Test #2 Review Flashcards

Ch. 4, 5, & 6 Review

Ch. 4: Habitats, Communities, and Microbiomes

• Habitats and Communities: General understanding.
• Microbiomes:
  • Definition: Microbial communities inhabiting a particular environment.
  • Importance: Crucial roles in host health, nutrient cycling, and environmental processes.
• Types of Symbioses:
  • Mutualism: Both organisms benefit (e.g., bacteria in the human gut).
  • Commensalism: One organism benefits, and the other is unaffected (e.g., skin bacteria).
  • Parasitism: One organism benefits at the expense of the other (e.g., pathogens).
  • Examples for each type should be known.
• Taxonomy:
  • Gram-positive vs. Gram-negative bacteria.
  • Atypical bacteria (e.g., lacking a cell wall).

Ch. 4: Bacterial Taxonomy and Metabolism

• For each taxonomic group, understand metabolism, clinical relevance, and unique characteristics.
• Gram-Negative Proteobacteria:
  • Alphaproteobacteria: Examples and key features.
  • Betaproteobacteria: Examples and key features.
  • Gammaproteobacteria: Examples and key features.
  • Deltaproteobacteria: Examples and key features.
  • Epsilonproteobacteria: Examples and key features.
• Gram-Negative Nonproteobacteria:
  • Spirochetes: Examples (e.g., Treponema, Borrelia) and key features (e.g., axial filaments).
  • Planctomycetes: Examples and unique characteristics (e.g., compartmentalized cells).
  • CFB Group (Cytophaga, Flavobacterium, Bacteroides): Examples and key features.
• Phototrophic Bacteria:
  • Green vs. Purple Bacteria: Distinguishing characteristics.
  • Sulfur vs. Nonsulfur Bacteria: Distinguishing characteristics in metabolism.
  • Cyanobacteria: Oxygenic photosynthesis and ecological importance.
• Gram-Positive Bacteria:
  • High vs. Low G+C Content: Two main groups.
  • Firmicutes: Examples (e.g., Bacillus, Clostridium, Staphylococcus, Streptococcus) and key features.
  • Actinobacteria: Examples (e.g., Mycobacterium, Streptomyces) and key features.
  • Tenericutes: Mycoplasmas (lack cell wall).
• Deeply Branching Bacteria:
  • Examples and significance in bacterial evolution.
• Archaea:
  • General characteristics and differences from Bacteria and Eukarya.

Ch. 5: Protozoa

• Life Stages:
  • Trophozoites: Active, feeding stage.
  • Cysts: Dormant, resistant stage.
• Reproduction:
  • Asexual:
    • Budding
    • Fission
    • Schizogony (multiple fission)
  • Sexual:
    • Syngamy (fusion of gametes)
    • Conjugation (transfer of genetic material)
• Cell Structures:
  • Plasmalemma: Cell membrane.
  • Pellicle: Flexible outer covering.
  • Ectoplasm: Outer layer of cytoplasm.
  • Endoplasm: Inner layer of cytoplasm.
• Feeding Structures:
  • Cytostome: Cell mouth.
    • Holozoic (ingesting whole particles)
    • Saprozoic (ingesting dissolved nutrients)
  • Cytoproct: Cell anus.
• Locomotion Structures:
  • Flagella
  • Cilia
  • Pseudopodia (false feet)
• Unique Organelles:
  • Contractile Vacuoles: Osmoregulation.
  • Kinetoplast: DNA containing structure in some flagellates.
  • Hydrogenosomes: Produce hydrogen in some anaerobic protozoa.

Ch. 5: Protozoa, Algae, Helminths, Fungi, and Lichens

• Know metabolism, clinical relevance, distinguishing features, and general life cycles for each group.
• Protozoa:
  • Amoebozoa: Examples (e.g., Entamoeba) and key features (e.g., pseudopodia).
  • Excavata: Examples (e.g., Giardia, Trichomonas) and key features (e.g., flagella, undulating membrane).
  • Chromalveolata: Examples (e.g., Plasmodium, Paramecium) and key features (e.g., alveoli).
• Algae:
  • Chromalveolata: Examples (e.g., diatoms, dinoflagellates) and key features (e.g., pigments, cell walls).
  • Archaeplastida: Examples (e.g., green algae, red algae) and key features (e.g., chloroplasts).
• Helminths:
  • Nematoda (Roundworms): Examples (e.g., Ascaris, Enterobius) and key features (e.g., cylindrical body, complete digestive system).
  • Platyhelminths (Flatworms):
    • Trematodes (Flukes): Examples (e.g., Schistosoma) and key features (e.g., leaf-shaped, suckers).
    • Cestodes (Tapeworms): Examples (e.g., Taenia) and key features (e.g., segmented body, scolex).
• Fungi:
  • Mold vs. Yeast: Distinguishing characteristics.
  • Ascomycota: Examples (e.g., Saccharomyces, Aspergillus) and key features (e.g., ascospores).
  • Basidiomycota: Examples (e.g., mushrooms, Cryptococcus) and key features (e.g., basidiospores).
  • Microsporidia: Examples and unique characteristics (e.g., obligate intracellular parasites).
  • Zygomycota: Examples (e.g., Rhizopus) and key features (e.g., zygospores).
• Lichens:
  • Symbiotic association between fungi and algae or cyanobacteria.

