Cellular Respiration
Cellular respiration makes ATP by breaking down sugars.
• Cellular respiration is aerobic, or requires oxygen.
• Aerobic stages take place in mitochondria.
mitochondrion
animal cell
4.4 Overview of Cellular Respiration
• Glycolysis must take place first.
–
–
–
–
anaerobic process (does not require oxygen)
takes place in cytoplasm
splits glucose into two three-carbon molecules
produces two ATP molecules
4.4 Overview of Cellular Respiration
Cellular respiration is like a mirror image of
photosynthesis.
• The Krebs cycle transfers energy to an electron
transport chain.
Krebs Cycle
1
mitochondrion
mitochondrion
ATP
– takes place in
matrix (area enclosed
and
by inner membrane) 6CO
mitochondrial matrix
2
– breaks down three-carbon
energy
molecules from glycolysis
2
3
– makes a small amount of
energy from
inner membrane
ATP
glycolysis
ATP
and
and
6H2 O
6O2
– releases carbon dioxide
– transfers energy-carrying
4
molecules
4.4 Overview of Cellular Respiration
• The electron transport chain produces a large amount of
ATP.
– takes place in inner
membrane
– energy transferred to
electron transport
chain
– oxygen enters
process
– ATP produced
– water released as a
waste product
1
mitochondrion
mitochondrion
ATP
matrix (area enclosed
and
by inner membrane)
6CO2
energy
Electron Transport
3
energy from
glycolysis
and
6O2
2
inner membrane
ATP
and
6H2 O
4
4.4 Overview of Cellular Respiration
• The equation for the overall process is:
C6H12O6 + 6O2  6CO2 + 6H2O
• The reactants in photosynthesis are the same as the
products of cellular respiration.