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• Identify four phyla of plants ? • Which of these phyla are vascular? Questions • HL Question Compare two types of meristem found in plants. HL -- Compare the growth found at the apical & lateral meristems Apical Meristems • Found at the rips of roots and shoots • Responsible for primary growth • Extensions of roots and shoots • Growth of new organs and developing basic shape of plant Lateral Meristem • Found in the cork cambium and vascular cambium • Responsible for primary secondary growth • New vascular tissue and producing woood Outline two differences in structure between monocotyledonous and dicotyledonous plants. (2) Structure Monocotyledonous Dicotyledonus leaf parallel veins branched (net of) veins; seed one cotyledon two cotyledons; floral parts in multiple of 3 scattered vascular bundles floral parts in multiple of 4 or 5; ring of vascular bundles around central pith; adventitious roots branched tap roots; flower stem root Monocot/ Dicot Scavenger Hunt • Using a camera phone finds as many examples of Dicotyledon & monocotlyledon LEAVES and FLOWERS as you can. • EACH leaf & flower MUST BE A DIFFERENT SPECIES OF PLANT. • You have 10 minutes. …. Plant Adaptation PowerPoint • Name of adaptation • Picture of Adaptation • Description of how function relates to structure Draw the diagram below, label the vascular cambium, secondary xylem, secondary phloem and cork cambium Draw the diagram of a dicot stem below and label the following features: Cortex, epidermis, pith, cambium, xylem, phloem, vascular bundle • Draw a diagram to the left and in your diagram of a dicotolydenous stem label the xylem, phloems, cambium, vascular bundle Identify the labels A-F and define their function Which one is a monocot and which one is a dicot? Which one is a monocot and which one is a dicot? Which one is a monocot and which one is a dicot? DICOT STEM ? MONOCOT STEM? CONTROL OF PLANT GROWTH. • IDENTIFY THE HORMONE THAT CAUSES PLANTS TO BEND TOWARDS LIGHT • IDENTIFY THE NAME OF THE GROWTH/ TROPISM OF PLANTS TOWARDS LIGHT • IDENTIFY WHERE AUXIN IS PRODUCED. • WHERE ON A STEM DOES AUXIN CONCENTRATE (SUNNY SIDE OR DARK SIDE) • AT THE CELLULAR LEVEL WHAT DOES AUXIN DO Opening Questions HIGH LEVEL • Outline the adaptations of plant roots for absorption of mineral ions from the soil. (5) Outline the adaptations of plant roots for absorption of mineral ions from the soil. (5) • Large surface area of roots allow for rapid absorption of mineral ions; • Branching of roots increases surface area; root hairs of epidermal cells increase surface area; • Mineral ions are absorbed by roots via active transport through membranes of the root hair cells • root hair cells have carrier protein/ion pumps (in their plasma membrane); • there are many mitochondria in root (hair) cells • The mitochondria in root hair cells provide ATP for active transport ; • Roots have connections with fungi in the soil/fungal hyphae which increase absorption of minerals from soil; • Describe the process of water uptake and movement in roots. • (6) • • • • • • • • • oot hair / root branching / cortex cells add surface area; plants actively transport minerals from soils; creating a solute gradient within the root; that draws water into the root through osmosis; (most) water travels through the apoplastic pathway / through cell walls; movement is by capillary action; some water travels via the symplastic pathway / through cell cytoplasm (and plasmodesmata); apoplast water cannot bypass Casparian strip of endodermis; enters xylem within vascular cylinder / stele;6 maxPlus up to [2] for quality)[20] • Explain the process of water uptake and transport by a plant.(Total 8 marks) Explain the process of water uptake and transport by a plant.(Total 8 marks) • • • • • • • • • • • • Roots have a large / increased surface which allows for rapid uptake of water Root hairs increase the surface area; water is absorbed in roots by osmosis; Water travels into roots cells from soil because solute concentration inside the root is higher than in the soil / outside; Solute concentration is higher in roots than soil b/c solutes (mineral ion) are actively transport into the root; Water travels through the cortex cells of roots through apoplastic and symplastic pathways apoplastic route/ pathway of water is through the cell walls of the root cells(and intercellular spaces); symplastic route of water is through the cytoplasm (and plasmodesmata) of roots cells; Water is carried up stem by xylem (vessel elements / tracheids); Before entering the xylem water has to pass through cytoplasm of endodermis / Casparian strip blocks water; water movement up the xylem due to pulling force / transpiration pull from leaves; water movement up the xylem is also due to cohesion between water molecules; Outline the adaptations of plant roots for absorption of mineral ions from the soil. (5) 5. Mineral ions are absorbed by