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Reproduction in Plants Which But, She Has Never Seen the Seeds We Shall Learn in This Chapter
Reproduction in 12 Plants o produce its kind is a reproduction, new plants are obtained characteristic of all living from seeds. Torganisms. You have already learnt this in Class VI. The production of new individuals from their parents is known as reproduction. But, how do Paheli thought that new plants reproduce? There are different plants always grow from seeds. modes of reproduction in plants which But, she has never seen the seeds we shall learn in this chapter. of sugarcane, potato and rose. She wants to know how these plants 12.1 MODES OF REPRODUCTION reproduce. In Class VI you learnt about different parts of a flowering plant. Try to list the various parts of a plant and write the Asexual reproduction functions of each. Most plants have In asexual reproduction new plants are roots, stems and leaves. These are called obtained without production of seeds. the vegetative parts of a plant. After a certain period of growth, most plants Vegetative propagation bear flowers. You may have seen the It is a type of asexual reproduction in mango trees flowering in spring. It is which new plants are produced from these flowers that give rise to juicy roots, stems, leaves and buds. Since mango fruit we enjoy in summer. We eat reproduction is through the vegetative the fruits and usually discard the seeds. parts of the plant, it is known as Seeds germinate and form new plants. vegetative propagation. So, what is the function of flowers in plants? Flowers perform the function of Activity 12.1 reproduction in plants. Flowers are the Cut a branch of rose or champa with a reproductive parts. -
Anoxygenic Photosynthesis in Photolithotrophic Sulfur Bacteria and Their Role in Detoxication of Hydrogen Sulfide
antioxidants Review Anoxygenic Photosynthesis in Photolithotrophic Sulfur Bacteria and Their Role in Detoxication of Hydrogen Sulfide Ivan Kushkevych 1,* , Veronika Bosáková 1,2 , Monika Vítˇezová 1 and Simon K.-M. R. Rittmann 3,* 1 Department of Experimental Biology, Faculty of Science, Masaryk University, 62500 Brno, Czech Republic; [email protected] (V.B.); [email protected] (M.V.) 2 Department of Biology, Faculty of Medicine, Masaryk University, 62500 Brno, Czech Republic 3 Archaea Physiology & Biotechnology Group, Department of Functional and Evolutionary Ecology, Universität Wien, 1090 Vienna, Austria * Correspondence: [email protected] (I.K.); [email protected] (S.K.-M.R.R.); Tel.: +420-549-495-315 (I.K.); +431-427-776-513 (S.K.-M.R.R.) Abstract: Hydrogen sulfide is a toxic compound that can affect various groups of water microorgan- isms. Photolithotrophic sulfur bacteria including Chromatiaceae and Chlorobiaceae are able to convert inorganic substrate (hydrogen sulfide and carbon dioxide) into organic matter deriving energy from photosynthesis. This process takes place in the absence of molecular oxygen and is referred to as anoxygenic photosynthesis, in which exogenous electron donors are needed. These donors may be reduced sulfur compounds such as hydrogen sulfide. This paper deals with the description of this metabolic process, representatives of the above-mentioned families, and discusses the possibility using anoxygenic phototrophic microorganisms for the detoxification of toxic hydrogen sulfide. Moreover, their general characteristics, morphology, metabolism, and taxonomy are described as Citation: Kushkevych, I.; Bosáková, well as the conditions for isolation and cultivation of these microorganisms will be presented. V.; Vítˇezová,M.; Rittmann, S.K.-M.R. -
Feeding-Dependent Tentacle Development in the Sea Anemone Nematostella Vectensis
bioRxiv preprint doi: https://doi.org/10.1101/2020.03.12.985168; this version posted March 12, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. Feeding-dependent tentacle development in the sea anemone Nematostella vectensis Aissam Ikmi1,2*, Petrus J. Steenbergen1, Marie Anzo1, Mason R. McMullen2,3, Anniek Stokkermans1, Lacey R. Ellington2, and Matthew C. Gibson2,4 Affiliations: 1Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany. 2Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA. 3Department of Pharmacy, The University of Kansas Health System, Kansas City, Kansas 66160, USA. 4Department of Anatomy and Cell Biology, The University of Kansas School of Medicine, Kansas City, Kansas 66160, USA. *Corresponding author. Email: [email protected] 1 bioRxiv preprint doi: https://doi.org/10.1101/2020.03.12.985168; this version posted March 12, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. Summary In cnidarians, axial patterning is not restricted to embryonic development but continues throughout a prolonged life history filled with unpredictable environmental changes. How this developmental capacity copes with fluctuations of food availability and whether it recapitulates embryonic mechanisms remain poorly understood. To address these questions, we utilize the tentacles of the sea anemone Nematostella vectensis as a novel paradigm for developmental patterning across distinct life history stages. -