Ch. 6: General Characteristics of Viruses

• Viruses: Acellular infectious agents.
• Bacteriophage: Viruses that infect bacteria.
• Types of Transmission:
  • Direct Contact: Physical contact.
  • Fomite: Inanimate object.
  • Mechanical Vector: Passive carrier.
  • Biological Vector: Active carrier; virus replicates in vector.
• General Virus Sizes: Typically measured in nanometers (nm).
• Components of Viruses:
  • Capsid: Protein coat.
  • Genetic Material: DNA or RNA (single-stranded or double-stranded).
  • Envelope: Lipid bilayer (present in some viruses).
  • Spikes: Glycoprotein projections (present in some viruses).
• Classification of Components/Structures: Based on morphology, genetic material, etc.
• Taxonomy and Classification of Viral Diseases: Based on symptoms, affected organs, etc.
• ICD Codes: Used for classifying diseases, including viral infections.

Ch. 6: Phage and Eukaryotic Viral Life Cycles

• Phage Life Cycle:
  • Virulent Phage (Lytic Cycle):
    • Stages: Attachment, entry, replication, assembly, release.
    • Generalized Transduction: Transfer of random bacterial DNA fragments.
  • Temperate Phage (Lysogenic Cycle):
    • Stages: Integration of viral DNA into host chromosome (prophage).
    • Specialized Transduction: Transfer of specific bacterial genes.
• Viral Life Cycle of Eukaryotes:
  • Differences from prokaryotes: Entry mechanisms, replication sites, etc.
• Nucleic Acid Biosynthesis:
  • ssDNA: Single-stranded DNA.
  • dsDNA: Double-stranded DNA.
  • (+)ssRNA: Positive-sense single-stranded RNA (can be directly translated).
  • (-)ssRNA: Negative-sense single-stranded RNA (requires conversion to (+)ssRNA).
  • dsRNA: Double-stranded RNA.
• RdRP (RNA-dependent RNA Polymerase): Enzyme that replicates RNA from an RNA template.
• Retrovirus:
  • Reverse Transcriptase: Enzyme that converts RNA to DNA.
  • Examples: HIV.
• Persistent Infections:
  • Latent: Virus remains dormant; no symptoms (e.g., herpesviruses).
  • Chronic: Virus replicates continuously; symptoms may persist (e.g., hepatitis B).
• Viral Life Cycles of Plants:
  • Common Characteristics: Transmission via vectors, mechanical damage.

Ch. 6: Viroids, Virusoids, Prions, and Virus Isolation/Cultivation

• Viroids:
  • Unique characteristics: Small, circular RNA molecules that infect plants.
  • Differences from viruses: Lack a capsid.
  • Examples.
• Virusoids:
  • Unique characteristics: ssRNA, Requires a helper virus for replication.
  • Differences from viruses: Encodes no proteins.
  • Examples.
• Prions:
  • Unique characteristics: Infectious proteins that cause misfolding of normal proteins.
  • Differences from viruses: Lack nucleic acid.
  • Examples: Creutzfeldt-Jakob disease (CJD), mad cow disease.
• Isolation of Viruses:
  • 1890s Ivanovski: Demonstration that viruses could pass through porcelain filters.
  • Porcelain Filter: Used to separate bacteria from viruses.
  • TMD (Transmembrane Domain).
• Cultivating Viruses:
  • In vivo: In living organisms (e.g., animals, eggs).
  • In vitro: In cell culture.
• Viral Growth Curve (Bacteriophage):
  • Stages: Latent period, rise period, decline period.
• Importance of Animal Virus Cultures:
  • Identification of viruses.
  • Vaccine production.
  • Virology research studies.
• Production of Influenza Vaccine:
  • Grown in embryonated chicken eggs.
• Tissue Growth and HeLa Cells:
  • HeLa cells: Immortal human cell line used in research.

Ch. 6: Detection of Viruses

• Effects on Cells:
  • Cytopathic effects (CPE): Visible changes in infected cells.
• Hemagglutination Assay:
  • Viruses agglutinate red blood cells.
• Nucleic Acid Amplification Tests (NAATs):
  • PCR (Polymerase Chain Reaction): Amplifies viral DNA or RNA.
• Enzyme Immunoassay (EIA):
  • Detects viral antigens or antibodies.