Energy in a Cell
PART 1
Photosynthesis and
Cellular Respiration
http://www.youtube.com/watch?v=eo5XndJaz-Y
Predictions
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Why do humans rely on plants?!!!
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What biomolecule is formed?!!!
Importance of energy

Cells need energy to be able to carry
out important metabolic functions to
sustain life.
– Ex: Active transport, cell division,
movement of flagella or cilia,
transport, and storage of proteins
Energy Transformations
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All energy originates from the sun
Radiant energy is transformed into chemical
energy (glucose) during the process of
photosynthesis.
Chemical energy (glucose) is transformed into
another chemical (ATP) during the process of
cellular respiration.
All organisms perform cellular respiration or
fermentation to produce usable energy.
Energy Transformations
Photosynthesis
Light Energy
Cellular Respiration
Oxygen
Radiant to Chemical
Glucose
Chemical to Chemical
Water
Product
Reactant
Carbon
Dioxide
Use the diagram to complete the
following sentence stem:
Based on the energy
transformations diagram, I can
infer that
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Autotrophs

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Make their own food by using the
energy from the sun
Plants, algae, some bacteria are able
to produce glucose and store it as
starch through the process of
photosynthesis
Photosynthesis: the
autotrophic process of
producing sugars by converting
light energy from the sun into
chemical energy
Photosynthesis
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Autotrophs trap electrons from light
energy in the chloroplasts of their
cells.
Use light energy to excite electrons
Use excited electrons to form the
bonds in a sugar molecule
Light Energy

6H2O + 6CO2---------- C6H12O6 + 6O2
Glucose
Photosynthesis chemical
equation
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6CO2 + 6H2O→C6H12O6 + 6O2
6 carbon dioxide molecules+ 6 water
molecules react to produce glucose +
6 oxygen molecules
Use the equation for
photosynthesis to answer
the question……

How is oxygen made during the process of
photosynthesis? In other words where does
the oxygen come from?
Chlorophyll
Photosynthesis also
requires the pigment
chlorophyll, which absorbs
specific wavelengths of
light.

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Chlorophyll – is found in the chloroplasts of
autotrophic organisms and captures light
energy from the sun
STAGES OF
PHOTOSYNTHESIS
1)
2)
3)
Energy captured from sunlight by being
absorbed by chlorophyll
Light-dependent reactions – light energy
converted to chemical energy
temporarily stored as ATP and NADPH
Calvin cycle – chemical energy powers
formation of organic compounds using
CO2
How autotrophs capture
sunlight energy
Click image to play video.
Photosynthesis
Exit Ticket:
Explain the role of CO2 in the
formation of organic
molecules.