植物生物学（BIOLOGY OF PLANTS）双语课程教案.doc

植物生物学（Biology of Plants）双语课程教案Botany: An IntroductionIn the Introduction Well study the following topics: Evolution of Plants Evolution of Communities The Appearance of Human Beings By the time you finish studying the introduction, you should be able to answer the following questions:1. What are the main factors thought to be responsible for the origin of life on Earth, and what evidence supports the hypothesis that life arose in the ocean?2. What is the principal difference between a heterotroph and an autotroph, and what role did each play on the early Earth?3. Why is the evolution of photosynthesis thought to be such an important event in the evolution of life in general?4. What were some of the problems encountered by plants as they made the transition from the sea to the land, and what structures in terrestrial plants apparently solve those problems?5. What are bioms, and what are the principal roles of plants in an ecosystem?Evolution of Plants Life Originated Early in Earths Geologic History The planet Earth is some 4.5 billion years old, evidence obtained by analysis of carbon particles on the earth indicate that life already existed on earth 3.85 billion years ago. Evidence of the presence of life on earth as early as 3.85 billion years ago might mean that life was eliminated and reemerged. Of the nine planets in our solar system, only one , as far as we know , has life on it. This planet Earth, is visibly different from the others. From a distance, it appears blue and green, and it shines a little. The blue is water, the green is chlorophyll, and the shine is sunlight reflected off the layer of gases surrounding the planets surface.History of Life The earliest known fossils from rocks in northwestern Western Australia, dated at 3.5 billion years of age. They are about a billion years younger than the earth itself, but there are few suitable older rocks in which to look for earlier evidence of life.The Chemical Building Blocks of Life Accumulated in the Early Oceans In the 1930s, the Russian scientist Oparin proposed that vast quantities of carbon- and hydrogen-containing compounds were formed in the early atmosphere from volcanic gases composed of methane, ammonia, water vapor,and hydrogen. Miller obtained a variety of complex organic molecules similar to those that form the fundamental building blocks of all life. Stanley Miller, while a graduate student at the University of Chicago in the 1950s, used apparatus such as that shown here to simulate conditions he believed existed on the primitive Earth. Hydrogen, methane, and ammonia were circulated continuously between a lower ocean, which was heated, and an upper atmosphere, through which an electric discharge was transmitted. At the end of 24 hours, about half of the carbon originally present in the methane gas had been converted to amino acids and other organic molecules. This was the first test of Oparins hypothesis.Another theory for the origin of the chemical precursors essential to life on Earth points to comets as their source. The comet Hale-Bopp, seen here above Smith Rocks State Park, Oregon, in the spring of 1997, is made up of dirty ice that contains many of the chemical precursors of life. Some scientists believe that comets falling on the early earth in vast numbers provided the chemical “seeds” that give rise to the earths rich diversity of living organisms.Most Likely, the Forerunners of the First Cells Were Simple Aggregations of Molecules When dry mixtures of amino acids are heated at moderate temperature, polymers known as thermal proteinoids are formed. Each of these polymers may contain as many as 200 amino acid subunits. When the polymers are placed in water solution and maintained under suitable conditions, they spontaneously form proteinoid microspheres, as shown here. Autotrophic Organisms Make Their Own Food, but Heterotrophic Organisms must Obtain Their Food from External Sources Heterotroph:living organism that obtains its energy from carbohydrates and other organic material. All animals and most bacteria and fungi are heterotrophic. Autotroph: organisms that use inorganic substances as energy sources and carbon dioxide as a carbon source. A modern heterotroph and a photosynthetic autotroph. (a) A fungus, Coprinus atramentaris, growing on a forest floor in California. (b) Large flowered trillium(Trillium grandiflorum,大花延龄草), one of the first plants to flower in spring in deciduous woods of eastern and midwestern North American. Photosynthesis Altered Earth Atmosphere, Which in Turn Influenced the Evolution of Life The increase in oxygen level which resulted from photosynthesis had two consequences: Ozone in the out layer of atmosphere. By about 450 million years ago, organisms, protected by the ozone layer, could survive in the surface layers of water and on the land. Increase in free oxygen, which was accompanied by the first appearance of eukaryotic cells.The Seashore Environment Was Important in the Evolution of Photosynthetic Organisms The waters near seashore were rich in nitrates and minerals carried down from the mountains by rivers and streams and scraped from the coasts by the ceaseless waves. Multicellular photosynthetic organisms were better to maintain their position against the action of the waves and to anchor their bodies to the rocky surfaces. A fossil of Cooksonia, one of the earliest and simplest plants known, from the Late Silurian period(414-408 million years ago). Cooksonia consisted of little more than a branched stem with terminal sporangia, or spore-producing structures. Multicellular photosynthetic organisms