active transport; 6. For example, root hair cells have carrier protein/ion pumps (in their plasma membrane) • • which allows them to pump H+ out to displace cations in the soil and creates a electro-chemical gradient (membrane potential) between inside of the cell and outside. This membrane potential provides energy to get the cations to be absorbed by the root cells via facillated diffusion in carrier proteins (similar to chemiosmosis in respiration and photosynthesis); Ions pumps allow for specific cation minerals to be pumped (actively transported) inside the plant cell 7. And (many) mitochondria in root (hair) cells • Provides energy (ATP) to allows hydrogen ions to be actively pumped out of cell via ion pumps and to allow ions to be actively pumped in via specific ion pumps; Outline adaptations of xerophytes. (4) Outline adaptations of xerophytes. (4) • xerophytes are plants that live in dry conditions; • Xerophytes have reduced leaves/spines to prevent water loss (by transpiration); • They have rolled leaves to prevent water loss / stomata on the inside / sunken stomata; • They have thick waxy cuticle/hairs on leaves to prevent water loss (by transpiration); • They have reduced stomata to prevent water loss (by transpiration) / stomata on one side of leaf; • They have deep/widespread roots to obtain more water; special tissue for storing water; • They have alternative forms of photosynthesis such as CAM where they take in carbon dioxide at night via their open stomatas to prevent water loss • Outline the role of phloem in active translocation of sugars from source to sink. (6) • Translocation is the transport of sugar from photosynthetic tissue (leaves) to some other organ (i.e. roots/ buds/ stems/ seed/ fruits) for sugar storage. • Sugar/ sucrose is transported through the phloem. • The phloem is made up of living cells called sieve tube members and companion cells. • Sucrose is loaded into sieve tubes by the companion cells via active transport. • An increase in sucrose concentration in sieve tube cells cause water to diffuse into phloem via osmosis, • This sucrose and water inside the phloem causes a positive pressure which cause phloem sap (water and sugar solution) to move in the phloem towards the sink/ organ of sugar storage. • At the sink, sucrose is actively transported into sink cells and is chemically converted to starch. • When sucrose leaves phloem and enters sink cells, water diffuses out of the phloem and back to the xylem, and water is recycled. IB ASSESSMENT STATEMENT •9.3.1 Draw and label a diagram showing the structure of dicotyledonous animal-pollinated flower and plants. Copyright Pearson Prentice Hall Flower structure Stigma Style Ovary Petal Anther Sepal Filament © 2008 Paul Billiet ODWS Structure of Flowers •Parts of a Typical Flower Stamen Stigma Anther Filament Style Ovary Ovary Petal Sepal Ovule Copyright Pearson Prentice Hall Carpel IB ASSESSMENT STATEMENT 9.3.3 Draw and label a diagram showing the external and internal structure of a named dicotyledonous seed. Know the following location and function of the following structures: Copyright Pearson Prentice Hall •Seed Structure •a) Testa protects the plant embryo and the cotyledon food stores •b) Radicle is the embryonic root •c) Plumule is the embryonic stem •d) Cotyledons contain food store for the seed •e) Micropyle is a hole in the testa ( from pollen tube fertilisation) through which water can enter the seed prior to germination •f) Scar is where the ovule was attached to the carpel wall. Copyright Pearson Prentice Hall LE 38-8a Seed coat (Testa) Radicle (Embryo root) Copyright Pearson Prentice Hall Embryo Shoots (plumule) Cotyledons Copyright Pearson Prentice Hall • Explain how flowering is controlled in long-day and short-day plants. • (7) • Flowering affected by light; • Phytochrome exists in two (interconvertible) forms/Pfr and Pr; • Pr (red absorbing/660 nm) converted to Pfr (far-red/730 nm absorbing) in red or day light; • sunlight contains more red than far red-light so Pfr predominates during the day; • There is a gradual reversion of Pfr to Pr occurs in darkness; • Pfr is active form and Pr is inactive form; • In long-day plants, flowering induced by dark periods shorter than a critical length / occurs when day is longer than a critical length; • When enough Pfr remains in long-day plants at end of short nights it will stimulate flowering; • Pfr acts as promoter of flowering in long-day plants; • short-day plants induced to flower by dark periods longer than a critical length/days shorter than a critical value; • at end of long nights enough Pfr has been converted to Pr to allow flowering to occur; • Pfr acts as inhibitor of flowering in short-day plants; • Explain the conditions that are needed to allow a seed to germinate. • (5) Explain the conditions that are needed to allow a seed to germinate. (5) • • • • • • • • • • • water needed to rehydrate the seed; gibberellin released / active after water absorbed; gibberellin needed to produce amylase; Amylase breaks down starch into maltose and then glucose. Glucose is need to do cellular respiration to provide energy for growth. Oxygen needed for (aerobic) cell respiration; warmth needed to speed up metabolism/enzyme activity; warmth indicates that it is a favourable season for germination/spring; some seeds need a cold period to stimulate germination; some seeds need fire to stimulate germination; some seeds need to pass through an animal (gut) to stimulate germination; Water movement • • • • Symplastic: Water moves from cell to cell Apoplastic: Water moves via cell walls & extra cellular spaces Water Transport into the Roots • Cells are usually interconnected via plasmodesmata. • Their plasma forms a continuum (a “symplast”). Water Transport into the Roots • Apoplastic transport is when water is transported between cells through the extra-cellular space. Three major processes that allow mineral ions to pass from soil to root 1. Diffusion (simple & Facilliated) of mineral ion & mass flow of water from the soil to the root When concentration of mineral is higher outside the root hair cells Some minerals (i.e. Potassium) need protein channel to diffuse inside roots cells (facillitated diffusion) 2. Aid provided by fungal hyphae Symbiotic relationship with a fungus…fungal filaments called hyphae increase surface area between plant and soil minerals 3. Active transport Using ATP and protein pumps to bring ions in against their conc. Gradient Using ATP and protein pumps to pump H+ ions out to create a electro-chemical gradient (chemiosmosis) and diplace positve mineral ions on clay particles. Uptake of Ions by the Roots – HOW? • Root interception – Root grows and intercepts ions • Simple diffusion – Ions move down their concentration gradient – No energy expense by plant – Example: K+ • Mass flow – Bulk flow of water into the root “carries” ions to root – Delivers N, Ca, Mg, S • Active transport – Ions move against their concentration gradient – Requires a specific protein “pump” in the cell membrane – Energy expense by plant HL-- Describe how water is carried by the transpiration stream.(7) 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. Define Transpiration: transpiration is water loss (from plant) by evaporation; Define Transpirational Stream: flow of water through xylem from roots to leaves is the transpiration stream; Describe Transpiration stream: Water evaporation from spongy mesophyll cells; And (diffusion of water vapour) through stomata; Is replaced by osmosis from the xylem; water lost replaced from xylem / clear diagram showing movement of water from xylem through cell(s) (walls) to air space; water pulled out of xylem creates suction/low pressure/tension; Low pressure causes transpiration pull results; Due to hydrogen bonding/polarity of water molecules; water molecules stick together/are cohesive; xylem vessels are thin (hollow) tubes; adhesion between water and xylem due to polarity of water molecules; Adhesion and Cohension create continuous column/transpiration stream; HL You will work in Four groups today • Group 1: Give a written description & an annotated diagram of how water moves from the soil to the endodermis cells inside the root • Group 2: Give a written description & an annotated diagram of how water moves from the soil to the endodermis cells to the stomata of the leaves. • Group 3 : Give a written description & an annotated diagram how and why the stomata opens and closes. • Group 4: Give a written description and an annotated diagram identifying what factors affect the rate of transpiration and describe how and explain why they affect transpiration rate HL • 1. Describe the structure of phloem. • 2. explain how sugar moves from source to sieve • 3. Explain how a positive pressure is created in the phloem. • 4. Explain how and why this positive pressure diminishes • 5. Explain why phloems are alive and xylem cells are dead. HL Question • Plants develop brightly coloured flowers to attract animals. Which process is directly assisted by this adaptation? • A. Seed dispersal • B. Pollination • C. Fertilization • D. Germination SL Question • Distinguish between fibrous and globular proteins with reference to one example of each protein type. HL question • Explain how phytochrome affects long day plants SL QUESTION • Where in eukaryotic cells is glucose broken into pyruvate, to release energy for use in the cell? • HL question SL QUESTION • Explain the effect of substrate concentration on enzyme activity • as substrate concentration increases enzyme activity increases; • after a point, all active sites are bound to substrate / all active sites occupied; additional substrate will not lead to a greater rate of product formation at this point; • at high substrate concentration enzyme reaches maximum activity; • active sites saturated; labelled sketch-graph showing above relationship; .