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Root Hydrotropism, Or Any Other Plant Differential C
American Journal of Botany 100(1): 14–24. 2013. R OOT HYDROTROPISM: AN UPDATE 1 G LADYS I. CASSAB 2 , D ELFEENA E APEN, AND M ARÍA EUGENIA C AMPOS Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Col. Chamilpa, Cuernavaca, Mor. 62250 México While water shortage remains the single-most important factor infl uencing world agriculture, there are very few studies on how plants grow in response to water potential, i.e., hydrotropism. Terrestrial plant roots dwell in the soil, and their ability to grow and explore underground requires many sensors for stimuli such as gravity, humidity gradients, light, mechanical stimulations, tem- perature, and oxygen. To date, extremely limited information is available on the components of such sensors; however, all of these stimuli are sensed in the root cap. Directional growth of roots is controlled by gravity, which is fi xed in direction and intensity. However, other environmental factors, such as water potential gradients, which fl uctuate in time, space, direction, and intensity, can act as a signal for modifying the direction of root growth accordingly. Hydrotropism may help roots to obtain water from the soil and at the same time may participate in the establishment of the root system. Current genetic analysis of hydrotropism in Arabidopsis has offered new players, mainly AHR1, NHR1, MIZ1 , and MIZ2 , which seem to modulate how root caps sense and choose to respond hydrotropically as opposed to other tropic responses. Here we review the mechanism(s) by which these genes and the plant hormones abscisic acid and cytokinins coordinate hydrotropism to counteract the tropic responses to gravitational fi eld, light or touch stimuli. -
Plant:Animal Cell Comparison
Comparing Plant And Animal Cells http://khanacademy.org/video?v=Hmwvj9X4GNY Plant Cells shape - most plant cells are squarish or rectangular in shape. amyloplast (starch storage organelle)- an organelle in some plant cells that stores starch. Amyloplasts are found in starchy plants like tubers and fruits. cell membrane - the thin layer of protein and fat that surrounds the cell, but is inside the cell wall. The cell membrane is semipermeable, allowing some substances to pass into the cell and blocking others. cell wall - a thick, rigid membrane that surrounds a plant cell. This layer of cellulose fiber gives the cell most of its support and structure. The cell wall also bonds with other cell walls to form the structure of the plant. chloroplast - an elongated or disc-shaped organelle containing chlorophyll. Photosynthesis (in which energy from sunlight is converted into chemical energy - food) takes place in the chloroplasts. chlorophyll - chlorophyll is a molecule that can use light energy from sunlight to turn water and carbon dioxide gas into glucose and oxygen (i.e. photosynthesis). Chlorophyll is green. cytoplasm - the jellylike material outside the cell nucleus in which the organelles are located. Golgi body - (or the golgi apparatus or golgi complex) a flattened, layered, sac-like organelle that looks like a stack of pancakes and is located near the nucleus. The golgi body modifies, processes and packages proteins, lipids and carbohydrates into membrane-bound vesicles for "export" from the cell. lysosome - vesicles containing digestive enzymes. Where the digestion of cell nutrients takes place. mitochondrion - spherical to rod-shaped organelles with a double membrane. -
Esau's Plant Anatomy
