Chapter 8
Photosynthesis
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What you know
• All living things are made of cells
• All cells contain DNA
• Eukaryotes have a nucleus and many
organelles within their cells
• Organelles need energy
• Plants make energy from the sun
• Other organisms consume energy
• Mitochondria convert energy
Energy and Life
• Energy is the ability to do work
• Cars, appliances, lights, and
computers depend on energy to
function
• Living things require energy, too
• Even as we sleep, energy is
being used!
Autotrophs and
Heterotrophs
• Some organisms, such as plants can
make their own food by using the
sun’s energy
• What are these organisms called?
• Autotrophs, or producers
• Other organisms obtain energy from
food they consume
• What are these organisms called
• Heterotrophs, or consumers
Forms of Energy
• Energy comes in many forms, such
as electrical, light, heat, and
chemical.
• Living things use chemical fuels.
• One of the principal chemical
compounds that cells use to store
and release energy is called
adenosine triphosphate, or ATP.
• ADP, or adenosine
diphosphate is another
compound that has 2
phosphate groups instead
of 3.
Stored Energy vs.
Released Energy
• When living things store energy, a
phosphate group is added to an ADP
molecule, making it ATP. When
energy is needed, the bond is broken
between the 2nd and 3rd phosphates,
and energy is released.
• ATP powers many activities in the
cell including active transport,
synthesis of proteins, and moving
organelles through the cell.
Overview of
Photosynthesis
• Photosynthesis uses the energy
of sunlight to convert water and
carbon dioxide into high-energy
sugars and oxygen.
• The sugars are then converted
into complex carbohydrates
such as starches.
• What plant organelle carries out
photosynthesis?
• Chloroplasts
Light and Pigment
• Plants gather the sun’s energy
with light absorbing molecules
called pigment.
• The primary pigment is called
chlorophyll.
• What is the equation for
photosynthesis?
• 6CO2 + 6H2O → C6H12O6 +6O2
Inside a Chloroplast
• Saclike membranes called
thylakoids
• Arranged into stacks called
grana
• Space surrounding the stacks is
called stroma
Photosynthesis occurs
in two parts:
• Light-dependant reactions,
which occurs in the thylakoids.
• Calvin cycle (light independent
reactions), takes place in the
stroma
• Remember: Photosynthesis
uses sunlight to convert water
and carbon dioxide into oxygen
and high-energy sugars.
Review
What organelle in the cell
carries out the process of
photosynthesis?
• Chloroplast
What organelle in the cell
converts the glucose
molecule into ATP?
• Mitochondria
What must occur to
change ATP to ADP?
• The bonds between the 2nd and
3rd phosphate groups must be
broken, energy is released.
What are organisms that
make their own food
called?
•Autotrophs
What are organisms that
cannot make their own
food called?
•Heterotrophs
What are the
components of an ATP
molecule?
•Adenine
•Ribose
•Phosphates
ATP is the abbreviation
for what molecule?
• Adenosine Triphosphate
Cellular Respiration
Chapter 9
Cellular Respiration
–The process that
releases energy by
breaking down food
molecules in the
presence of
oxygen.
Occurs in three
stages:
• Glycolysis
• Krebs
Cycle
• Electron
Transport
Chain
Glycolysis
•One molecule of
glucose is broken in
half, producing 2
molecules of pyruvic
acid.
•Occurs in the
cytoplasm.
Krebs Cycle
• Pyruvic acid is broken down
into carbon dioxide in a
series of reactions.
• Energy is produced in the
form of NADH, FADH2, and
ATP.
• Occurs in the mitochondria.
Electron Transport
Chain
• Uses high-energy electrons
produced in the Krebs Cycle
to convert ADP into ATP.
• Occurs in the mitochondria.
• The total process of cellular
respiration makes 36
molecules of ATP per 1
molecule of glucose.