Chapter 35.docx

Biology 1108 Chapter 35 9/2-4/09 EU: larger cell, DNA in linear chromosome, has nucleus and organelles, larger ribosomes PRO: smaller cell, circular DNA, no nucleus or organelles, smaller ribosomes [ex: Mitochondria] Phylogeny/Evolution of Land Plants (in order) Embryo: young plant nurtured by parent Vascular Tissue: ability to transport water and food allowed plants to get large Seeds, Pollen: allow plants to reproduce in dry places Plant Cell STRUCTURE Primary cell wall: all cells have this, keep shape up, plasmodesmata connect to adjacent cells, cytoplasm continuous from cell to cell (space in between is called middle lamella which contains a clue-like pectin) Secondary cell wall: only in some, are inside the primary cell wall, walls are lignified (impregnated with hard substance called lignin, die after this process happens) Plasma cell membrane: transport Plasmodesmata: hole in wall for transportation, made of fibers of cytosol Vacuole: keep pressure up, store water, sometimes where color comes from Chloroplast: (double mem.) transform sun energy to sugars= food Mitochondria: (double mem.) burns energy, uses ATP to break down sugar (large molecules) to smaller molecules Nucleus: (double mem.) chromatin inside is loose DNA Endoplasmic Reticulum (ER): turn the DNA into proteins Golgi: protein moves to here and gets packaged ready for outside Ribosome: help process the DNA strands {cell membrane-2nd cell wall- 1st cell wall} SIMPLE TISSUES= one type of cell Parenchyma cells: no 2nd cell wall not lignified living at maturity functions= photosynthesis, food storage, pigmentation, defense Collenchyma cells: uneven primary cell wall thicknesses no 2nd cell wall alive to function functions= support for herbaceous stems ex) celery strands Sclerenchyma cells: lignified and dead at maturity {corn stem} Sclerids (?stone cells?): magnified 2nd cell wall functions= support, protection Fibers: have 2nd cell wall functions= support (reinforcements) Vessel Elements: has 2nd cell wall lignified dead at maturity large in diameter functions= water pipes (vessels stacked end on end) Tracheids: has 2nd cell wall lignified dead at maturity smaller in diameter functions= water pipe (vessels are slanted at ends to prevent oxygen bubbles) Sieve Tube Elements and Companion cells: non-lignified living at maturity functions= food transport COMPLEX TISSUES= several cell types mingled together Xylem: water; vessels that are made first like an un-stretched condense spiral and as grow older it gets stretched Phloem: sugar; companion and sieve tube SEED & SEEDLINGS Cotyledons: seeds with food stored Seed coat: protects the seed Epicotyls (leaves), Hypocotyl (embryonic shoot), Radicle (embryonic root) Monocots vs. Eudicots 1 cotyledon 2 cotyledons parallel viens net-like veins 3 leaves 4-5 leaves ORGAN SYSTEMS Shoot system: stems and leaves; SAM= shoot apical meristem (birth of new stems) Root system: roots; RAM= root apical meristem (birth of new roots) Petiole= leaf stem Bud= in axil of leaf Primordium= ?young?, where the birth of new leaves and buds come from TISSUE SYSTEM Dermal system: from protoderm Vascular system: from procambium; xylem and phloem Ground system: from ground meristem Primary tissues add length and Secondary tissues add girth YOUNG monocot STEM: Vascular bundles are scattered with no pith or cortex regions YOUNG eudicot STEM: Pith (middle with parenchyma cells) and cortex regions (parenchyma and collenchymas) separate by ring of vascular bundles; epidermis (parenchyma) surround outside Vascular bundles include (outer to inner): epidermis, bundle cap, phloem, xylem and apical meristems ROOT STRUCTURE (eudicot) Stele: central cylinder of vascular tissue (xylem in a X form and phloem surrounding) with its own endodermis and pericycle (give rise to lateral roots- bulge out of layer); parenchyma cells store food around the stele Endodermis: like a gatekeepter; has casparian strip to seal off endodermis cells Apoplast: pathway along outside of cells like water Symplast: pathway inside the cell through plasmodesmata which goes through stele to get transported throughout plant vertically {cutting board= monocot stem with vascular bundles as small circles} LEAF STRUCTURE Palisade mesophyll: upper middle Spongy mesophyll: lower middle, gas exchange Cuticle : wax to help keep water from escaping Stomat: (pore) surrounded by two guard cells and regulate amount of water being taken in Bundle Sheath: sclerenchyma fibers surround for support, xylem and phloem inside Simple leaves just have one blade from bud in axil Alternately-arranged is node with leaf then node with leaf, etc. Oppositely-arranged is node with two opposite leaves growing in same spot, etc. Compound leaves have multiple blades coming from bud in axil called leaflets MODIFIED LEAVES Tendrils: string-like vein that is stretched out to wrap around things Spines: protection/defense Bulbs: for food storage Bracts: associated with flower, looks like a leaf some leaves are adapted for capturing and digesting insects (carnivorous plants) VASCULAR CAMBIUM Cambium is a cylinder of meristematic tissue; 2nd tissue Xylem in inside (2nd xylem is wood); phloem on outside CORK CAMBIUM Inner bark: 2nd phloem, transport sugar Outer bark: grows towards inside, dead material Primary phloem, cortex, periderm (cork + cork cambium + phelloderm) Suberin: waterproof on outside of bark WOOD Woody stems have 2nd growth Dark (heart) wood: on inside for support Sap wood: on outside for water transport Have rings because difference diameter in xylem during spring (larger, more water) and fall (smaller, leaves out) Rays: allow water, mineral, sugar to move laterally; parenchyma tissue; ribbon-like Radial: through middle (quarter-sawn) Tangential: along ring; side, not middle (plain-sawn) MODIFIED STEMS Thorns: sharp for defense Cladophylls: photosynthesize, taking place of leaves Tubers: underground stems, food storage Rhizomes: underground horizontal stems