Viruses & The Six Kingdoms

VIRUSES & THE 6 KINGDOMS Directions: When this symbol is present, notes should be taken.

Viruses Background Viruses are agents that can infect both animals and plants. Viruses called bacteriophages, can also attack bacteria. Viruses, however, are not cells. Viruses depend upon a host cell to survive Once inside a host cell, a virus goes into “living mode” showing two characteristics of life-(1)reproduction and (2)heredity with the ability to mutate.

Structure of Viruses Viruses contain genetic material, either DNA or RNA, enclosed in a protective coating of protein called a capsid. The capsid may be surrounded by a lipid envelope. This section of the virus containing the genetic material is referred to as the head. Some viruses also contain a tail and tail fibers that allow the virus to attach to its host.

Diagram of a Bacteriophage

Structure of Viruses (slide 2) Other viruses, such as the HIV virus (right), do not have tail fibers, but instead have glycoproteins inserted into their lipid envelope. These glycoproteins help the virus bind to its host cell.

Infection Pathways (2) Viruses cause infection by following one of two pathways: (1) lytic and/or (2) lysogenic. In the lytic pathway, the virus enters a host cell, replicates, and causes it to lyse, or burst, resulting in cell death. When following the lysogenic pathway, the virus enters the cell and becomes part of it. Cell death does not occur right away, rather the virus becomes latent, or inactive, remaining in the cell until something triggers it to become activated. When activated, the virus enters the lytic pathway

Viruses infect other cells!!! Lytic Pathway Viruses infect other cells!!! Virus contacts cell, and inserts DNA. 4. Viruses cause cell to lyse. 2. Viral DNA replicates. 3. Virus replicates.

Lysogenic Pathway LYTIC PATHWAY 4. Viral goes on Virus contacts cell, inserts DNA. 4. Viral goes on to enter the lytic pathway. 2. In lysogenic pathway, Viral DNA becomes integrated into host cell DNA 3. DNA, with integrated viral DNA, replicates and cell divides.

The Modern Day Classification System By Carolus Linnaeus Binomial Nomenclature -2 word naming system -1st word identifies the genus -2nd word identifies the species -Example: Homo sapien Eight Taxa Domain Kingdom Phylum or Division Class Order Family Genus Species 3 Domains Archae Bacteria Eukarya Six Kingdoms Archaebacteria Eubacteria Protists Fungi Plants Animals

Three Ways Kingdoms Were Determined Classifying Organisms Three Additional Aspects We Will Examine Three Ways Kingdoms Were Determined 1. Cell Type Eukaryotic (true nucleus & membrane-bound organelles) Prokaryotic (no nucleus) 2. Body Type (# of cells in body) Unicellular (one cell) Multi-cellular (two or more cells) 3. Means of Nutrition Autotrophs (make own food) Heterotrophs (feed on other organisms) 4. Cell Wall Components Chitin Cellulose 5. Characteristics Unique Traits Special Abilities 6. Examples Give scientific and/or common name Draw a picture (optional)

Archaebacteria Prokaryotic cells Unicellular Autotrophic & Heterotrophic Cell Wall-made of sugars & amino acids Formerly Kingdom Monera & Found in extreme environments Hot boiling water/Thermal vents Anaerobic conditions Highly acidic environments 6. Salt-loving (Halophiles), Methane-producing (Methanogens), Heat & Acid-Loving (Thermophiles)

Eubacteria Prokaryotic cells Unicellular Heterotrophs and Autotrophs Cell wall made of sugars & amino acids Formerly Kingdom Monera (Found Everywhere) Examples Three Types Streptococci Cocci E. coli Bacilli Samonella Spirilli

Protista Eukaryotic cells Most unicellular Most Heterotrophic Some have cell walls made up of cellulose or chitin Most diverse: Often referred to as a “junk drawer” because it contains microscopic organisms that are animal-like, plant-like, and fungus-like Examples (AL) Amoeba & Paramecium, (PL) Algae & Euglena, (FL) Slime Mold

Fungi Eukaryotic cells Most are multi-cellular Heterotrophs Cell walls made of chitin Earth’s Decomposers Examples Mushrooms Mold Mildew Yeast

Plantae Eukaryotic cells Multi-cellular Autotroph (Primary Producers) Cell walls made of cellulose Second largest kingdom with Over 250,000 species Examples Flowering plants, Trees Mosses, Ferns

Kingdom Plantae multicellular - possess chloroplasts and cell walls make their own food - PHOTOSYNTHESIS Reproduce sexually – can be asexual Vascular plants are more advanced - they have evolved specialized tissues, xylem, which is involved in structural support and water conduction, and phloem, which functions in food conduction Nonvascular plants are usually no more than an inch or two in height because they do not have adequate support, which is provided by vascular tissues to other plants, to grow bigger

ONION CELLS FROM LAB – NOTE THE BOXY SHAPE OF PLANT CELLS & THE DISTINCT CELL WALL

Animalia Eukaryotic cells Multi-cellular Heterotrophs (Motile, Complex) No Cell walls Largest kingdom with Over 1 million known species Examples: Sponges, Worms, Insects, Fish, Amphibians, Reptiles, Birds, Mammals

Kingdom Animalia multi-cellular organisms which ingest their food – HETEROTROPHS Reproduce sexually