Revised Glossary for AQA GCSE Biology Student Book
Biology Glossary amino acids small molecules from which proteins are A built abiotic factor physical or non-living conditions amylase a digestive enzyme (carbohydrase) that that affect the distribution of a population in an breaks down starch ecosystem, such as light, temperature, soil pH anaerobic respiration respiration without using absorption the process by which soluble products oxygen of digestion move into the blood from the small intestine antibacterial chemicals chemicals produced by plants as a defence mechanism; the amount abstinence method of contraception whereby the produced will increase if the plant is under attack couple refrains from intercourse, particularly when an egg might be in the oviduct antibiotic e.g. penicillin; medicines that work inside the body to kill bacterial pathogens accommodation ability of the eyes to change focus antibody protein normally present in the body acid rain rain water which is made more acidic by or produced in response to an antigen, which it pollutant gases neutralises, thus producing an immune response active site the place on an enzyme where the antimicrobial resistance (AMR) an increasing substrate molecule binds problem in the twenty-first century whereby active transport in active transport, cells use energy bacteria have evolved to develop resistance against to transport substances through cell membranes antibiotics due to their overuse against a concentration gradient antiretroviral drugs drugs used to treat HIV adaptation features that organisms have to help infections; they -
Limits of Life on Earth Some Archaea and Bacteria
Limits of life on Earth Thermophiles Temperatures up to ~55C are common, but T > 55C is Some archaea and bacteria (extremophiles) can live in associated usually with geothermal features (hot springs, environments that we would consider inhospitable to volcanic activity etc) life (heat, cold, acidity, high pressure etc) Thermophiles are organisms that can successfully live Distinguish between growth and survival: many organisms can survive intervals of harsh conditions but could not at high temperatures live permanently in such conditions (e.g. seeds, spores) Best studied extremophiles: may be relevant to the Interest: origin of life. Very hot environments tolerable for life do not seem to exist elsewhere in the Solar System • analogs for extraterrestrial environments • `extreme’ conditions may have been more common on the early Earth - origin of life? • some unusual environments (e.g. subterranean) are very widespread Extraterrestrial Life: Spring 2008 Extraterrestrial Life: Spring 2008 Grand Prismatic Spring, Yellowstone National Park Hydrothermal vents: high pressure in the deep ocean allows liquid water Colors on the edge of the at T >> 100C spring are caused by different colonies of thermophilic Vents emit superheated water (300C or cyanobacteria and algae more) that is rich in minerals Hottest water is lifeless, but `cooler’ ~50 species of such thermophiles - mostly archae with some margins support array of thermophiles: cyanobacteria and anaerobic photosynthetic bacteria oxidize sulphur, manganese, grow on methane + carbon monoxide etc… Sulfolobus: optimum T ~ 80C, minimum 60C, maximum 90C, also prefer a moderately acidic pH. Live by oxidizing sulfur Known examples can grow (i.e. multiply) at temperatures which is abundant near hot springs. -
THE CASE AGAINST Marine Mammals in Captivity Authors: Naomi A
s l a m m a y t T i M S N v I i A e G t A n i p E S r a A C a C E H n T M i THE CASE AGAINST Marine Mammals in Captivity The Humane Society of the United State s/ World Society for the Protection of Animals 2009 1 1 1 2 0 A M , n o t s o g B r o . 1 a 0 s 2 u - e a t i p s u S w , t e e r t S h t u o S 9 8 THE CASE AGAINST Marine Mammals in Captivity Authors: Naomi A. Rose, E.C.M. Parsons, and Richard Farinato, 4th edition Editors: Naomi A. Rose and Debra Firmani, 4th edition ©2009 The Humane Society of the United States and the World Society for the Protection of Animals. All rights reserved. ©2008 The HSUS. All rights reserved. Printed on recycled paper, acid free and elemental chlorine free, with soy-based ink. Cover: ©iStockphoto.com/Ying Ying Wong Overview n the debate over marine mammals in captivity, the of the natural environment. The truth is that marine mammals have evolved physically and behaviorally to survive these rigors. public display industry maintains that marine mammal For example, nearly every kind of marine mammal, from sea lion Iexhibits serve a valuable conservation function, people to dolphin, travels large distances daily in a search for food. In learn important information from seeing live animals, and captivity, natural feeding and foraging patterns are completely lost. -
Marine Microplankton Ecology Reading