Glossary A of on other roots, buds developing on leaves or roots abaxial Directed away from the axis. Opposite of instead of in leaf axils on shoots. adaxial. With regard to a leaf, the lower, or “dorsal,” aerenchyma Parenchyma tissue containing particu- surface. larly large intercellular spaces of schizogenous, lysige- accessory bud A bud located above or on either side nous, or rhexigenous origin. of the main axillary bud. aggregate ray In secondary vascular tissues; a group accessory cell See subsidiary cell. of small rays arranged so as to appear to be one large acicular crystal Needle-shaped crystal. ray. acropetal development (or differentiation) Pro- albuminous cell See Strasburger cell. duced or becoming differentiated in a succession toward aleurone Granules of protein (aleurone grains) the apex of an organ. The opposite of basipetal but present in seeds, usually restricted to the outermost means the same as basifugal. layer, the aleurone layer of the endosperm. (Protein actin fi lament A helical protein fi lament, 5 to 7 nano- bodies is the preferred term for aleurone grains.) meters (nm) thick, composed of globular actin mole- aleurone layer Outermost layer of endosperm in cules; a major constituent of all eukaryotic cells. Also cereals and many other taxa that contains protein bodies called microfi lament. and enzymes concerned with endosperm digestion. actinocytic stoma Stoma surrounded by a circle of aliform paratracheal parenchyma In secondary radiating cells. xylem; vasicentric groups of axial parenchyma cells adaxial Directed toward the axis. Opposite of having tangential wing-like extensions as seen in trans- abaxial. With regard to a leaf, the upper, or “ventral,” verse section. -
Plant Cells Are Eukaryotic Cells, Or Cells with a Membrane-Bound Nucleus
Plant cells are eukaryotic cells, or cells with a membrane-bound nucleus. Unlike prokaryotic cells, the DNA in a plant cell is housed within a nucleus that is enveloped by a membrane. In addition to having a nucleus, plant cells also contain other membrane- bound organelles (tiny cellular structures) that carry out specific functions necessary for normal cellular operation. Organelles have a wide range of responsibilities that include everything from producing hormones and enzymes to providing energy for a plant cell. Plant cells are similar to animal cells in that they are both eukaryotic cells and have similar organelles. However, there are a number of differences between plant and animal cells. Plant cells are generally larger than animal cells. While animal cells come in various sizes and tend to have irregular shapes, plant cells are more similar in size and are typically rectangular or cube shaped. A plant cell also contains structures not found in an animal cell. Some of these include a cell wall, a large vacuole, and plastids. Plastids, such as chloroplasts, assist in storing and harvesting needed substances for the plant. Animal cells also contain structures such as centrioles, lysosomes, and cilia and flagella that are not typically found in plant cells. Question : 2 Structures and Organelles The Golgi Apparatus Model. David Gunn / Getty Images The following are examples of structures and organelles that can be found in typical plant cells: • Cell (Plasma) Membrane - a thin, semi-permeable membrane that surrounds the cytoplasm of a cell, enclosing its contents. • Cell Wall - outer covering of the cell that protects the plant cell and gives it shape. -
Ultrastructure of Cells and Microanalysis in Malus Domestica Borkh. 'Szampion' Fruit in Relation to Varied Calcium Foliar Fe
molecules Article Ultrastructure of Cells and Microanalysis in Malus domestica Borkh. ‘Szampion’ Fruit in Relation to Varied Calcium Foliar Feeding Piotr Kowalik 1, Tomasz Lipa 1 , Zenia Michałoj´c 1 and Mirosława Chwil 2,* 1 Institute of Horticulture Production, University of Life Sciences in Lublin, Akademicka 15, 20-950 Lublin, Poland; [email protected] (P.K.); [email protected] (T.L.); [email protected] (Z.M.) 2 Department of Botany and Plant Physiology, University of Life Sciences in Lublin, Akademicka 15, 20-950 Lublin, Poland * Correspondence: [email protected] Received: 18 August 2020; Accepted: 8 October 2020; Published: 11 October 2020 Abstract: Calcium is one of the most poorly reutilized nutrients. Its deficiencies cause various physiological disturbances and, consequently, reduce the quantity and quality of yields. Reduced content of Ca2+ ions in cells leads to development of, e.g., bitter pit in apples. Efficient and instantaneous mitigation of Ca2+ deficiencies is provided by foliar feeding. There are no detailed data on the effect of foliar feeding with various calcium forms on the cell structure or on the microanalysis and mapping of this element in apple fruit cells. Therefore, we carried out comparative studies of the ultrastructure of epidermis and hypodermis cells, to assess the content and distribution of calcium in the cell wall, cytoplasmic membrane, cytoplasm, and precipitates of Malus domestica Borkh. ‘Szampion’ fruit exposed to four Ca treatments, including the control with no additional Ca supplementation (I) and foliar applications of Ca(NO3)2 (II), CaCl2 (III), and Ca chelated with EDTA (IV). -
