Questions and Answers
What distinguishes motile bacteria from non-motile bacteria?
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How does binary fission occur in bacteria?
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Describe the process of transformation in bacteria.
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What are the distinguishing features of viruses compared to bacteria?
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What is a bacteriophage and what is its significance?
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What is the main difference between yeasts and molds in terms of structure?
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List two types of viral genetic material.
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Describe the process of plasmogamy in fungal sexual reproduction.
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What happens during the attachment phase of the lytic cycle?
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What type of reproduction do fungi exhibit when they form new individuals from sporangiospores?
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Identify the structure that encases viral genetic material.
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What are the reproductive units of fungi called?
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How do protozoans obtain nutrients?
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What distinguishing feature do ciliated protozoans possess?
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What triggers dimorphism in certain fungi?
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What is the role of karyogamy in fungal reproduction?
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What shapes can bacteria exhibit and how does this aid in their identification?
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What is the main component of the bacterial cell wall and its function?
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Describe the significance of Alexander Fleming's discovery in 1928.
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Contrast the characteristics of gram-positive and gram-negative bacteria.
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What role did the mass production of penicillin play during World War II?
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How do the morphological characteristics of bacteria assist in identifying pathogenic microorganisms?
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What distinguishes prokaryotic organisms like bacteria from eukaryotic cells?
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What was Jenner's contribution to vaccination, and why is it important?
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Study Notes
Bacteria
- Unicellular, prokaryotic microorganisms with no true nucleus or membrane-bound organelles.
- Found in diverse environments, including extreme conditions like hot springs and deep-sea vents.
Motility
- Some bacteria, like Salmonella, are motile and possess flagella; others are non-motile.
Classification
- Domain: Bacteria
- Kingdom: Monera (or Bacteria)
Examples
- Escherichia coli (E. coli) – Gram-negative rod.
- Staphylococcus aureus – Gram-positive cocci.
- Mycobacterium tuberculosis – Acid-fast bacterium causing tuberculosis.
Reproduction
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Asexual:
- Binary Fission: Primary reproduction method, where one cell divides into two identical cells.
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Horizontal Gene Transfer:
- Conjugation: Genetic material transfer through direct contact.
- Transformation: Uptake of free DNA from the environment.
- Transduction: DNA transfer between bacteria via bacteriophages.
Viruses
- Non-cellular, obligate intracellular parasites made of genetic material (DNA or RNA) enclosed in a protein coat (capsid).
- Can only replicate within a host cell.
Morphological Characteristics
- Size: Typically 20 to 300 nanometers, smaller than bacteria.
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Shape:
- Icosahedral: Symmetrical, spherical (e.g., Adenovirus).
- Helical: Rod-like (e.g., Tobacco mosaic virus).
- Complex: Combination of shapes (e.g., Bacteriophage).
Components
- Capsid: Protein coat composed of capsomeres.
- Envelope: Some have an outer lipid membrane (e.g., Influenza virus).
- Genetic Material: DNA or RNA, can be single-stranded or double-stranded, linear or circular.
Classification
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By Genetic Material:
- DNA Viruses: e.g., Adenovirus.
- RNA Viruses: e.g., Influenza virus, HIV.
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By Host Range:
- Bacteriophages: Infect bacteria (e.g., T4 bacteriophage).
- Animal Viruses: Infect animal cells (e.g., Rabies virus).
- Plant Viruses: Infect plant cells (e.g., Tobacco mosaic virus).
Reproduction
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Lytic Cycle:
- Attachment: Virus binds to host cell.
- Penetration: Viral genetic material enters host cell.
- Biosynthesis: Host cell synthesizes viral components.
- Assembly: Formation of new viral particles.
- Release: Host cell bursts, releasing new viruses.
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Lysogenic Cycle: Viral DNA integrates into host genome, replicates without harming the host.
Fungi
- Eukaryotic organisms that can be unicellular (yeasts) or multicellular (molds, mushrooms).
- Non-photosynthetic; obtain nutrients through absorption.
Morphological Characteristics
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Structure:
- Yeasts: Unicellular, often oval or spherical (e.g., Saccharomyces cerevisiae).
- Molds: Multicellular with filamentous hyphae forming mycelium (e.g., Aspergillus).
- Mushrooms: Fruiting bodies with a cap and stalk (e.g., Agaricus).
- Cell Wall: Composed of chitin and glucans.
- Spores: Reproductive units, can be asexual or sexual.
- Dimorphism: Some fungi switch forms based on environmental conditions (e.g., Histoplasma capsulatum).
Classification
- Kingdom: Fungi
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Phyla:
- Ascomycota: Sac fungi (e.g., Penicillium).
- Basidiomycota: Club fungi (e.g., Agaricus).
- Zygomycota: Conjugation fungi (e.g., Rhizopus).
- Chytridiomycota: Aquatic fungi (e.g., Batrachochytrium).
Reproduction
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Asexual:
- Budding: Seen in yeasts (e.g., Saccharomyces cerevisiae).
- Fragmentation: Hyphae break into pieces, each capable of forming a new fungus.
- Spore Formation: Conidia or sporangiospores formed via mitosis.
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Sexual:
- Plasmogamy: Fusion of two hyphae.
- Karyogamy: Fusion of nuclei.
- Meiosis: Produces sexual spores (e.g., ascospores, basidiospores).
Protozoans
- Unicellular, eukaryotic microorganisms that can be free-living or parasitic.
- Heterotrophic with diverse morphologies.
Morphological Characteristics
- Shapes include:
- Amoeboid: Irregular shape using pseudopodia (e.g., Amoeba).
- Ciliated: Covered with cilia for movement (e.g., Paramecium).
Historical Milestones in Immunology
- 1798: Edward Jenner published findings on vaccination, promoting smallpox vaccine use globally.
- 1928: Alexander Fleming discovered penicillin, the first true antibiotic from Penicillium notatum.
- 1940s: Mass production of penicillin began, revolutionizing bacterial infection treatments.
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Description
Test your knowledge on the classification, motility, and reproduction of bacteria. This quiz covers important examples such as E. coli and Staphylococcus aureus, along with their characteristics and modes of reproduction. Dive into the fascinating world of microbiology and see how much you know!
