Download Plant Organs

Plant Organs
Leaves: Photosynthetic Structures.
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The need to have solar energy, carbon dioxide and water to photosynthesize
Solar energy is absorbed by the chlorophyll (substance that capture sunlight)
CO2 is absorbed by the stomata (these are pores located in the stem and leaves, they do
gas exchange).
H2O is absorbed by the roots, and transported by the xylem (component of the vascular
tissue)
Leaf’s parts: Blade, Petiole and Veins.
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Blade: They are broad and have a flat portion; it absorbs sunlight.
Petiole: It arranges the leaf in a position which it can absorb the maximum sunlight
possible.
Veins: They are vascular boundless, the transport water and nutrients, in small quantities.
Stomata: Gas exchange
Mesophyll: It is located between the upper and lower levels of epidermis. (Photosynthesis
occurs in here) It is composed of parenchyma and other tissues:
Palisade Cells are columnar cells, they are tightly packed.
Spongy Cells have an irregular shape; they are not very tightly packed.
Vascular Boundless are composed of xylem and phloem.
Stem: for support and nutrients transport.
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They provide support for the plant.
They separate leaves for sunlight and air exposure.
They conduct water and dissolved minerals.
Stem’s parts: Terminal Buds, tissues and others.
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Terminal Bud: here new stems grow.
Internal: epidermis, cortex and pith and the vascular tissue.
External: nodes, internodes, leaf primordial and lateral buds.
Stems’ Secondary Growth.
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It only occurs in conifers and perennial Dicots.
It is a product of cell division and cork.
Vascular cambium in xylem and phloem.
Epidermis is replaced by cork (wood).
Roots: anchor the plant, nutrient and water absorption.
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They also store water and food molecules.
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There are two types: taproot (present in Dicots) and fibrous root system (present in
monocots)
Root parts: root cap, apical Meristem and pericycle.
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The root cap, which protects the apical Meristem.
The apical Meristem, which is composed of: other epidermis, cortex and vascular cylinder.
The pericycle, where new roots are born.
The casparian strip is present in some cells in the roots. Its function is to regulate the
entering and exiting of substances into the vascular cylinder.
Flowers: Reproductive structures of Angiosperms.
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They are produced by the sporophyte.
They form megaspores (female gametophytes) and the microspores (male gametophytes).
Flowers’ parts.
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Petals
Anther
Filament
Stigma
Style
Sepal
Ovary.
Photosynthesis.
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Is the chemical reaction into which some organisms convert sunlight into chemical energy,
into glucose bonds. (C6H12O6)
It happens in plants, algae, and some prokaryotes. Photosynthetic organisms are called
self-feeders.
The basic chemical reaction is 6CO2 + 6H2O + light energyC6H12O6+ 6O2
It occurs in the leaves, and in the chloroplasts.
Chloroplasts are plastids located inside the plant cells. They use ATP for energy.
The thylacoides are little rounded shape circles, located in the chloroplast and the stroma
is the fluid that fills up the chloroplast.
Photosynthetic reactions: Light dependant and light independent.
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The Light-dependant happens in thylacoides, and they transform sunlight into ATP and
NADPH. (these are biological molecules used by cells for energy)
The Light-independent happens in the stroma, and they transform ATP and NADPH into
Glucose.