Marine Microplankton Ecology Reading Microbes dominate our planet, especially the Earth’s oceans. The distinguishing feature of microorganisms is their small size, usually defined as less than 200 micrometers (µm); they are all invisible to the naked eye. As a group, sea microbes are extremely diverse, and extremely versatile with respect to their abilities to make and eat food. All marine microbes are too small to swim against the current and are therefore classified as plankton. First we will discuss several ways to classify marine microbes. 1. Size Planktonic marine organisms can be divided into the following size categories: Category Size femtoplankton <0.2 µm picoplankton 0.2-2 µm nanoplankton 2-20 µm microplankton 20-200 µm mesoplankton 200-2000 µm In this laboratory we are concerned with the microscopic portion of the plankton, less than 200 µm. These organisms are not visible to the naked eye (Figure 1). Figure 1. Size classes of marine plankton 2. Type A. Viruses Viruses are the smallest and simplest microplankton. They range from 0.01 to 0.3 um in diameter. Externally, viruses have a capsid, or protein coat. Viruses can also have simple or complex external morphologies with tail fibers and structures that are used to inject DNA or RNA into their host. Viruses have little internal morphology. They do not have a nucleus or organelles. They do not have chlorophyll. Inside a virus there is only nucleic acid, either DNA or RNA. Viruses do not grow and have no metabolism. Marine viruses are highly abundant. There are up to 10 billion in one liter of seawater! B. -
Human Microbiome: Your Body Is an Ecosystem
Human Microbiome: Your Body Is an Ecosystem This StepRead is based on an article provided by the American Museum of Natural History. What Is an Ecosystem? An ecosystem is a community of living things. The living things in an ecosystem interact with each other and with the non-living things around them. One example of an ecosystem is a forest. Every forest has a mix of living things, like plants and animals, and non-living things, like air, sunlight, rocks, and water. The mix of living and non-living things in each forest is unique. It is different from the mix of living and non-living things in any other ecosystem. You Are an Ecosystem The human body is also an ecosystem. There are trillions tiny organisms living in and on it. These organisms are known as microbes and include bacteria, viruses, and fungi. There are more of them living on just your skin right now than there are people on Earth. And there are a thousand times more than that in your gut! All the microbes in and on the human body form communities. The human body is an ecosystem. It is home to trillions of microbes. These communities are part of the ecosystem of the human Photo Credit: Gaby D’Alessandro/AMNH body. Together, all of these communities are known as the human microbiome. No two human microbiomes are the same. Because of this, you are a unique ecosystem. There is no other ecosystem like your body. Humans & Microbes Microbes have been around for more than 3.5 billion years. -
18.4 Bacteria and Archaea Kingdom Eubacteria Domain Bacteria
18.4 Bacteria and Archaea Kingdom Eubacteria Domain Bacteria 18.4 Bacteria and Archaea Description Bacteria are single-celled prokaryotes. 18.4 Bacteria and Archaea Where do they live? Prokaryotes are widespread on Earth. ( Est. over 1 billion types of bacteria, and over 1030 individual prokaryote cells on earth.) Found in all land and ocean environments, even inside other organisms! 18.4 Bacteria and Archaea Common Examples • E. Coli • Tetanus bacteria • Salmonella bacteria • Tuberculosis bacteria • Staphylococcus • Streptococcus 18.4 Bacteria and Archaea Modes Of Nutrition • Bacteria may be heterotrophs or autotrophs 18.4 Bacteria and Archaea Bacteria Reproduce How? • by binary fission. • exchange genes during conjugation= conjugation bridge increases diversity. • May survive by forming endospores = specialized cell with thick protective cell wall. TEM; magnification 6000x • Can survive for centuries until environment improves. Have been found in mummies! 18.4 Bacteria and Archaea • Bacteria Diagram – plasmid = small piece of genetic material, can replicate independently of the chromosome – flagellum = different than in eukaryotes, but for movement – pili = used to stick the bacteria to eachpili other or surfaces plasma membrance flagellum chromosome cell wall plasmid This diagram shows the typical structure of a prokaryote. Archaea and bacteria look very similar, although they have important molecular differences. 18.4 Bacteria and Archaea • Classified by: their need for oxygen, how they gram stain, and their shapes 18.4 Bacteria and Archaea Main Groups by Shapes – rod-shaped, called bacilli – spiral, called spirilla or spirochetes – spherical, called cocci Spirochaeta: spiral Lactobacilli: rod-shaped Enterococci: spherical 18.4 Bacteria and Archaea • Main Groups by their need for oxygen. -
Microbial Growth
