Transcript Plant Photosynthesis

Plant Respiration & Photosynthesis
•Most leaves provide a large surface for the absorption
of light energy.
•Roots are structures specialized for anchorage,
nutrient storage, and absorption of water and soluble
salts for the conduction of materials to the stem.
•Root hairs increase the surface area of the root for
absorption of water and minerals.
•The major functions of the outer layer of the leaf
(EPIDERMIS) and the waxy covering of the epidermis
(CUTICLE) are to protect the internal tissues of the leaf
from water loss, invading fungi, and physical injury.
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•Most photosynthesis in leaves takes place in the PALISADE LAYER of
the upper epidermis.
•The exchange and circulation of gases occurs in the spongy layer, which
has many air spaces. This spongy airy area also carries on
photosynthesis.
•In most leaves, chloroplasts are present in the palisade layer, spongy
layer, and in the guard cells.
•Openings in the cuticle and
Epidermis are called STOMATES.
Their size
is regulated by the Guard cells.
Stomates allow the exchange of O2,
CO2, and H2O between the external
environment and the internal
air spaces.
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Most photosynthesis occurs in the leaf.
There are 2 guard cells
per each stoma
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Conducting tissue, located in the veins of the leaves, carries water and
minerals to the photosynthesizing cells (XYLEM) and distributes food to
the other plant organs (PHLOEM).
Hint: Water and Xylem both have 5 letters; Phloem and Food “both have the f sound”
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Photosynthesis
The ability of most green plants and certain Monerans and Protists
to manufacture organic compounds from inorganic raw materials is
Autotrophic Nutrition. These organisms are called self feeders
because they make their own food. They are also called
producers.
The principle autotrophic process is called photosynthesis.
Heterotrophic Nutrition refers to organisms that get their food from
other sources and cannot make their own food. They are also
called consumers.
Photosynthesis is the process where light energy is converted into the
chemical energy of organic molecules.
Photosynthesis is the process that releases most of the oxygen that is
in our air.
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Most cells that carry on
photosynthesis contain
chloroplasts. These
chloroplasts contain
green pigments called
chlorophylls.
Chlorophyll absorbs light
energy.
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In the chloroplasts, carbon dioxide and water are used
in the formation of simple sugars (carbohydrates) and
oxygen.
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Photochemical (LIGHT )Reactions
In photosynthesis, two major sets of reactions occur: Light and Dark
reactions.
Light reactions occur within the layered membranes in the chloroplasts.
Stacks of these membranes, called the grana, contain all of the enzymes
and pigments necessary for the light reactions.
Some of the energy absorbed by the chlorophyll pigments is used to split
the water molecules, producing hydrogen atoms and oxygen gas. This
process is called photolysis.
In addition to the production of oxygen gas, ATP is also produced in the
chloroplasts during light reactions. ATP stands for Adenosine
Triphosphate
We will discuss what ATP is during cellular respiration.
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Carbon-Fixation (DARK) Reactions
These reactions occur within the chloroplasts in the
stroma.
Stroma is the dense solution outside of the grana.
The enzymes necessary for the dark reactions are found
in the stroma.
Hydrogen atoms from the light reactions and the carbon
dioxide molecules form a three-carbon sugar called
PGAL, from which glucose is synthesized (created).
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