Plants emit fluorescence during photosynthesis that is detectable by satellites in space. NASA scientists have developed a method to map this fluorescence globally using satellite data. The document then provides details on photosynthesis, including that it consists of two sets of reactions - the light reactions and Calvin cycle. It describes the light reactions in detail, including that they occur in the thylakoid membranes and produce ATP and NADPH using solar energy absorbed by chlorophyll. This energy is then used in the Calvin cycle to reduce carbon dioxide into carbohydrates.

1. Topic
7:
Photosynthesis

2. h0ps://youtu.be/1XilneV3cJI
During
photosynthesis,
plants
emit
what
is
called
fluorescence
–
light
invisible
to
the
naked
eye
but
detectable
by
satellites
orbiHng
hundreds
of
miles
above
Earth.
NASA
scienHsts
have
now
established
a
method
to
turn
this
satellite
data
into
global
maps
of
the
subtle
phenomenon
in
more
detail
than
ever
before.

3. Learning
Outcomes
1. Define
what
is
photosynthesis
2. Explain
the
light
dependent
reacHons
3. Explain
the
Calvin
cycle
4. Define
what
is
photorespiraHon
5. Compare
the
photorespiraHon
in
C3,
C4
and
CAM
plants
h0ps://www.khanacademy.org/science/biology/photosynthesis-­‐in-­‐plants

4. h0ps://youtu.be/joZ1EsA5_NY

5. 1. Define
what
is
photosynthesis
2. Explain
the
light
dependent
reacHons
3. Explain
the
Calvin
cycle
4. Define
what
is
photorespiraHon
5. Compare
the
photorespiraHon
in
C3,
C4
and
CAM
plants

6. Group
tasks
1. Write
your
definiHon
of
photosynthesis
2. Find
an
animaHon
or
video
on
photosynthesis
that
you
will
recommend
3. Prepare
an
infographic
on
photosynthesis
process

7. Flowering
Plants
as
Photosynthesis
Reactor
1. The
green
porHons
of
plants,
such
as
leaves,
carry
out
photosynthesis,
using
carbon
dioxide
and
water
as
substrates.
2. Carbon
dioxide
enters
leaves
through
stomata.
3. The
carbon
dioxide
and
water
diffuse
to
the
chloroplast,
the
site
of
photosynthesis.

8. Chloroplasts
1. The
chloroplast
has
a
double
membrane
that
surrounds
the
liquid
stroma.
2. The
stroma
contains
numerous
flat
thylakoid
disc
arranged
in
stacks
called
grana.
3. The
chlorophyll
pigments
imbedded
in
the
thylakoid
membranes
absorb
solar
energy
during
photosynthesis.

9. The
Photosynthesis
Process
CO2
+
H2O
(CH2O)
+
O2
oxida>on
reduc>on
gain
of
hydrogen
atoms
loss
of
hydrogen
atoms
Solar
energy
Produce/genera>ng
glucose
Release/waste
product

10. Two
Sets
of
Reac>ons
1. The
light
reacHons
2. The
Calvin
cycle
reacHons
/
light
independent
reacHon

12. Light
Reac>ons
Occur
in
granum
1. Chlorophyll
absorbs
solar
energy,
which
energizes
electrons.
2. ATP
is
produced
using
an
electron
transport
chain.
3. NADP+,
a
coenzyme,
accepts
electrons
to
become
NADPH.
4. ATP
&
NADPH
produced
in
thylakoid
membrane
are
used
by
the
Calvin
cycle
in
the
stroma
to
reduce
CO2
to
a
carbohydrate

13. Calvin
cycle
Occur
in
the
stroma
1. CO2
is
taken
up
by
one
of
the
substrates
in
the
cycle.
2. ATP
and
NADPH
from
the
light
reacHons
reduce
CO2
to
a
carbohydrate.

