1 / 34

The Single Cell:

The Single Cell:. Viruses, Bacteria, & Protists. What do you notice as the levels go from atom to organism?. Once at the organism level how do we organize?. Why are levels of organization important?. Structure:. Viruses, Bacteria, & Protists. DNA o r RNA. What is a Virus?.

Download Presentation

The Single Cell:

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.


Presentation Transcript

  1. The Single Cell: Viruses, Bacteria, & Protists

  2. What do you notice as the levels go from atom to organism? Once at the organism level how do we organize? Why are levels of organization important?

  3. Structure: Viruses, Bacteria, & Protists

  4. DNA or RNA What is aVirus? ½ to 1/100 the size of the smallest bacteria Classification on basis of nucleic acid • DNA viruses: - Herpes simplex virus (HSV) • RNA viruses: - influenza virus

  5. Structure of aVirus? • Envelope – additional layer surrounding the capsid Genetic material • Capsid - a shell of protein surrounding nucleic acid Capsid Envelope Lipid bilayer Proteins determine the viruses shape: Polyhedral - papilloma virus with projections - HIV helical - tobacco mosaic virus Polyhedral head w/cylindrical tail w/ leg fibers

  6. What are Bacteria? Kingdom Archebacteria Prokaryote Extreme environment No free O2 High salt or sulfur concentration Some produce methane The Extremists!

  7. What are Bacteria? Kingdom Eubacteria Human pathogens Decomposers Symbiotic living Prepare food Make antibiotics Can be found just about anywhere

  8. Structure of Bacteria Prokaryotic cells lack a nucleus and membrane bound organelles Common shapes among prokaryotes are spheres, rods, & spirals

  9. What are Protists? Kingdom Protista All organisms that are neither animals, plants, bacteria or fungi are called 'protists' Unicellular, multicellular, colonial Eukaryotic Aquatic environments

  10. What are Protists? Plant like Protists - Algae Live in fresh or salt water Reproduction & metabolism similar to plants Animal like Protists - Protozoa Aquatic All are single celled Metabolism similar to animals Grouped according to how they move Pseudopod Ciliate Sporazoan Flagellate Fungus like Protists – plasmodium, slime mold, downy mildew Behavior & metabolism similar to fungus

  11. Reproduction: Viruses, Bacteria, & Protists

  12. Viral Reproduction Lytic Cycle The viruses attaches to a host cell and deposits its DNA The viral DNA instructs the host cell to use its own enzyme raw material & energy to only make new viruses The new viruses burst from the host cell – killing it – & are able to go infect other cells • Attachment • Entry • Replication • Assembly • Release

  13. Viral Reproduction Lysogenic Cycle The viral DNA is integrated into the host cells chromosome - provirus Every time the host cell replicates it also replicates the viral DNA Once activated, the provirusenters the lytic cycle replicates and kills the host cell • Attachment • Entry • Provirus formation • Replication • Assembly • Release

  14. Bacterial Reproduction Most prokaryotes have a single, circular, double-stranded DNA chromosome condensed in the nucleoid region of the cytoplasm Many bacteria have an additional small ring of DNA – The Plasmid – prokaryotes can survive without the plasmid the genes for essential functions are on the chromosome. Plasmids sometimes contain genes for resistance and other special issues

  15. Bacterial ReproductionASEXUAL No cell cycle like seen in Eukaryotes Prokaryotes reproduce mostly asexually via binary fission, making DNA almost continuously • No mitosis or meiosis • Translation and transcription • occur simultaneously • Allows for rapid response to Environment – ADAPTATION

  16. Bacterial ReproductionSEXUAL • Conjugation, one cell directly transfers DNA to another • Resulting in a bacterium with a new genetic composition

  17. Plant Like Protist Reproduction Asexual & Sexual (haploid) (haploid) (haploid) (diploid) (diploid) (diploid) Fragmentationoccurs when a filament breaks apart and each piece develops into another organism. Spirogyra Conjugation occurs when two filaments form conjugation tubes. The contents of one cell passes through the tube an fuses with a cell from the other filament. Fertilization occurs and a zygote is formed. Alternation of generations Sexual and asexual reproduction occurs during alternating periods in the life cycle of the plant like protist.

