Oral Recitation/
Recapitulation
Inside our home,
some of us love
the kitchen the
most.
The kitchen is
where most of the
food are prepared.
The word comes from Greek:
Photosynthesis
PHOTO: LIGHT SYNTHESIS: COMPOSITION
Plants make their own food as well,
but through the use of sunlight.
How is this possible?
Learning Targets
I can explain the functions of photosynthetic
pigments.
I can distinguish principal photosynthetic
pigments from accessory photosynthetic
pigments.
Photosynthesis
6CO 2 + 6H2 O C 6 H12 O 6 + 6O 2
CARBON DIOXIDE WATER GLUCOSE OXYGEN
PIGMENTS
These provides the plant their color. Pigments make things
appear to be certain colours because they absorb and
reflect different wavelengths of light.
PIGMENTS
Wavelengths of light that are not absorbed are reflected.
Reflected light gives each pigment its characteristic
color.
PIGMENTS
For instance, a red apple can be perceived as red because the pigments in the
apple’s skin absorb the other colors, leaving only the red portion of the
spectrum to be reflected. The photoreceptors of our eyes then detect these
reflected colors.
DIFFERENT TYPES OF PIGMENT
CHLOROPHYLL CAROTENOIDS ANTHOCYANIN PHYCOBILINS
Activity Time
Posted in Gclassroom
STEM E Voucher: 89531-6135
CHLOROPHYLL CAROTENOIDS ANTHOCYANIN PHYCOBILINS
CHLOROPHYLL A
it is the most common and most important
photosynthetic pigment in plants, algae, some
protists, and cyanobacteria.
This pigment absorbs violet, blue, and red light,
and reflects mainly green, so most plants appear
green to us. It participates directly in the light
reactions during photosynthesis, particularly an
important player in the light-harvesting complex of
chloroplasts.
CHLOROPHYLL B
This pigment absorbs mainly blue and orange
light but reflects olive green. Chlorophyll b does
not participate directly in light reactions, although
it conveys absorbed energy to chlorophyll a to work
in the light
reactions.
In addition, a closer look will reveal that chlorophyll a appears
bluish-green, while chlorophyll b appear yellow-green.
CAROTENOIDS
Chloroplasts also contain pigments called carotenoids,
which are various shades of red, yellow, and orange-
green light. These colors are common in leaves during
the season of fall. These yellow-orange hues of longer-
lasting carotenoids appear once the chlorophyll breaks
down reactions.
This pigment is also important in photoprotection.
Carotenoids absorb and dissipate excess light energy
that would otherwise damage the chlorophyll or interact
with oxygen to form reactive oxidative molecules that
can damage the cell.
ANTHOCYANINS
Anthocyanins are pigments found in the vacuoles of
plant cells, responsible for a wide range of colors,
including red, purple, and blue, depending on the pH of
the plant tissue. These pigments are water-soluble and
are most commonly seen in flowers, fruits, and autumn
leaves. Unlike chlorophyll and carotenoids, anthocyanins
are not directly involved in photosynthesis.
ANTHOCYANINS
Anthocyanins play a critical role in protecting plants from
environmental stresses. One of their key functions is
photoprotection, helping to reduce damage caused by
excessive light. Anthocyanins act as a "sunscreen" by
absorbing harmful blue-green and UV light, preventing
these high-energy wavelengths from damaging the plant
tissues. This protective function is especially important
under conditions of high light intensity or when plants
experience environmental stress such as drought, cold, or
nutrient deficiency.
PHYCOBILINS
Phycobilins play a crucial role in the photosynthetic
processes of aquatic organisms, especially those living in
deeper waters where light penetration is limited. These
pigments are highly efficient at capturing light in the
orange, red, and green regions of the light spectrum—
wavelengths that penetrate deeper into the water than
other colors of light, such as blue and violet. By
absorbing these lower-energy wavelengths, phycobilins
allow cyanobacteria and red algae to photosynthesize in
environments where light is scarce.
PHOTOSYNTHESIS
Light, energy and life
The word comes from Greek:
Photosynthesis
PHOTO: LIGHT SYNTHESIS: COMPOSITION
LIGHT-DEPENDENT REACTION
Light capture:
Pigments like chlorophyll absorb light energy, propelling
electrons in photosystems.
ATP generation:
The released electrons create a flow that drives ATP
synthesis, storing chemical energy.
NADPH production:
Another stream of electrons generates NADPH, an
energy and electron carrier molecule.
Oxygen release:
The water molecule splits, releasing oxygen crucial for
the atmosphere and respiration.
LIGHT-INDEPENDENT REACTION
CO2 capture:
The enzyme RuBisCO fixes carbon dioxide (CO2) into
organic compounds in the Calvin cycle.
Sugar formation:
The resulting molecules convert into sugars, utilizing ATP
and NADPH from the light-dependent phase.
RuBisCO regeneration:
Molecules enabling CO2 capture regenerate, ensuring
cycle continuity.
Readying for new cycles:
The cycle persists, creating sugars and regenerating
molecules for CO2 fixation in future iterations.
ACTIVITY TIME!
By using your Internet-
connected device, proceed to
the provided link below to
access the online interactive
about the light-dependent
reactions. You will be directed
to a platform entitled
Photosynthesis Interactive.
1. Click “Start a New Game!” at the
lower-left portion of the platform.
2. Click the “Tap or Click Here!”
option to proceed.
3. Click “Light-Dependent Reactions”
from the list presented in the main
menu. An animation and explanation
of how light-dependent reactions
happen will follow.
1. What are the key parts involved in the light-dependent
reactions?
2. What comes before the light-dependent reactions in
photosynthesis?
3. What is an electron transport chain?
4. In the simulation, how does an electron replace itself once
it moves to the electron transport chain?
5. As humans, how do we directly benefit from the photolysis
process?
6. What happens to hydrogen ions (H+) as electrons travel
through the electron transport chain?
7. After hydrogen ions move into the ATP synthase, what is
formed?
8. What occurs to the electron after it reaches photosystem 1?
9. When the electron from photosystem 1 meets NADP+, what
happens to it?
10. How does the ATP and NADPH produced during the light-
dependent reactions contribute to the overall process of
photosynthesis?
"BEFORE YOU LEAVE TODAY, WRITE
DOWN ONE QUESTION THAT TODAY’S
LESSON MADE YOU THINK OF.
Light-dependent
reactions
THANK YOU FOR
YOUR ATTENTION!
Any questions?
Graphic summary
Sunlight
Carbon
Water dioxide
NADP+
ADP
Thylakoid
Pi
Stroma
Calvin
Grana
Lamella cycle
ATP
NADPH
Oxygen Glucose
Importance
Vital energy source:
Photosynthesis converts sunlight into chemical energy,
nourishing plants and initiating food webs on Earth.
Oxygen production:
Photosynthetic organisms release oxygen as a byproduct,
sustaining the respiration of most living beings and
enriching the atmosphere with this gas.
Climate regulation:
Photosynthesis absorbs carbon dioxide, aiding in climate
change control and maintaining the balance of the
greenhouse effect.
Keyboard shortcuts
Blur Bubbles
Confetti Silence
Drum roll Curtain close
Dropping micro Timer
Keyboard shortcuts
Blur Bubbles
Confetti Silence
Drum roll Curtain close
Dropping micro Timer