14. Calvin Cycle/Light Independent
Reaction/Dark reaction

15. 1. Define
what
is
photosynthesis
2. Explain
the
light
dependent
reacHons
3. Explain
the
Calvin
cycle
4. Define
what
is
photorespiraHon
5. Compare
the
photorespiraHon
in
C3,
C4
and
CAM
plants

16. LIGHT
REACTIONS

17. The
light
reac>ons

18. The
electron
pathway
of
the
light
reac>ons
• The
light
reacHons
consist
of
an
electron
pathway
that
produces
ATP
and
NADPH.
• The
pathway
uses
2
photosystems
to
complete
the
light
reacHons.
– Photosystem
I
(PS
I)
– Photosystem
II
(PS
II)

19. A
photosystem
(PS
I
&
PS
II)
consists
of
3
major
parts.
1.
Pigment
complex,
as
an
antenna
/light
harvesHng
antenna:
ConsisHng
300
chlorophyll
molecules
and
40
beta
carotenes
and
other
accessory
pigments
acHng
as
a
light
harvesHng
antenna
2.
Reac>on
center;
a
special
chlorophyll
pigment
*
Pigment
complex
(light
antenna)
gathering
solar
energy
and
passed
photon
from
one
pigment
to
the
other
un9l
in
a
reac9on
center
(chlorophyll
a)

20. 3.
Electron
acceptor
molecules:
Photon
is
absorbed
by
one
of
the
pigment
molecules
and,
!
transfers
that
energy
to
neighboring
molecules,
!
unHl
it
reaches
the
acHon
center
where,
!
the
energy
is
used
to
transfer
an
energeHc
electron
to
an
electron
acceptor.

21. Photosystem
II
contains
the
same
kind
of
chlorophyll
a
as
Photosystem
I
but
in
a
different
protein
environment
with
an
absorpHon
peak
at
680
nm.
(It
is
designated
P680).
Light
reac>ons:
PS
II
&
PS
I

23. Light
reac>ons:
PS
II
1. When
PS
II
absorbs
solar
energy,
electron
in
reacHon
center
of
PS
II
become
energized
electrons
2. Energized
electron
are
passed
to
electron
acceptors.
3. PS
II
splits
a
water
molecule
to
recover
the
electrons
passed
to
the
electron
acceptors
(at
electron
transport
chain),
releasing
O2
+
H2O
4. The
electron
acceptors
send
the
energized
electrons
down
an
electron
transport
chain.
5. Energy
is
released
and
stored
in
the
form
of
H+
gradient
in
thylakoid
lumen
6. Electron
transport
chain
establishes
an
energy
gradient.
7. Electron
transport
chain
carries
electron,
pass
electron
from
one
to
the
other
8. As
the
electrons
are
passed
down
an
electron
transport
chain,
energy
is
released
and
stored
in
the
form
of
a
hydrogen
ion
(H+)
gradient.
9. This
H+
gradient
is
used
later
in
photosynthesis
to
produce
ATP

24. ATP
Produc>on
1. During
photosynthesis,
the
thylakoid
space
becomes
an
H+
reservoir.
2. The
H+
ions
that
fill
this
reservoir
come
from
two
sources.
1. The
oxidaHon
of
water
by
PS
II
adds
H+.
2. The
flow
of
electrons
through
the
electron
transport
chain
releases
energy
that
pumps
H+
into
the
thylakoid
space.
3. As
the
H+
are
released
through
an
ATP
synthase,
the
H+
flow
down
their
concentraHon
gradient
and
release
energy.
4. The
ATP
synthase
couples
that
release
of
energy
to
the
producHon
of
ATP
(ADP
+
Pi
"
ATP).

26. Light
reac>ons:
PS
I
1. When
PS
I
absorbs
solar
energy,
energized
electrons
are
passed
to
different
electron
acceptors.
2. Electrons
from
the
end
of
the
electron
transport
chain
(from
PS
II)
replace
the
electrons
from
PS
I.
3. The
electron
acceptors
pass
the
electrons
to
NADP+
to
form
NADPH.
4. Electron
from
PS
II
replace
those
lost
by
PS
I
5. When
PSI
absorbs
solar
energy,
electron
are
energized
6. Electron
energized
are
passed
to
electron
acceptor.
7. Electron
acceptor
pass
the
electron
to
series
of
electron
transport
chain,
then
final
electron
acceptor
(enzyme
that
accepts
H+)
;
NADP
8. NADP+
to
form
NADPH