2 the Structure and Ultrastructure of the Cell Gunther Neuhaus Institut Fu¨R Zellbiologie, Freiburg, Germany
2 The Structure and Ultrastructure of the Cell Gunther Neuhaus Institut fu¨r Zellbiologie, Freiburg, Germany 2.1 Cell Biology . .........................40 2.2.7.6 Isolating Secondary Walls . 107 2.1.1 Light Microscopy . 43 2.2.8 Mitochondria . 109 2.1.2 Electron Microscopy . 45 2.2.8.1 Shape Dynamics and Reproduction . 110 2.2.8.2 Membranes and Compartmentalization in 2.2 The Plant Cell . .........................46 Mitochondria . 112 2.2.1 Overview . 46 2.2.9 Plastids . 113 2.2.2 The Cytoplasm . 50 2.2.9.1 Form and Ultrastructure of 2.2.2.1 The Cytoskeleton . 51 Chloroplasts . 114 2.2.2.2 Motor Proteins and Cellular Kinetic 2.2.9.2 Other Plastid Types, Starches . 116 Processes . 55 2.2.2.3 Flagella and Centrioles . 57 2.3 Cell Structure in Prokaryotes ............. 119 2.2.3 The Cell Nucleus . 59 2.3.1 Reproduction and Genetic Apparatus . 122 2.2.3.1 Chromatin . 60 2.3.2 Bacterial Flagella . 124 2.2.3.2 Chromosomes and Karyotype . 63 2.3.3 Wall Structures . 125 2.2.3.3 Nucleoli and Preribosomes . 64 2.2.3.4 Nuclear Matrix and Nuclear Membrane . 65 2.4 The Endosymbiotic Theory and the 2.2.3.5 Mitosis and the Cell Cycle . 66 Hydrogen Hypothesis . ............. 125 2.2.3.6 Cell Division . 73 2.4.1 Endocytobiosis . 126 2.2.3.7 Meiosis . 73 2.4.2 Origin of Plastids and Mitochondria by 2.2.3.8 Crossing-Over . 79 Symbiogenesis . 127 2.2.3.9 Syngamy . 79 2.2.4 Ribosomes . -
Identifying Genetic Factors That Contribute to Trait Variation Among Species Is Difficult
Identifying genetic factors that contribute to trait variation among species is difficult. Weiss et al. developed a method for unbiased genome-scale mapping of trait differences and used it to work out how a range of yeast species evolved. When crossed, these yeast species produce sterile offspring, preventing the use of traditional genetic-mapping techniques. However, by reciprocal hemizygosity analysis via sequencing (RH-seq), alleles that contributed to differences in thermotolerance were spotted that diverged between two species. Surprisingly, these turned out to map to essential housekeeping genes. Thus, without taking a candidate locus approach, RH-seq allowed identification of genes responsible for traits that differ between species. Nat. Genet. 50, 1501 (2018). https://www.sciencemag.org/news/2018/11/researchers-launch-plan-sequence-66000-species-united-kingdom-s-just- start?utm_campaign=news_weekly_2018-11-02&et_rid=328058488&et_cid=2465523 The Earth BioGenome Project aims to sequence the genome of every complex organism on Earth — that’s 1.5 million species — and will probably cost $US4.7 billion. The project brings together more than a dozen existing ventures that focus on various slices of life, such as specific types of animal or the creatures of a particular country. Among the largest commitments to the effort so far is a plan by the the Wellcome Sanger Institute to decode the genomes of all the eukaryotic species in the United Kingdom, thought to number about 66,000. Nature | 3 min read https://www.sciencemag.org/news/2018/11/poop-vault-human-feces-could-preserve-gut-biodiversity-and-help-treat- disease?utm_campaign=news_weekly_2018-11-02&et_rid=328058488&et_cid=2465523 Bacterial Heme-Based Sensors of Nitric Oxide Dominique E. -
Beihefte Zum Botanischen Centralblatt