7 Microbial Growth 1 7.1 Reproductive strategies 1. Describe binary fission as observed in bacteria and archaea 2. Compare the three reproductive strategies used by bacteria other than binary fission 2 Reproductive Strategies • The reproductive strategies of eukaryotic microbes – asexual and sexual, haploid or diploid • Bacteria and Archaea – haploid only, asexual - binary fission, budding, filamentous – all must replicate and segregate the genome prior to division 3 4 7.2 Bacterial cell cycle 1. Summarize the two major events in a typical bacterial cell cycle 2. State the functions of cytoskeletal proteins in a typical bacterial cell cycle and in determining cell shape 5 Bacterial Cell Cycle • Cell cycle is sequence of events from formation of new cell through the next cell division – most bacteria divide by binary fission • Two pathways function during cycle – DNA replication and partition – cytokinesis 6 Chromosome Replication and Partitioning - 1 • Most bacterial chromosomes are circular • Single origin of replication – site at which replication begins • Terminus – site at which replication is terminated, located opposite of the origin • Replisome – group of proteins needed for DNA synthesis • DNA replication proceeds in both directions from the origin • Origins move to opposite ends of the cell 7 8 Chromosome Partitioning • Replisome pushes, or condensation of, daughter chromosomes to opposite ends • MreB (murein cluster B) – an actin homolog, plays role in determination of cell shape as spiral inside cell periphery, and chromosome -
Chromochloris Zofingiensis (Chlorophyceae) Divides By
biology Article Chromochloris zofingiensis (Chlorophyceae) Divides by Consecutive Multiple Fission Cell-Cycle under Batch and Continuous Cultivation Idan Koren, Sammy Boussiba , Inna Khozin-Goldberg and Aliza Zarka * Microalgal Biotechnology Laboratory, French Associates Institute for Agriculture and Biotechnology of Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boker Campus, Midreshet Ben-Gurion 8499000, Israel; [email protected] (I.K.); [email protected] (S.B.); [email protected] (I.K.-G.) * Correspondence: [email protected] Simple Summary: Microalgae are plant-like micro-organisms naturally found in fresh and marine water environments, inhabiting a vast range of ecosystems. They capture light energy through photosynthesis and convert low energy inorganic compounds (carbon dioxide and water) into high energy complex organic compounds, such as carbohydrates and fats. Chromochloris zofingiensis is a unicellular microalga currently under intensive research, due to its ability to produce high value pharmaceutical and nutritional pigments. Understanding its growth characteristics is crucial for the establishment of an efficient commercial production of those pigments from this alga. Thus, we have developed a method to stain the nucleus of the alga which enabled us to follow the division pattern under commonly used cultivation methods. We found that C. zofingiensis cells conduct consecutive Citation: Koren, I.; Boussiba, S.; DNA synthesis and divisions of the nucleus to produce 8 or 16 nuclei before it divides into 8 or Khozin-Goldberg, I.; Zarka, A. 16 daughter cells, respectively. Under high light illumination, the whole process lasts several days, Chromochloris zofingiensis through which cells grow during the light period and divide during the dark period. -
The Unicellular and Colonial Organisms Prokaryotic And
The Unicellular and Colonial Organisms Prokaryotic and Eukaryotic Cells As you know, the building blocks of life are cells. Prokaryotic cells are those cells that do NOT have a nucleus. They mostly include bacteria and archaea. These cells do not have membrane-bound organelles. Eukaryotic cells are those that have a true nucleus. That would include plant, animal, algae, and fungal cells. As you can see, to the left, eukaryotic cells are typically larger than prokaryotic cells. Today in lab, we will look at examples of both prokaryotic and eukaryotic unicellular organisms that are commonly found in pond water. When examining pond water under a microscope… The unpigmented, moving microbes will usually be protozoans. Greenish or golden-brown organisms will typically be algae. Microorganisms that are blue-green will be cyanobacteria. As you can see below, living things are divided into 3 domains based upon shared characteristics. Domain Eukarya is further divided into 4 Kingdoms. Domain Kingdom Cell type Organization Nutrition Organisms Absorb, Unicellular-small; Prokaryotic Photsyn., Archaeacteria Archaea Archaebacteria Lacking peptidoglycan Chemosyn. Unicellular-small; Absorb, Bacteria, Prokaryotic Peptidoglycan in cell Photsyn., Bacteria Eubacteria Cyanobacteria wall Chemosyn. Ingestion, Eukaryotic Unicellular or colonial Protozoa, Algae Protista Photosynthesis Fungi, yeast, Fungi Eukaryotic Multicellular Absorption Eukarya molds Plantae Eukaryotic Multicellular Photosynthesis Plants Animalia Eukaryotic Multicellular Ingestion Animals Prokaryotic Organisms – the archaea, non-photosynthetic bacteria, and cyanobacteria Archaea - Microorganisms that resemble bacteria, but are different from them in certain aspects. Archaea cell walls do not include the macromolecule peptidoglycan, which is always found in the cell walls of bacteria. Archaea usually live in extreme, often very hot or salty environments, such as hot mineral springs or deep-sea hydrothermal vents.