Plants A study of multicellular organisms. Cell Specialization Why do cells specialize? –Increase...
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Transcript of Plants A study of multicellular organisms. Cell Specialization Why do cells specialize? –Increase...
Cell Specialization
• Why do cells specialize? – Increase efficiency
• Division of labor
– What does efficiency look like?• Special cell shapes, sizes, type and
number of organelles, and locations in the organism
Cell Specialization• The cell is the basic unit of life• In multicellular organisms cells take on
specialized roles to perform a specialized function.– Tissues: Groups of cells that perform the
same function are called tissues
– Organ: Different types of tissues can combine together to form an organ
– System: Different organs can also work together to form a system
Specialized cells in a leaf
Specialized cells in a leaf
Tissue Types in the Leaf
• Dermal Tissue– Thin protective outer layer
• Ground Tissue– Middle layers
• Vascular Tissue– Cells specialized in transport
Epidermal Cells• Like skin cells, they form a
protective layer on the upper and lower surface of the leaf – one cell layer thick– Arranged in a flat tightly knit sheet– Transparent to allow sunlight to pass
through to cells that specialize in photosynthesis layer
Cuticle• Covers the epidermis to prevent
water loss– Waxy substance secreted by the leaf
cells– Also protects from disease causing
micro-organisms
Stomata and Guard Cells• Small openings in the epidermal
layer – Allow gasses and water to enter
and leave the leaf– Mostly found on the underside
of the leaf– Each stoma has 2 guard cells that
regulate the stoma’s size
Ground Tissue• The majority of the plant• Located under the epidermis
– In the stem• Provides strength, support
– In the roots• Food and water storage
– In the leaves • Where photosynthesis occurs
What functions occurs inside a leaf?
•Photosynthesis!!!– Leaves are flat and have a lot of
surface area so that they can absorb the suns rays and use the energy to create glucose.
• What is the chemical formula for photosynthesis?– CO2 + H2O C6H12O6 + O2
Where does photosynthesis occur?
• Chloroplasts– Contain special pigments that capture
light energy
• Therefore, leaf cells contain a lot of chloroplasts
Palisade Tissue Cells
• Cells that are structured and arranged to maximize efficiency for photosynthesis– Form a distinct layer in the leaf– Long, and narrow (look like columns)– Tightly packed– Contain many chloroplasts