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lectures1and2 - Biology 114 • Lecture#1 Outline...

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Unformatted text preview: Biology 114 • Lecture #1 Outline • Introduction • Plant Cells and Tissues • Reading: Botany for Gardeners • Introduction and cells: 9-20 • Plant Cell Types: 79-82 • Tissue Handout Levels of Organization in Life Atoms Molecules Cells Tissues Cells in a plant stem Organs Organisms Oak Savanna Ecosystems Plasma Membrane • A selectively permeable barrier that regulates the movement of substances in and out of the cell. Organelle membrane bound subcellular compartment Cell Wall • Made mostly of cellulose • Function: Support and protection • All plants cells have a flexible primary cell wall • Some cells have a rigid secondary cell wall imbedded with lignin Chloroplast: specialized plastid where photosynthesis occurs grana 1 Vacuole •  Membrane enclosed fluid filled space •  Can occupy a large volume of the cell (up to 90% in a mature cell) •  Vacuole Function: 1. helps maintain cell pressure 2. storage and breakdown of cellular waste products 3. location of water soluble dyes called anthocyanins (purple and red color) Shoot apical meristem Epidermis • Outermost layer of cells • More than one cell type • Covered with a waxy cuticle layer to prevent water loss • Guard cells form stomata • Trichomes - hairs Stomata Trichomes - Leaf Hairs Ground Tissues • Present in most organs of the plant • Made of parenchyma and sclerenchyma cells, among other types 2 Ground Tissues • Parenchyma cells: • Living at maturity • Thin primary cell walls • Large central vacuole • Can take on many shapes • Function in photosynthesis, storage, and transport of food and water Ground Tissues • Sclerenchyma cells: • Dead at maturity • Thick and rigid secondary cell walls • Function in support and protection • Two types: sclereids and fibers Fibers Vascular Tissue • Continuous tissue throughout the plant in which substances are transported • Xylem and phloem Xylem Phloem • Most xylem tissue has two types of cells: tracheids and vessel elements • Function: transports water and mineral salts • Phloem function: transports sugars and other organic substances • Consists of sieve tube members - the conducting cells • Companion cells help sieve tube members function 3 Lecture Summary •  Cells: Vacuole, chloroplast, cell wall, plasma membrane •  Tissues: •  Epidermal (stomata, trichomes) •  Ground (parenchyma, sclerenchyma [fibers and sclereids]) •  Vascular (Xylem [tracheids and vessel elements] Phloem [sieve tube members and companion cells]) 4 ...
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