281 Manifestation^ of polarity in plant cells which apparently are without centrosomes. By W. Marquette. With plate XIII. The existiug evidence seems to favor the yiew that the for- mation of the karyokinetic spindle occurs in quite a different iasliion in the animals than in the higher plants. The most fre- qnently noted and discussed difference in the two cases is the presence of the so-called centrosome in the one and its at least apparent absence in the other. TThile the existence of the centro¬ some as a permanent cell organ in the animal cell is by no means universally admitted, the evidence for its occnrrence as such in some cases at least seems unqnestionable. The presence of the center, as Kabl and Flemming most clearly pointed out, involves a visible polar Organization in the cell; even in the resting stages the cell shows a polar Organization whose main axis is a straight line passing throngh the center and the nnclens. When the cell prepares to divide, the centrosome divides first, the two halves separate, and the spindle figure develops abont them as centers; from the beginning it is a bipolar figure. At any moment then such cells present a polar, never an isotropic strnctnre. The most tlioroughly studied animal cells in general show such an Organi¬ zation as do also many of tlie lower plants. Amongst the Algae for example Fucus1) and IHctyota2) show at least dnring the pro- cesses of division distinct central bodies, and in the apical cells of Stypocaulon3) centre is also present in the resting stages. -
The-Plant-Cell.Pdf
Levetin−McMahon: Plants II. Introduction to Plant 2. The Plant Cell © The McGraw−Hill and Society, Fifth Edition Life: Botanical Principles Companies, 2008 UNIT II CHAPTER OUTLINE Early Studies of Cells 20 The Cell Wall 22 The Protoplast 22 Membranes 22 Moving Into and Out of Cells 22 Organelles 23 A CLOSER LOOK 2.1 Origin of Chloroplasts and Mitochondria 25 The Nucleus 26 Cell Division 26 The Cell Cycle 26 Prophase 27 Metaphase 27 Anaphase 27 Telophase 27 Cytokinesis 27 Chapter Summary 30 Review Questions 30 Further Reading 30 KEY CONCEPTS 1. The Cell Theory establishes that the cell is the basic unit of life, that all living organisms are composed of cells, and that cells arise from preexisting cells. 2. Plant cells are eukaryotic, having an organized nucleus and membrane-bound organelles. 3. Substances can move into and out of cells by diffusion and osmosis. 4. Mitosis, followed by cytokinesis, results in two genetically identical daughter cells. Growth, replacement of cells, and asexual reproduction all depend on the process of cell division. CHAPTER 2 The Plant Cell Plantlets are produced by vegetative reproduction on the leaf margin of kalanchoe. Mitosis is the underlying cell division for vegetative or asexual reproduction. 19 Levetin−McMahon: Plants II. Introduction to Plant 2. The Plant Cell © The McGraw−Hill and Society, Fifth Edition Life: Botanical Principles Companies, 2008 20 UNIT II Introduction to Plant Life: Botanical Principles ll plants (and every other living organism) are com- posed of cells. In some algae and fungi, the whole A organism consists of a single cell, but angiosperms are complex multicellular organisms composed of many dif- ferent types of cells. -
Roles of Autophagy in Chloroplast Recycling☆
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Biochimica et Biophysica Acta 1837 (2014) 512–521 Contents lists available at ScienceDirect Biochimica et Biophysica Acta journal homepage: www.elsevier.com/locate/bbabio Review Roles of autophagy in chloroplast recycling☆ Hiroyuki Ishida a,⁎, Masanori Izumi b,ShinyaWadaa, Amane Makino a,c a Graduate School of Agricultural Sciences, Tohoku University, Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan b Department of Environmental Life Sciences, Graduate School of Life Sciences, Tohoku University, Katahira, Aoba-ku, Sendai 980-8577, Japan c Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency, Chiyoda-ku, Tokyo 102-0076, Japan article info abstract Article history: Chloroplasts are the primary energy suppliers for plants, and much of the total leaf nitrogen is distributed to these Received 29 July 2013 organelles. During growth and reproduction, chloroplasts in turn represent a major source of nitrogen to be re- Received in revised form 1 