chapters 35-39. all plants… multicellular, eukaryotic, autotrophic, alternation of generations

Download Chapters 35-39. All Plants… multicellular, eukaryotic, autotrophic, alternation of generations

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Chapters 35-39 Slide 2 All Plants multicellular, eukaryotic, autotrophic, alternation of generations Slide 3 Alternation of Generations Sporophyte (diploid) produces haploid spores via meiosis Gametophyte (haploid) produce haploid gametes via mitosis Fertilization joins two gametes to form a zygote Slide 4 Angiosperms Monocots vs. Dicots named for the number of cotyledons present on the embryo of the plant + monocots - orchids, corn, lilies, grasses + dicotsdicots - roses, beans, sunflowers, oaks Slide 5 Plant Morphology Morphology (body form) shoot and root systems + inhabit two environments - shoot (aerial) + stems, leaves, flowers - root (subterranean) + taproot, lateral roots vascular tissues + transport materials between roots and shoots - xylem/phloem Slide 6 Plant Anatomy Anatomy (internal structure) division of labor + cells differing in structure and function - parenchyma, collenchyma, sclerenchyma (below) - water- and food-conducting cells (next slide) Parenchyma St: typical plant cells Fu: perform most metabolic functions Collenchyma St: unevenly thickened primary walls Fu: provide support but allow growth in young parts of plants Sclerenchyma St: hardened secondary walls (LIGNIN) Fu: specialized for support; dead Slide 7 Plant cell types Parenchyma cellsCollenchyma cells Cell wall Sclerenchyma cells Slide 8 Plant cell types Xylem Phloem WATER-CONDUCTING CELLS OF THE XYLEM Vessel Tracheids Tracheids and vessels Vessel element Pits Tracheids SUGAR-CONDUCTING CELLS OF THE PHLOEM Companion cell Sieve-tube member Sieve-tube members: longitudinal view Sieve plate Nucleus Cytoplasm Companion cell Slide 9 Water- and Food-conducting Cells XylemXylem (water) dead at functional maturity tracheids- tapered with pits vessel elements- regular tubes PhloemPhloem (food) alive at functional maturity sieve-tube members- arranged end to end with sieve plates & Companion cells Slide 10 Plant Tissues Three Tissue Systems dermal tissue + epidermis (skin) - single layer of cells that covers entire body - waxy cuticle/root hairs vascular tissue + xylem and phloem - transport and support ground tissue + mostly parenchyma - occupies the space b/n dermal/vascular tissue - photosynthesis, storage, support Slide 11 Plant Growth Meristems perpetually embryonic tissues located at regions of growth + divide to generate additional cells (initials and derivatives) - apical meristems (primary growth- length) + located at tips of roots and shoots - lateral meristems (secondary growth- girth) Slide 12 Roots A root Is an organ that anchors the vascular plant Absorbs minerals and water Often stores organic nutrients Taproots found in dicots and gymnosperms Lateral roots (Branch roots off of the taproot) Fibrous root system in monocots (e.g. grass) Figure 35.3 Slide 13 Modified Roots Many plants have modified roots (a) Prop roots(b) Storage roots (c) Strangling aerial roots (d) Buttress roots(e) Pneumatophores (a) Prop roots (b) Storage roots Slide 14 Primary Growth of Roots apical meristem + root cap + three overlapping zones - cell division - elongation - maturation Slide 15 Stems A stem is an organ consisting of Nodes (could be opposite or alternate) Internodes Slide 16 Modified Stems Rhizomes (d) Tubers (c) Bulbs Stolons (a) Storage leaves Stem Root Node Rhizome Root Slide 17 Buds An axillary bud Is a structure that has the potential to form a lateral shoot, or branch A terminal bud Is located near the shoot tip and causes elongation of a young shoot Gardening tip: Removing the terminal bud stimulates growth of axillary buds Slide 18 Primary Growth in Shoots apical meristem (1, 7) + cell division occurs + produces primary meristems - protoderm (4, 8) - procambium (3, 10) - ground meristem (5, 9) axillary bud meristems + located at base of leaf primordia leaf primordium (2, 6) + gives rise to leaves Slide 19 The leaf Is the main photosynthetic organ of most vascular plants Leaves generally consist of Blade Stalk Petiole Slide 20 Leaf Morphology In classifying angiosperms Taxonomists may use leaf morphology as a criterion Petiole (a) Simple leaf (b) Compound leaf. (c) Doubly compound leaf. Axillary bud Leaflet Petiole Axillary bud Leaflet Petiole Slide 21 Modified Leaves Tendrils Spines Storage leaves Bracts Reproductive leaves. The leaves of some succulents produce adventitious plantlets, which fall off the leaf and take root in the soil. Slide 22 Leaf Anatomy Epidermal Tissue upper/lower epidermis guard cells (stomata) Ground Tissue mesophyll +palisade/spongy parenchyma Vascular Tissue veins + xylem and phloem Slide 23 Key to labels Dermal Ground Vascular Guard cells Stomatal pore Epidermal cell 50 m Surface view of a spiderwort (Tradescantia) leaf (LM) (b) Cuticle Sclerenchyma fibers Stoma Upper epidermis Palisade mesophyll Spongy mesophyll Lower epidermis Cuticle Vein Guard cells