Photosynthesis & Cellular
Respiration
Chapter 6 & 7
Overview of Photosynthesis


Photosynthetic
organisms are
producers
Photosynthesis
captures energy
from sunlight to
make sugars
Structures of
Photosynthesis


Chlorophyll is a
molecule that
absorbs light energy
In plants, chlorophyll
is found in
organelles called
chloroplasts
chloroplast
leaf cell
leaf
Location of Photosynthesis


Photosynthesis in plants
occurs in chloroplasts
Photosynthesis takes
place in two parts of
chloroplasts
grana (thylakoids)
chloroplast
 Grana (thylakoids)
 Stroma
stroma
Light Dependent Reaction

The light-dependent
reactions capture
energy from sunlight
 take place in thylakoids
 water and sunlight are
needed
 chlorophyll absorbs
energy
 energy is transferred
along thylakoid
membrane then to lightindependent reactions
 oxygen is released

The light-independent reactions make sugars
 take place in stroma
 needs carbon dioxide from atmosphere
 use energy to build a sugar in a cycle of chemical
reactions

The light-dependent reactions produce ATP
Chemical Reaction

The equation for the overall process is:
6CO2 + 6H2O  C6H12O6 + 6O2
granum (stack of thylakoids)
1
chloroplast
6H2O
thylakoid
6CO2
3
6O2
2
energy
stroma (fluid outside the thylakoids)
1 six-carbon sugar
4
C6H12O6
Light Independent Reaction


The second stage of
photosynthesis uses
energy from the
first stage to make
sugars
Light-independent
reactions occur in
the stroma and use
CO2 molecules
A Photosynthesis Road Map
Chloroplast
Light
Stroma
NADP
Stack of
thylakoids
ADP
+P
Light
reactions
Calvin
cycle
Sugar used for
 Cellular respiration
 Cellulose
 Starch
 Other organic compounds
Chloroplast
Light
Photosystem II
Electron
transport
chains
Photosystem I
CALVIN
CYCLE
Stroma
Cellular
respiration
Cellulose
Starch
LIGHT REACTIONS
CALVIN CYCLE
Other
organic
compounds
A summary of the chemical processes of
photosynthesis
 Review: Photosynthesis uses light energy to make
food molecules

AN OVERVIEW OF PHOTOSYNTHESIS

The light reactions
convert solar energy to
chemical energy
 Produce ATP & NADPH

The Calvin cycle makes
sugar from carbon
dioxide
 ATP generated by the light
reactions provides the energy
for sugar synthesis
 The NADPH produced by the
light reactions provides the
electrons for the reduction of
carbon dioxide to glucose
Chloroplast
Light
NADP
Light
reactions
ADP
+P
Calvin
cycle
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

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
Cellular respiration is like a
mirror image of
photosynthesis
 The Krebs cycle transfers
energy to an electron
transport chain

Krebs Cycle
1
 takes place in




mitochondrial matrix
breaks down three-carbon
molecules from glycolysis
makes a small amount of ATP
releases carbon dioxide
transfers energy-carrying
molecules
mitochondrion
matrix (area enclosed
by inner membrane)
ATP
and
energy
6CO2
2
3
energy from
glycolysis
and
6O2
inner membrane
ATP
and
6H2 O
4

The electron transport
chain produces a large
amount of ATP
Electron Transport
 takes place in inner




membrane
energy transferred to
electron transport chain
oxygen enters process
ATP produced
water released as a
waste product
1
mitochondrion
ATP
matrix (area enclosed
by inner membrane)
energy
2
3
energy from
glycolysis
and
6O2
and 6CO
inner membrane
2
ATP
and
6H2 O
4
Overall Reaction


The equation for the overall process is:
C6H12O6 + 6O2  6CO2 + 6H2O
The reactants in photosynthesis are the
same as the products of cellular
respiration