anchored themselves to rocky shores early in the course of their evolution.Colonization of the Land Was Associated with the Evolution of Structures to Obtain Water and Minimize Water Loss Diagram of a young broad bean(Vicia faba)plant, showing the principal organs and tissues of the modern vascular plant body.Evolution of Communities Some examples of the enormous diversity of biological communities on Earth. (a)Fall color in the eastern deciduous forest. Note the presence of a few evergreens among the hardwoods. (b)View of the tundra, locality unknown. (c) In Africa, savannas are inhabited by huge herds of grazing mammals, such as these zebras. The tree in the foreground are acacia（刺槐）. (d)The tropical rainforest, shown here in Costa Rica, is the richest, most diverse biome on earth, with at least two-thirds of all species of organisms on Earth found there. (e) Deserts typically receive less than 25 centimeters of rain per year. Here in the Sonoran desert in Arizona, the dominant plant is the giant saguaro cactus.Adapted for life in dry climate, saguaro cactuses have shallow, widespreading roots and thick stems for storing water. Mediterranean climates are rare on a world scale. Cool, moist winters, during which the plants grow, are followed by hot, dry summers, during which the plants become dormant. Shown here is a pine-oak chapparal photographed on Mount Diablo in California.California Wildfire in 2003Ecosystem Are Relatively Stable, Integrated Units That are Dependent upon Photosynthetic Organisms Biological communities, along with the nonliving environment of which they are part, are known as ecological systems, or ecosystems. The stability of an ecosystem may be disrupted by non-human (Fire, flood) factors or by human (Urbanization, pollution) factors. A large disturbance (Volcanic eruption or prolonged drought) may alter or destroy an entire ecosystem.Appearance of Human beings The clockface of biological time, which shows when important events in the Earths past would have occurred if the Earths 4.5-billion year history were condensed into one day. Life first appears relatively early, sometime before 6:00 a.m. on a 24-hour time scale. The first multicellular organisms do not appear until the early evening of that 24-hour day, and Homo, the genus to which humans belong, is a late arrival-at about 30 seconds to midnight.Plant Biology Includes Many Different Areas of Study Plant physiology: the study of how plants function, how they capture and transform energy and how they grow and develop. Plant morphology: the study of the form of plants. Plant anatomy the study of plant internal structure. Plant taxonomy and systematics Involving the naming and classifying of plants and studying the relationships among them. Plant cytology: the study of plant cell structure, function, and life histories. Plant genetics: the study of heredity and variation. Molecular biology: the study of the structure and function of biological molecules. Economic botany: the study of past, present, and future uses of plants by people. Plant ecology: the study of the relationships between plant organisms and their environment. Paleobotany: the study of the biology and evolution of fossil plants.Chapter 1 Introduction to the Plant Cell In this Chapter, well study Development of the Cell Theory Prokaryotic Cells and Eukaryotic Cells The Plant Cell: An Overview Plasma Membrane Nucleus Chloroplasts and Other Plastids Mitochondria Peroxisomes Vacuoles Oil Bodies Ribosomes Endoplasmic Reticulum Golgi Complex Cytoskeleton Flagella and Cilia Cell Wall Plasmodesmata By the time you finish studying this chapter, you should be able to answer the following questions:1. How does the structure of prokaryotic cell differ from that of a eukaryotic cell?2. What are the various types of plastids, and what roles does each play in the cell?3. What are the principal components of the endomembrane system, and what role does each play in that system?4. What is meant by the cytoskeleton of the cell, and with what cellular processes is it involved?5. How do primary cell walls differ from secondary cell wall?Cell theory All living organisms are composed of one or more cells; The chemical reactions of a living organism, including its energy-releasing processes and its biosynthetic reactions, take place within cells; Cells arise from other cells; Cells contain the hereditary information of the organisms of which they are a part, and this information is passed from parent cell to daughter cell.Landmarks in Study of Cell Biology 1595 Jansen credited with 1st compound microscope 1626 Redi postulated that living things do not arise from spontaneous generation. 1655 Hooke described cells in cork. 1674 Leeuwenhoek discovered protozoa. He saw bacteria some 9 years later 1833 Robert Brown descibed the cell nucleus in cells of the orchid. 1838 Schleiden and Schwann proposed cell theory. 1840 Albrecht von Roelliker realized that sperm cells and egg cells are also cells. 1856 N. Pringsheim observed how a sperm cell penetrated an egg cell 1858 Rudolf Virchow (physician, pathologist and anthropologist) expounds his famous conclusion: cells develop only from existing cells 1857 Kolliker described mitochondria. 1869 Miescher isolated DNA for the first time. 1879 Flemming described chromosome behavior during mitosis. 1883 Germ cells are haploid, chromosome theory of heredity. 1898 Golgi described the Golgi apparatus. 1926 Svedberg developed the first analytical ultracentrifuge. 1938 Behrens used differential centrifugation to separate nuclei from cytoplasm. 1939 Siemens produced the first commercial transmission electron microscope. 