Xylem Phloem Guard cells Bundle- sheath cell Cutaway drawing of leaf tissues(a) VeinAir spacesGuard cells 100 m Transverse section of a lilac (Syringa) leaf (LM) (c) Leaf Anatomy Slide 24 Dermal tissue Ground tissue Vascular tissue The Three Tissue Systems: Dermal, Vascular, and Ground Slide 25 Dermal Tissue Protects plant from: Physical damage Pathogens H 2 O loss (Cuticle) Slide 26 Vascular tissue Carries out long-distance transport of materials between roots and shoots Consists of two tissues, xylem and phloem Slide 27 Ground Tissue Includes various cells specialized for functions such as storage, photosynthesis, and support Pith = ground tissue internal to the vascular tissue Cortex = ground tissue external to the vascular tissue Slide 28 Secondary Growth Lateral Meristems vascular cambium + produces secondary xylem/phloem (vascular tissue) cork cambium + produces tough, thick covering (replaces epidermis) secondary growth + occurs in all gymnosperms; most dicot angiosperms Slide 29 The Vascular Cambium and Secondary Vascular Tissue The vascular cambium Is a cylinder of meristematic cells one cell thick Develops from parenchyma cells Slide 30 2 Growth As a tree or woody shrub ages The older layers of secondary xylem, the heartwood, no longer transport water and minerals The outer layers, known as sapwood Still transport materials through the xylem Slide 31 Cork Cambium Periderm protective coat of secondary plant body + cork cambium and dead cork cells - bark cork cambium produces cork cells Slide 32 Slide 33 CHAPTER 36 Slide 34 Minerals H2OH2O CO 2 O2O2 O2O2 H2OH2O Sugar Light A variety of physical processes Are involved in the different types of transport Sugars are produced by photosynthesis in the leaves. 5 Sugars are transported as phloem sap to roots and other parts of the plant. 6 Through stomata, leaves take in CO 2 and expel O 2. The CO 2 provides carbon for photosynthesis. Some O 2 produced by photosynthesis is used in cellular respiration. 4 Transpiration, the loss of water from leaves (mostly through stomata), creates a force within leaves that pulls xylem sap upward. 3 Water and minerals are transported upward from roots to shoots as xylem sap. 2 Roots absorb water and dissolved minerals from the soil. 1 Roots exchange gases with the air spaces of soil, taking in O 2 and discharging CO 2. In cellular respiration, O 2 supports the breakdown of sugars. 7 Slide 35 The Central Role of Proton Pumps Proton pumps in plant cells Create a hydrogen ion gradient Contribute to membrane potential CYTOPLASM EXTRACELLULAR FLUID ATP H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ Proton pump generates membrane potential and H + gradient. + + + + + Slide 36 Plant cells use energy stored in the proton gradient and membrane potential To drive the transport of many different cations + CYTOPLASM EXTRACELLULAR FLUID Cations (, for example) are driven into the cell by the membrane potential. Transport protein K+K+ K+K+ K+K+ K+K+ K+K+ K+K+ K+K+ K+K+ + + (Membrane potential and cation uptake + + Slide 37 Figure 37.6b (b) Cation exchange in soil. Hydrogen ions (H + ) help make nutrients available by displacing positively charged minerals (cations such as Ca 2+ ) that were bound tightly to the surface of negatively charged soil particles. Plants contribute H + by secreting it from root hairs and also by cellular respiration, which releases CO 2 into the soil solution, where it reacts with H 2 O to form carbonic acid (H 2 CO 3 ). Dissociation of this acid adds H + to the soil solution. H 2 O + CO 2 H 2 CO 3 HCO 3 + Root hair K+K+ Cu 2+ Ca 2+ Mg 2+ K+K+ K+K+ H+H+ H+H+ Soil particle Slide 38 Cotransport A transport protein couples the passage of H + to anions H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ NO 3 + + + + + + Cotransport of anions H+H+ of through a cotransporter. Cell accumulates anions (, for example) by coupling their transport to the inward diffusion Slide 39 H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ S S S S S Plant cells can also accumulate a neutral solute, such as sucrose ( ), by cotransporting down the steep proton gradient. S H+H+ + + + + + H+H+ H+H+ S + Contransport of a neutral solute Cotransport Is also responsible for the uptake of sucrose by plant cells Slide 40 Water potential Is a measurement that combines the effects of solute concentration and pressure Determines the direction of movement of water Water Flows from regions of high water potential to regions of low water potential Slide 41 Quantitative Analysis of Water Potential The addition of solutes Reduces water potential 0.1 M solution H2OH2O Pure water (a) Slide 42 Negative pressure Decreases water potential H2OH2O (d) Slide 43 Application of physical pressure Increases water potential H2OH2O (b) H2OH2O (c) Slide 44 Aquaporin Proteins and Water Transport Aquaporins Are transport proteins in the cell membrane that allow the passage of water Do not affect water potential Slide 45 Movement of fluid in the xylem & phloem is driven by pressure differences at opp

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