November 2013 covered from senescing leaves and used in newly-forming and storage organs. Chloroplast proteins also can be Accepted 7 November 2013 an alternative substrate for respiration under suboptimal conditions. Autophagy is a process of bulk degradation Available online 19 November 2013 and nutrient sequestration that is conserved in all eukaryotes. Autophagy can selectively target chloroplasts as whole organelles and or as Rubisco-containing bodies that are enclosed by the envelope and specifically contain Keywords: Autophagy the stromal portion of the chloroplast. Although information is still limited, recent work indicates that chloroplast Chloroplast recycling via autophagy plays important roles not only in developmental processes but also in organelle quality Leaf senescence control and adaptation to changing environments. -
Persea Americana, Mesocarp Cell Structure, Light and Electron Microscope Study Author(S): Flora Murray Scott, Barbara G
Persea americana, Mesocarp Cell Structure, Light and Electron Microscope Study Author(s): Flora Murray Scott, Barbara G. Bystrom and E. Bowler Reviewed work(s): Source: Botanical Gazette, Vol. 124, No. 6 (Dec., 1963), pp. 423-428 Published by: The University of Chicago Press Stable URL: http://www.jstor.org/stable/2473211 . Accessed: 09/02/2013 21:55 Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at . http://www.jstor.org/page/info/about/policies/terms.jsp . JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. The University of Chicago Press is collaborating with JSTOR to digitize, preserve and extend access to Botanical Gazette. http://www.jstor.org This content downloaded on Sat, 9 Feb 2013 21:55:02 PM All use subject to JSTOR Terms and Conditions 1963] HAIGH & GUARD-ROOT-TIP MITOSES 423 the rest of the quiescentarea, as delineatedby the boundaries of the quiescent zone on the side away CLOWES, only one division has been observed, from the root cap cannot be definedwith precision. whereasin the epidermalportion, a much smaller In the remainder of the apex behind this region, area, seven distinctdivisions are recorded.While there appears to be a fairlyuniform distribution of approximately1800 divisionshave been plotted,it divisions, with perhaps a rather higher density of would be desirableto studymany more sections in orderto clearlydefine the status of the epidermal division in the central, or "columella" area, than in region. -
Role of Endodermal Cell Vacuoles in Shoot Gravitropism
J Plant Growth Regul 2002) 21:113±119 DOI: 10.1007/s003440010047 Role of Endodermal Cell Vacuoles in Shoot Gravitropism Takehide Kato,1 Miyo Terao Morita,2 and Masao Tasaka2,* 1Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan 2Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, 630-0101, Japan ABSTRACT In higher plants, shoots and roots show negative endodermis would function as statoliths, just as in and positive gravitropism, respectively. Data from roots. surgical ablation experiments and analysis of starch The study of the sgr2 and zig/sgr4 mutants pro- de®cient mutants have led to the suggestion that vides new insights into the early steps of shoot columella cells in the root cap function as gravity gravitropism, which still remains unclear. SGR2 and perception cells. On the other hand, endodermal ZIG/SGR4 genes encode a phospholipase-like and a cells are believed to be the statocytes that is, gravity v-SNARE protein, respectively. Moreover, these perceiving cells) of shoots. Statocytes in shoots and genes are involved in vacuolar formation or func- roots commonly contain amyloplasts which sedi- tion. Thus, the vacuole must play an important role ment under gravity. Through genetic research with in amyloplast sedimentation because the sgr2 and Arabidopsis shoot gravitropism mutants, sgr1/scr and zig/sgr4 mutants display abnormal amyloplast sedi- sgr7/shr, it was determined that endodermal cells are mentation. essential for shoot gravitropism. Moreover, some starch biosynthesis genes and EAL1 are important for the formation and maturation of amyloplasts in Key words: Shoot gravitropism; Endodermis; shoot endodermis.