1941 Coons used fluorescent labeled antibodies to detect cellular antigens. 1952 Gey and co-workers established a continuous human cell line. 1953 Crick, Wilkins and Watson proposed structure of DNA double-helix. 1955 Eagle systematically defined the nutritional needs of animal cells in culture. 1957 Meselson, Stahl and Vinograd developed density gradient centrifugation in cesium chloride solutions for separating nucleic acids. 1965 Cambridge Instruments produced the first commercial scanning electron microscope. 1976 Sato and colleagues publish papers showing that different cell lines require different mixtures of hormones and growth factors in serum-free media. 1981 Transgenic mice and fruit flies are produced. Mouse embryonic stem cell line established. 1998 Mice are cloned from somatic cells. 2000 Human genome DNA sequence draft.Janssens Microscope The microscope illustrated above was built by Zacharias Janssen, probably with the help of his father Hans, in the year 1595Robert Hookes Microscope This beautiful microscope was made for the famous British scientist Robert Hooke in the seventeenth century, and was one of the most elegant microscopes built during the period. Hooke illustrated the microscope in his Micrographia, one of the first detailed treatises on microscopy and imaging.The Galileo Microscope Although this seventeenth century microscope has been attributed to Galileo, a close inspection of the construction details indicates that it was made in the late 1600s, about 50 years after the famous astronomer-scientists death.COMPARISON OF CHARACTERISTICS A.EUKARYOTIC CELLS1.Possess a true “nucleus”.a.Nuclear material surrounded by a nuclear membrane.b.Nuclear material organized into paired chromosomes.c.Nuclear material (DNA) associated with proteins called histones - form the chromosomes.d.Nucleus contains nucleolus - sites of ribosome synthesis.B.PROKARYOTIC CELLS1.No “true” nucleus - nucleoid.a.No nuclear membrane.b.No paired chromosomes.c.No histones.d.No nucleolus. 2. Internal structure more complex - contains organelles - each have a specific function.3.Cytoplasmic streaming - continuous movement of the cytoplasm. 4.Cell membranes contain complex lipids - sterols (cholesterol).5.Cell walls a. Occur only on plant cells, fungi b. Composed of cellulose, chitin.6.Division occurs by mitosis, meiosis. 2. No organelles. 3. No cytoplasmic streaming. 4.Cell membrane contains no sterols. 5.Cell walls a.All typical prokaryotic cells possess cell walls. b.Composed of peptidoglycan (murein). 6.Division - binary fission.Prokaryote. A single cell from a filament of cells of a photosynthetic prokaryote, the cyanobacterium Anabaena azollae. In addition to the cytoplasmic components found in E. coli , this cell contains a series of membranes in which chlorophyll and other photosynthetic pigments are embedded. Anabaena synthesizes its own energy-rich organic compounds in chemical reactions powered by the radiant energy of the sun. Eukaryote. Chlamydomonas, a photosynthetic eukaryotic cell, which contains a membrane-bounded nucleus and numerous organelles. The most prominent organelle is the single, irregularly shaped chloroplast that fills most of the cell. It is surrounded by an envelope consisting of two membranes and is the site of photosynthesis.Eukaryote. A cell from the leaf of a maize plant. The granular material within the nucleus is chromatin. It contains DNA associated with histone proteins. The nucleolus is the region within the nucleus where the RNA components of ribosomes are synthesized. Note the many mitochondria and chloroplasts, all bounded by membranes. The vacuole, a fluid-filled region enclosed by a membrane, and the cell wall are characteristic of plant cells. As you can see, this cell closely resembles Chlamydomonas, shown in Figure 3-4.The Plant Cell: An Overview The plant cell typically consists of a more or less rigid cell wall and a protoplast. Protoplasm consists of a cytoplasm and a nucleus. The cytoplasm includes distinct, membrane bound entities (organelles such as plastids and mitochondria), systems of membranes (the endoplasmic reticulum and dictyosomes) and nonmembranous entities (such as ribosomes, actin filaments, and microtubules). The rest of the cytoplasm- the “cellular soup”, or cytoplasmic matrix, in which the nucleus, various entities, and the membrane systems are suspended is called ground substance (cytosol). The cytoplasm is delimited from the cell wall by a single membrane, the plasma membrane. In contrast to most animal cells, plant cells develop one or more liquid-filled cavities, or vacuoles, with their cytoplasm. The vacuole is bounded by a single membrane called the tonoplast.Structure of a typical plant cellMembrane Structure and Function The above figures shows the typical Unit membrane which resembles a railroad track with two dense lines separated by a clear space. These figures actually show two adjacent plasma membranes, both of which have the unit membrane structure.Diagram of Danielli and Davson s early model of the cell membrane In the early 1935, Danielli and Davson studied triglyceride lipid bilayers over a water surface. They found that they arranged themselves with the polar heads facing outward. However, they always formed droplets (oil in water) and the surface tension was much higher than that of cells. However, if you added proteins, the surface tension was reduced and the membranes flattened out.Diagram of Robertsons model of the cell membrane In 1957 Robertson noted the structure of membranes seen in the previous electron micrographs. He saw no spaces for pores in the electron micr