Microbiology Lesson Slides - Viruses, Bacteria, Protists, Fungi - PDF

MICROBIOLOGY Unit 2 Lesson 6 Microbiology Microbiology The study of microorganisms (microscopic organisms) Microbiology There are 4 types of microorganisms: 1) Viruses 2) Bacteria 3) Protists 4) Fungi Microbiology There are 4 types of microorganisms: 1) Viruses 2) Bacteria 3) Pro...

MICROBIOLOGY Unit 2 Lesson 6 Microbiology Microbiology The study of microorganisms (microscopic organisms) Microbiology There are 4 types of microorganisms: 1) Viruses 2) Bacteria 3) Protists 4) Fungi Microbiology There are 4 types of microorganisms: 1) Viruses 2) Bacteria 3) Protists 4) Fungi Viruses Viruses Latin for “poison” Lifeless particle that carries out no metabolic functions on its own Cannot reproduce on its own Once it invades a living cell it can reproduce Virus Size Virus Size Measured in units called nanometres (nm). (one nm equals one-billionth of a metre) Kilometer Meter Centimeter Millimeter Micrometer Nanometer Virus Size Virus Size Viruses range in size from 20 nm to 400 nm More than 5000 influenza viruses fit on head of a pin Virus Anatomy Virus Anatomy Consists of an inner nucleic acid strand (DNA or RNA) Surrounded by an outer protective protein coat called a capsid Capsid accounts for 95% of total virus Viruses and Human Health Viruses attack normal cells Destruction of these cells causes “symptoms” Viral infections are difficult to treat Not destroyed by antibiotics Viruses & Vaccines Vaccines Liquid preparations of dead or weakened viral cells, toxins, or RNA Stimulate immune system to fight back Some diseases can be prevented – Ex: polio, smallpox, hepatitis B Viruses DNA Viruses RNA Viruses Causes: Causes: Smallpox Measles Chickenpox Mumps Common Cold Influenza (Flu) HIV/AIDS Polio Hepatitis (Fecal contamination)  Viruses: Host Range Rabies Virus Host Range The variety of cells that a virus can enter Specific viruses can only enter specific cells Broad Host Range: Virus can infect a wide range of cells/species Common Cold Virus – Ex: Rabies Virus Can infect mammals, birds and reptiles Narrow Host Range: Virus can only enter specific cells – Ex: Common cold virus Can only enter cells of the upper respiratory tract Microbiology There are 4 types of microorganisms: 1) Viruses 2) Bacteria 3) Protists 4) Fungi Bacteria General Characteristics: All are unicellular; some stick together in colonies Lack nuclei, vacuoles, mitochondria and chloroplasts Single chromosome in the form of a DNA loop Have a rigid outer wall Reproduce asexually (without sex) Thrive in moist environments, become inactive if environment dries up Range in size from 0.4 micrometers to several micrometers (μm)  Non Viruses Living Eubacteria Prokaryotic Archaebacte Bacterial Cells ria No nucleus Living Cells Fungi Eukaryotic Plant & Animal Cells Protists True Nucleus  Non Viruses Living Eubacteria Prokaryotic Archaebacte ria Living Cells Fungi Eukaryotic Protists  Prokaryotic Cells Prokaryotic Cells Single celled Do not contain a nucleus Genetic material floats freely inside the cell in the nucleoid region Plasmid: small, DNA molecule that can replicate independently – Bacterial cells can exchange plasmids to gain information – Ex: Antibiotic resistance Bacteria: 2 Groups Prokaryotic cells can be divided into 2 groups: 1) Archaebacteria 2) Eubacteria  Bacteria: Archaebacteria I. Archaebacteria Thrive under extreme conditions a. Without oxygen b. Extremely hot environments c. Extremely saline environments Ex: intestines of mammals, volcanic deep-sea vents, salt Volcanic deep-sea vent Salt flats in Death flats (No light or oxygen, Valley, Nevada hot) (saline)  Bacteria: Eubacteria II. Eubacteria Eubacteria contain peptidoglycan in the cell walls When stained with a purple dye and a red dye we can see two types: 1. Gram-negative – Have less peptidoglycan and an extra outer layer – do not retain purple dye- so appear pinkish-red 2. Gram-positive – have more peptidoglycan- retain purple dye- so appear purple Bacteria: Eubacteria Shapes Eubacteria may be shaped as: Spheres Rods Curves or spirals  Spherical Rod Spiral Shape Eubacteri a Respiration Nutrition Anaerobic Autotrophs Heterotrophs Aerobic Either Photosynthetic Chemosynthetic Bacteria: Nutrition Nutrition of Eubacteria 1) Autotrophs Make food from inorganic substances 2) Heterotrophs Obtain their nutrients from other organisms Most bacteria are in this category  Bacteria: Nutrition Types of Autotrophs 1) Photosynthetic Convert carbon dioxide and water into carbohydrates by using energy from sunlight 2) Chemosynthetic Use chemical reactions as their energy source Microbiology There are 4 types of microorganisms: 1) Viruses 2) Bacteria 3) Protists 4) Fungi Protists Protists are extremely diverse – Shape – Size – Structure – Complexity – Feeding habits – Locomotion – Reproduction – Habitat Protists: Shared Characteristics Even with such diversity, protists share the following features: Most are unicellular Cells are eukaryotic (membrane-bound nucleus) Most reproduce asexually Cells thrive in moist surroundings (e.g. fresh water, salt water, animal fluids, very damp terrestrial environments) Protists Types There are 3 distinct group of protists: 1) Plant-like protists 2) Animal-like protists 3) Fungi-like protists Protists Types There are 3 distinct group of protists: 1) Plant-like protists 2) Animal-like protists 3) Fungi-like protists Protist Types: Plant-Like Protists Plant- Like Protists Plantlike because the organisms contain chlorophyll Energy is obtained through photosynthesis 2 groups of plant-like protists: 1) Euglena 2) Algae Plant-Like