28. 1. Define
what
is
photosynthesis
2. Explain
the
light
dependent
reacHons
3. Explain
the
Calvin
cycle
4. Define
what
is
photorespiraHon
5. Compare
the
photorespiraHon
in
C3,
C4
and
CAM
plants

29. CALVIN
CYCLE

30. • The
Calvin
cycle
is
a
series
of
reacHons
that
conHnually
produce
a
carbohydrate
(glucose)
from
carbon
dioxide
during
photosynthesis.

31. Calvin
Cycle
Reac>ons
The
Calvin
cycle
has
3
steps.
1. Carbon
dioxide
fixaHon
2. Carbon
dioxide
reducHon
3. RegeneraHon
of
ribulose-­‐1,5-­‐
bisphosphate
(RuBP)

32. Step
1:
Fixa>on
of
Carbon
Dioxide
1. During
the
first
step
of
the
Calvin
cycle,
CO2
from
the
air
is
a0ached
(fixed)
to
RuBP.
2. The
enzyme
for
this
reacHon
is
RuBP
carboxylase
oxygenase
(rubisco).
3. Rubisco
splits
the
resulHng
6-­‐carbon
molecule
to
form
two
3-­‐carbon
molecules
(PGA).

33. Step
2:
Reduc>on
of
Carbon
Dioxide
4. ReducHon
of
CO2
is
a
series
of
reacHons
that
uses
NADPH
and
ATP
from
the
light
reacHons
to
form
the
carbohydrate.
– NADPH
provides
electrons
for
the
reducHon.
– ATP
provides
the
energy.

34. Step
3:
Regenera>on
of
RuBP
5. The
product
of
the
Calvin
cycle
is
glyceraldehyde-­‐3-­‐
phosphate
(G3P).
6. About
1/6
of
the
G3P
is
used
to
make
glucose.
7. About
5/6
of
the
glucose
is
used
to
regenerate
the
RuBP
required
for
the
fixaHon
of
carbon
dioxide.

35. The
Importance
of
the
Calvin
Cycle
• The
G3P
molecules
produced
by
plants
can
be
used
to
make
a
wide
variety
of
chemicals
:
Eg
:
glucose,
fructose,
sucrose,
starch,
alkaloid

36. 1. Define
what
is
photosynthesis
2. Explain
the
light
dependent
reacHons
3. Explain
the
Calvin
cycle
4. Define
what
is
photorespiraHon
5. Compare
the
photorespiraHon
in
C3,
C4
and
CAM
plants

37. Photorespira>on
(also
known
as
the
oxidaHve
photosyntheHc
carbon
cycle,
or
C2
photosynthesis)
! a
process
in
plant
metabolism
where
the
enzyme
RuBisCO
oxygenates
RuBP,
causing
some
of
the
energy
produced
by
photosynthesis
to
be
wasted.
! Consumes
O2
and
organic
fuel
and
releases
CO2
! Uses
ATP
but
not
making
ATP
! Doesn’t
make
sugar
! Decreases
photosynthesis
output

38. Types
of
Photosynthesis
:
Carbon
metabolism
• Plants
are
physically
adapted
to
their
environment
• Plants
have
metabolically
adapted
photosynthesis
to
different
climates.
1. C3
plants
2. C4
plants
3. CAM
plants

39. 1.
C3
Photosynthesis
• In
areas
with
moderate
temperature
• plants
carry
out
C3
photosynthesis,
• the
first
detectable
molecule
from
the
Calvin
cycle
is
a
3-­‐carbon
compound.
• FixaHon
by
RuBP
carboxylase
(RUBISCO)
in
C3
plants:
with
CO2
&
O2.
• The
process
of
RuBP
binding
with
O2
is
known
as
photorespiraHon.
• PhotorespiraHon
reduce
photosynthesis
product
yield

