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63 Cards in this Set
- Front
- Back
Periderm |
Replaces the epidermis in older regions of stems and roots. |
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Epidermis
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The outer layer of tightly packed cells in nonwoody plants. |
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Cuticle
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A waxy epidermal coating in leaves and most stems that prevents water loss. |
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Trichomes
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Highly specialized cells found in plant shoots. |
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Xylem
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Conducts water and dissolved minerals upward from the roots to the shoots. |
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Phloem
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Transports sugars and organic materials from where they are made to the area where they are needed. |
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Stele |
The vascular tissue of a root or stem. |
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Pith |
Ground tissue that is internal to the vascular tissue in plants. |
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Cortex
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Ground tissue that is external to the vascular tissue. |
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Parenchyma cells
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Made of thin walls and lack secondary walls. They perform the metabolic functions of the plant. |
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Collenchyma cells
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Support young parts of the plant shoot.
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Schlerenchyma cells
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Supporting cells that are more rigid than collenchyma cells. |
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Lignin
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A strengthening polymer that accounts for 1/4 of the mass of wood. |
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Tracheids
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Occur in the xylem of all vascular plants. |
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Sieve-tube elements
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The part of the phloem where nutrients are passed through. They lack a nucleus and ribosomes etc. |
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Lignin
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A strengthening polymer that accounts for 1/4 of the mass of wood.
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Tracheids
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Occur in the xylem of all vascular plants.
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Indeterminate growth
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Growth that occurs throughout the lifecycle of an organism--particularly in plants. |
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Meristems
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Unspecialized tissues that divide when the conditions are right. |
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Determinate growth
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Organs/organisms that stop growing after they reach a certain size.
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Apical meristems
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Provide cells that enable plants to grow in length. |
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Primary growth
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Plant growth in length.
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Lateral meristems
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Provide cells that enable plants to grow in thickness.
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Secondary growth
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Plant growth in thickness. |
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Vascular cambium
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Adds layers of secondary xylem and secondary phloem in secondary growth. |
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Cork cambium
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Replaces the epidermis with periderm in secondary growth.
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Annual plants
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Plants that complete their life cycle in one year. |
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Biennial plants
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Plants that require two growing seasons to complete their life cycle. |
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Perennial plants
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Plants that live for many years. |
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Endodermis
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The innermost layer of the cortex. It is one cell thick and forms a boundary with the vascular cylinder. |
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Pericycle |
The outermost cell layer of the vascular cylinder.
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Leaf primordia |
Cow-horn shaped projections that emerge from the sides of the shoot apical meristem. |
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Apical dominance
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The closer an axillary bud is to an active apical bud, the more inhibited it is. It can be overruled by photosynthetic priorities.
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Intercalary meristems
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Structures that allow damaged leaves to regrow, particularly in monocots.
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Stomata
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Pores in the epidermis of plants that allows exchange of carbon dioxide and oxygen between the surrounding air and the photosynthetic cells in the leaf. They also promote evaporative loss of water. |
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Guard cells
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The cells that plank stomata. They consist of two specialized epidermal cells and regulate the opening and closing of the pore. |
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Mesophyll
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Ground tissue in a leaf which is sandwiched between the upper and lower epidermal layers.
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Palisade mesophyll
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Mesophyll that has one or more layers of elongated parenchyma cells on the upper part of the leaf. |
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Spongy mesophyll
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Mesophyll that is below the palisade mesophyll. They are more loosely arranged allowing carbon dioxide and oxygen to flow around the cells. |
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Bundle sheath
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A layer of cells that regulates the movement of substances between the vascular tissue and the mesophyll. |
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Vascular rays
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Radial files of mostly parenchyma cells that connect the secondary xylem and phloem. They move nutrients between the secondary xylem and phloem, store carbohydrates, and aid in wound repair.
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Dendrochronology
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The science of analyzing tree growth ring patterns.
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Heartwood
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Layers of xylem that no longer transport water and minerals and are closer to the center of the stem or root.
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Sapwood
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The newer, outer layers of xylem that still transport xylem sap.
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Suberin
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The waxy, hydrophobic material that mature cork cells deposit.
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Lenticels
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Small, raised areas that create space between cork cells to allow for the exchange of gasses with the outside air.
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Bark
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All tissues external to the vascular cambium.
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Development
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The specific series of changes by which cells form tissues, organs, and organisms.
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Developmental plasticity
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The ability to alter form in response to local environment conditions.
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Growth
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An irreversible increase in size.
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Morphogenesis
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The process that gives a tissue, organ, or organism its shape and determines the positions of cell types.
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Cell differentiation
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The process by which cells with the same genes become different from one another.
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Preprophase band
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Microtubules in the cytoplasm become concentrated into a ring.
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Symmetry of cell division
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The distribution of cytoplasm between daughter cells.
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Asymmetrical cell division
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One daughter cells receives more cytoplasm than the other during mitosis.
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Polarity
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The condition of having structural or chemical differences at opposite ends of an organism.
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Pattern formation
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The development of specific structures in specific locations.
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Hox genes
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Genes that encode transcription factors and are critical for the proper number and placement of embryonic structures.
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Arabidopsis
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Root hair cells and hairless epidermal cells.
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Phase changes
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The morphological changes that arise from plant developmental activity in the shoot apical meristem.
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Floral meristem identity genes
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The genes that are switched on to transition from vegetative, indeterminate growth to flowering growth in plants.
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Plant organ identity genes
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Genes that encode transcription factors that regulate the development of characteristic floral patterns.
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ABC hypothesis
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A hypothesis that proposes that three classes of genes direct the formation of the four types of floral organs. |