Protists: Euglena I. Euglena Euglena is a typical plantlike protist Two features of Euglena are the eyespot and the flagellum Eyespot: Believed to be how the organism detects light Flagellum: Used to propel the organism through water in a whip-like fashion Plant-Like Protists: Algae II. Algae Green, brown, and red algae (singular: alga) Normally considered to be aquatic Can also be found in soils, on lower trunks of trees, on rocks. Both brown and red algae are seaweeds Protists Types There are 3 distinct group of protists: 1) Plant-like protists 2) Animal-like protists 3) Fungi-like protists  Protist Types: Animal-Like Protists Animal-Like Protists Also called Protozoa All protozoa are heterotrophs Classified by their type of locomotion Four Types: 1) Pseudopod protozoans 2) Ciliated protozoans 3) Flagellated protozoans 4) Parasitic protozoans Animal-Like Protist Types: Pseudopod I. Pseudopod Protozoans Ex: Amoeba Large but simple Moves by repeatedly extending and retracting its pseudopods Feeds by phagocytosis Animal-Like Protist Types: Ciliated II. Ciliated Protozoans Ex: Paramecium Use hairlike structures for mobility Most advanced type Animal-Like Protist Types: Flagellated III. Flagellated Protozoans Ex: vorticella Moves by whipping their flagellum Flagellum Animal-Like Protist Types: Parasitic Parasitic Protozoa Depend entirely on body fluids of their hosts for movement Cannot live in an open environment on their own Protists Types There are 3 distinct group of protists: 1) Plant-like protists 2) Animal-like protists 3) Fungi-like protists Protist Types: Fungi-Like Protists Fungi-Like Protists Also called slime moulds Organisms prefer cool, shady, moist places Usually found under fallen leaves or on rotting logs Name comes from slimy trail left behind as mould travels over the ground At times, slime moulds resemble protozoans and become amoeba- like or have flagella At other times, they produce spores much as fungi do Microbiology There are 4 types of microorganisms: 1) Viruses 2) Bacteria 3) Protists 4) Fungi  Fungi Fungi Once classified as plants But they do not photosynthesize (many other differences) Usually the only visible parts of a fungus are the reproductive structures Plants vs Fungi Plants Fungi  Have one nucleus per  Often have many nuclei cell per cell  Most are autotrophs  Are heterotrophs  Starch is main storage  Have few or no storage molecule molecules  Most have roots  Have no roots  Have cellulose in cell  Often have chitin in cell walls walls  Some reproduce by  None reproduce by seed Fungi Fungi have mycelium Mesh of tiny branching filaments (hyphae) Exist where organism is attached to the substrate Provides transportation to pass nutrients to the fungal body Hyphae  Fungi: Hyphae Hyphae There are three possible hyphae appearances: 1. With cross-walls separating nuclei 2. Without cross-walls to separate nuclei 3. Mycelium showing many interlocking hypha Types of Fungi Types of Fungi Common Moulds Yeast, morels, truffles Mushrooms, shelf fungi Parasitic fungi REPRODUCTION IN MICROORGANIS MS  Virus Reproduction Viruses reproduce by Replication Virus, genetic material are duplicated in five steps 1) Attachment 2) Penetration 3) Synthesis of protein and nucleic acids 4) Assembly of the units 5) Release of new virus particles Virus Replication Steps 1 & 2 Attachment and Penetration Virus chemically recognizes a host cell Attaches to it and enters it Either whole virus or only its genetic material enters the cell’s cytoplasm Virus Replication Steps 3) Synthesis of Protein and Nucleic acids Information in viral DNA or RNA directs host cell in replicating viral components Ex: nucleic acids, enzymes, capsid proteins, and other viral proteins Virus Replication Steps 4) Assembly of the Units viral nucleic acids, enzymes, and proteins are brought together assembled into new virus particles Virus Replication Steps 5) Release of New Virus Particles Newly formed virus particles are released from infected cell Host cell dies (lysis) Entire process known as the “lytic cycle” Can be completed in as little as 25 to 45 min Bacterial Reproduction Bacteria can reproduce in 2 ways: 1) Asexually by binary fission 2) Sexually by conjugation Bacterial Reproduction: Binary Fission Binary Fission (Asexual) Bears some resemblance to mitosis but much simpler Single strand of DNA replicates so identical genetic material is transferred Crosswall is produced, dividing the cell into two identical bacteria May separate or remain attached Bacterial Reproduction: Conjugation Conjugation (Sexual) Not common but does occur in some such as E. coli and Salmonella Donor and recipient bacteria make cell-to-cell contact Across a special structure called a sex pilus Genetic material is swapped Giving each recipient an altered set of characteristics Then the two bacteria separate Protist Reproduction Protists reproduce three possible ways: 1) Some reproduce asexually by binary fission (amoebae) 2) Some reproduce asexually by longitudinal fission (Euglena) – After nuclear division, rest of the cell divides lengthwise 3) Only rarely do some reproduce sexually by conjugation  Fungal Reproduction Fungi Reproduce both asexually and sexually have a life cycle - Life cycle: development of an organism from a single cell to its reproductive stage Cycle is complete when the organism produces the next generation There is a wide variety of fungal life cycles Always produce spores (reproductive cells) Spores are produced in specialized reproductive structures called sporangia Spores are usually dispersed by air currents When in a suitable environment  sprout or germinate