40. If
the
weather
is
hot
&
dry,
C3
plant:
o
stomata
closed
o
PrevenHng
the
loss
of
H2O
o
Also
prevents
CO2
from
entering
the
leaf
o
Traps
O2
(by-­‐product
of
photosynthesis
within
the
leaf
space
in
between
spongy
mesophyll)
o C3
photosynthesis
are
necessary
adapta>on
to
minimize
photorespira>on
effect
(O2
competes
with
CO2
for
the
binding
site
on
Rubisco,
decreasing
the
efficiency
of
photosynthesis/yield
decrease)
C3

42. • C4
have
an
adapta>on
that
allow
them
to
be
successful
in
hot
dry
climates
• These
plants
carry
out/perform
C4
photosynthesis
2.
C4
Photosynthesis

43. The
anatomy
of
a
C4
plant
is
different
from
that
of
a
C3
plant.
General
leaf/C3
leaf
C4
leaf
Keong BP
Cross
sec>on
of
leaf
:
General
Versus
C4
Leaf
C4

45. • C4
photosynthesis
forming
a
4-­‐
carbon
compound.
• PEP
carboxylase
fix
PEP
(3C)
with
CO2
in
bundle
sheath
cell.
• the
first
detectable
molecule
from
the
Calvin
cycle
is
a
4-­‐
carbon
compound
(OAA)
• C4
are
able
to
avoid
the
uptake
of
O2
by
Rubisco
C4

46. • The
anatomy
of
a
C4
plant
is
different
from
a
C3
plant.
• Although
chloroplasts
are
found
in
both
the
mesophyll
and
bundle
sheath
cells,
the
Calvin
cycle
occurs
primarily
in
the
bundle
sheath
cells.
• CO2
taken
in
by
the
mesophyll
cells
is
combined
with
a
3-­‐
carbon
compound
(PEP
@
phosphoenol
phyruvate)
to
form
a
4-­‐carbon
compound
(oxaloacetate).
C4

47. The
C4
pathway
CO2
is
fixed
by
enzyme
PEP
carboxylase,
forming
a
four-­‐carbon
product
oxaloacetate
(4C)

48. The
C4
pathway
CO2
is
transported
into
bundle
sheath,
released
and
fixed
by
rubisco
(RuBP)
to
allowing
Calvin
cycle
to
proceed.
Therefore
rubisco
have
to
react
with
CO2
instead
of
O2
because
O2
is
absent.
So
no
photorespira>on
occurs

49. • Crassulacean
Acid
Metabolism
(CAM),
found
commonly
in
desert
plants,
in
warm,
arid
regions.
3.
CAM
Photosynthesis

50. CAM
• Similar
to
C4
photosynthesis,
CAM
plants
separate
CO2
fixaHon
from
the
Calvin
cycle
reacHon
to
minimize
compeHHon
from
O2.
• However
CAM
plants
separate
these
events
by
Hme.
• CO2
is
fixed
during
the
night.
• The
Calvin
cycle
reacHons
occur
during
the
day.

51. The
advantage
of
CAM
photosynthesis
involves
the
conserva>on
of
water.
• When
CAM
plants
open
their
stomata
at
night
to
obtain
CO2,
water
loss
is
minimized.
• Calvin
cycle
reacHon
occur
during
the
day
*
H2O
is
conserve,
but
CO2
cannot
enter
the
plant
CAM

52. 1. Define
what
is
photosynthesis
2. Explain
the
light
dependent
reacHons
3. Explain
the
Calvin
cycle
4. Define
what
is
photorespiraHon
5. Compare
the
photorespiraHon
in
C3,
C4
and
CAM
plants

53. Evolu>onary
Trends
• C4
plants
most
likely
involved
in
areas
with
high
light,
high
temperature,
and
low
rainfall.
• C3
plants
survive
be0er
than
C4
plants
in
temperatures
less
than
25˚C.
• CAM
plants
compete
well
with
both
C3
and
C4
plants,
parHcularly
in
arid
environments.

55. PEP
carboxylase
PEP
carboxylase

56. Summary
of
C3,
C4,
And
CAM
Reac>on