Lect1Plant - Bios 344: Plant Physiology Instructor: Dr....

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Unformatted text preview: Bios 344: Plant Physiology Instructor: Dr. David Higgs Introduction • Go over syllabus • Outline topics over semester • Lecture 1: Plant Cellular structures Reading Material & Out of Class Help: • Text: Introduction to Plant Physiology, 3rd Edition (2004) by William Hopkins & Norman Hüner • Handouts: Supplemental to text for some lectures • Lecture Notes: PDF’s of lectures available at http://uwp.edu/~higgs/plantphys.html • Office hours: MWR 12 – 1, best to confirm time No appointment necessary! Graded Material: Three 100 pt unit exams see syllabus for dates 300 pt Paper on Plant Physiology due Tuesday Dec. 5 100 pt Final Exam (Thurs. Dec 21, 10:30 AM) 100 pt Total Points 500 pt Attendance is necessary to understand course material, some of which will not be in text! What is Plant Physiology? Literal Definition: “Discourse on the nature of plants” - A vague & very broad definition - My Definition: “Science of how plants develop, grow, and respond to their environment at the cellular & biochemical level” What does this include? Combining what is known about: ÿ Structure and anatomy as it relates to plant function ÿ Sources of energy for growth & development ÿ Water & nutrient uptake and movement ÿ Responses to the environment (light, temp., water) ÿ Plant responses to stresses (abiotic & biotic) ÿ Aspects of plant biotechnology What types of science are involved? Plant biology/botany Plant anatomy Ecology and Environmental Biology Cell biology Inorganic & organic chemistry Biochemistry Molecular biology Lecture 1: Plant Cellular Structures (overview) • Basic Plant Cell (eukaryotic cells) • Membranes • Organelles Reading: Chapter 1 (pp 1 – 16) Basic Plant Cell (mesophyll leaf cell): Nucleus Rough endoplasmic reticulum Chloroplast Vacuole Smooth endoplasmic reticulum Cytosol = aqueous solution outside of nucleus Golgi body Peroxisomes Mitochondria Cell Wall Middle lamella Plasma membrane Primary cell wall Similar to Fig. 1.1 Lipid Bi-layer Membranes: • Mostly made of amphipathic lipid molecules - Phospholipids are major constituent - Many other, lower abundant lipids • Membrane-associated proteins: - Integral proteins (embedded within) - Peripheral proteins (on surface) • Fluid mosaic model: - lipids and proteins can move diffuse flip-flop Flex & rotate Amphipathic Phospholipid: charged No charge Similar to Fig. 1.4 Fluid Mosaic Model of Membranes: Movement within membranes: Similar to Fig. 1.17 and 1.18 Organelles present in eukaryotic plant cells: “membrane bound sub-cellular compartments” • Nucleus • Endoplasmic reticulum – rough & smooth • Mitochondria • Golgi bodies • Plastids - chloroplasts, amyloplasts & others • Vacuoles • Microbodies – peroxisomes & glyoxysomes Nucleus (electron micrograph): • Bound by double-membranes • Contains majority of cellular DNA in large, linear chromosomes • Genetic “control center” of cell • Nucleolus, site for rRNA synthesis & ribosome assembly Nuclear membrane Nucleus Nucleolus Endoplasmic reticulum (ER): • Bound by single membrane • Involved in protein trafficking & secretion • Rough ER – ribosomes bound to surface & actively translating proteins • Smooth ER – No ribosomes bound to surface Rough Smooth ER & its Complex Structure: Rough ER Smooth ER Golgi Bodies (Complex): • Bound by single membrane • Secretion of proteins via budding vesicles • Site for further protein processing & synthesis of pectin (cell wall component) Similar to Fig. 1.19 Cis cisterna Direction Of Movement Secretory vesicles Trans cisterna Mitochondria: • Bound by double membranes • Evolutionarily derived from free-living bacterium • Contain DNA/genes that encodes some of the mitochondrial proteins • Site for respiration to produce energy (ATP) from sugars • up to 250 mitochondria per plant cell Mitochondria structure: Crista Outer membrane Similar to Fig. 1.20 Plastids: • Bound by double membranes • Evolutionarily derived from free-living bacterium • Contains DNA/genes that encode some of the plastid proteins • Differentiate into specialized plastids (i.g., chloroplasts, amyloplasts, etc…) • up to 100 plastids per cell in leaves General Functions: • Photosynthesis, sugar synthesis • Mineral assimilation • Amino acid, lipid, and hormone synthesis Differentiation of Plastids • Controlled by cell-type, environment & genetic factors Fig. 1.21 Etioplast Pro-plastids: • Colorless • “young” undifferentiated plastid • often contain protein storage particles ribosome Membranes: - outer - inner Lipid deposit Protein deposit Etioplasts: • Colorless • Found in cells of dark-grown plants • Intermediate between pro- and chloroplasts Membranes Prolamellar body Chloroplasts: • Green due to chlorophyll • Found in photosynthetic organs (leaves) • Site of photosynthesis (sugar production) • Contain complex thylakoid membrane system (light absorption & energy conversion) Membranes Thylakoid membrane Stroma Leucoplasts: • Colorless • Lipid & volatile oil synthesis & storage • Found in stem & leaf trichomes (hairs) Leucoplasts from secretory trichome of peppermint leaf Membranes Lipid droplets Amyloplasts: • Colorless • Starch synthesis & storage (large grains) • Found in starch storage organs (i.e., potato tubers, grass seeds) • Statoliths, gravity sensing structures in root tips (direct growth downward) Membranes Starch grains Chromoplasts: • Bright colors (red, orange, yellow) • Concentrated carotenoids (i.e.,b-carotene) • Found in fruit (i.e., tomato, cherry), fall leaves, specialized roots (i.e., carrot), flower petals • attractants to animals to pollinate & distribute seeds Membranes Carotenoid bodies Chromoplast from Wall of cherry fruit ...
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Lect1Plant - Bios 344: Plant Physiology Instructor: Dr....

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