WHY ARE PLANTS GREEN?
♥Pigment - acompound that absorbs light.
♥Chlorophyll - a pigment that absorbs red and blue
light (photons) so green is reflected or transmitted.
-located in the chloroplasts
√ green pigment found in the chloroplasts of plants
and photosynthetic microorganisms. It plays a
crucial role in photosynthesis, the process by which
these organisms convert light energy into chemical
energy.
√ This absorbed light energy is then used to convert
carbon dioxide and water into glucose, a type of
sugar that serves as a source of energy for the
plant
*Plants are green because the green wavelength is
reflected, not absorbed.
2 types of chlorophyll
♥Chlorophyll a - involved in light reactions in
photosynthesis
♥Chlorophyll b - assists in capturing light energy --
accessory pigment
♥Carotonoids - accessory pigments -- captures
more light energy
*red,orange and yellow
What causes the leaves to change colors during fall?
♥There are other pigments aside from the
chlorophyll pigments.
♥During the fall, the green chlorophyll pigments are
greatly reduced revealing the other pigments.
♥Carotenoids are pigments that are either red,
orange, or yellow.
PHOTOSYNTHESIS
♥Photosynthesis - It is the conversion of light energy
into chemical energy that is stored in organic
compounds (carbohydrates > glucose)
♥Used by autotrophs such as
- plants
- algae
- some bacteria (prokaryotes)
* autotrophs are organisms that can produce their own
food, using materials from inorganic sources.
Organic compounds - presence of carbon-hydrogen
bonds; if it doesn’t, then it’s inorganic.
♥Glucose - energy-rich chemical produced through
photosynthesis
- C6H12O6
♥Biochemical pathway - series of reactions where
the product of one reaction is consumed in the
next.
♥Redox Reaction reduction/oxidation
√the transfer of one or more electrons from
one reactant to another.
Two types:
1. Oxidation is the loss of e-
2. reduction is the gain of e-.
Oxidation Reaction
The loss of electrons from a substance or the gain of
oxygen.
6CO2 + 6H2O > C6H12O6 + 6O2
Carbon Dioxide glucose
Reduction Reaction
The gain of electrons to a substance or the loss of
oxygen
WHERE DOES PHOTOSYNTHESIS TAKE PLACE?
♥Plants
√ Mainly occurs in the leaves:
a. stoma - pores
b. mesophyll cells
♥Stomata (stoma)
√ Pores or tiny openings in a plant’s cuticle
through which water vapor and gases (CO2 &
O2) are exchanged between the plant and the
atmosphere.
*Stomata allow a plant to take
in carbon dioxide, which is
needed for photosynthesis.
They also enable the release of
oxygen, a byproduct of photosynthesis.
♥Chloroplast
√ Organelle where photosynthesis takes place.
♥The main form of energy from the sun is the form
of electromagnetic radiation
♥Visible radiation (white light) used for
photosynthesis
♥ROYGBIV - an acronym for the sequence of hues
commonly described as making up a rainbow
red, orange, yellow, green, blue, indigo, and violet