  18. Animal Like Protist Reproduction Multiply asexually by fission. The cell divides into two individuals. Paramecium undergoing fission. Fungus Like Protist Reproduction Plasmodium - Reproduces by haploid spores Slim molds are haploid their entire life & reproduce by cell division

  19. Metabolism: Viruses, Bacteria, & Protists

  20. Do viruses need energy? Do viruses need to “eat”? Do viruses produce waste? Do viruses have a metabolism? HOST CELL DOES IT ALL!

  21. HeterotrophicBacteria Use organic molecules as a food source Parasites – Unable to produce organic molecules Obtain nutrients from living organisms Excretes waste thru cell wall Saprophytes– Feed on dead organisms or organic waste Break down nutrients locked in body tissues of dead organisms Excretes waste thru cell wall

  22. Photosynthetic autotrophs – Contain chlorophyll Excretes waste thru cell wall Autotrophic Bacteria Use sunlight to make organic molecules Make organic molecules from inorganic ones Chemosynthetic autotrophs – Obtain energy needed to make food from Chemicals like sulfur & nitrogen Excretes waste thru cell wall NITROGEN FIXATION

  23. Protists Animal like Heterotrophic – feed on other organisms or dead organic matter. Some are parasitic Have specialized organelles used to release waste Plant like Able to perform photosynthesis contain chlorophyll Not all are green. Diatoms & dinoflagellates have yellow to brown chloroplasts. There are brown algae & red algae Release waste thru cell wall Fungus like Heterotrophic Plasmodium Eats as it moves MildewFeed on dead organisms Releases waste thru cell membrane

  24. Gas Exchange: Viruses, Bacteria, & Protists

  25. Why is gas exchange important? Do viruses need oxygen or carbon dioxide? HOST CELL DOES IT ALL!

  26. Bacteria Metabolism Obligate aerobes – require oxygen Mycobacterium tuberculosis – the organism that causes the lung disease tuberculosis Obligate anaerobes – require NO oxygen Treponemapallidum – the bacterium that causes syphilis

  27. Bacteria Metabolism Prokaryotes used infolded regions of the plasma membrane to perform many metabolic functions, including cellular respiration and photosynthesis. Respiratory membranes in aerobes Thykaloid membranes in photosynthetic bacteria Autotroph Heterotroph

  28. Protists Metabolism Protists are eukaryotic cells Have many specialized organelles including mitochondria or chloroplasts used in cellular respiration Protists are aerobic – they require oxygen Paramecium

  29. Homeostasis: Viruses, Bacteria, & Protists

  30. What is HOMEOSTASIS? Why is it important? How do VIRUSES maintain homeostasis? They DON’T! The Host Cell does it for them!!

  31. Bacteria Homeostasis The cell wall maintains the shape of the cell, protects the cell, and prevents the cell from bursting in a hypotonic environment When life gets rough some bacteria can form resistant endospores Endospores contain a bacterium’s DNA and a small amount of cytoplasm Endospores are encased in a tough outer covering that resists drying out and extreme temperatures

  32. Protist Homeostasis Because the kingdom protista contains such a variety, several homeostatic behaviors exist If you would keep Euglenoids in the dark they start feeding on organic matter and may loose their chloroplast. Sometimes classified as animal like other times classified as plantlike Amoebas can grow to very large sizes. Some species are 5 mm long! They can survive by having many nuclei within their single cell. Star-shaped contractile vacuoles are used to balance the amount of water in the cell. Two nuclei contain the genetic information.

  33. Are viruses alive? What are the characteristics of life? Reproduction Genetic information Maintain Homeostasis How do characteristics of viruses compare to that of living organisms? Metabolism Cellular organization

  34. Are viruses alive? NO How do characteristics of viruses compare to that of living organisms? No cell organization Has genetic material Unable to reproduce with out a host cell Use host cell’s metabolism Homeostasis?

More Related