BIO 214 General Microbiology Study Guide PDF

Study Guide for BIO 214: General Microbiology – Unit 4 Ch. 13 – Viruses, Viroids, and Prions 1. Viruses and Life: ○ Viruses are not alive because they lack cellular structure, metabolism, and cannot reproduce independently; they rely on host cells. ○ Discovery of v...

Study Guide for BIO 214: General Microbiology – Unit 4 Ch. 13 – Viruses, Viroids, and Prions 1. Viruses and Life: ○ Viruses are not alive because they lack cellular structure, metabolism, and cannot reproduce independently; they rely on host cells. ○ Discovery of viruses: Initially identified as infectious agents smaller than bacteria (e.g., tobacco mosaic virus). 2. Virus Characteristics: ○ Host range/tropism: Refers to the specific organisms, tissues, or cells a virus can infect. ○ Viruses vary in size (20-300 nm) and shape (helical, polyhedral, complex). ○ Virion: Complete virus particle. ○ Capsid: Protein coat around the viral genome. ○ Envelope: Lipid bilayer derived from host cell membranes. ○ Viral genomes vary in structure (DNA or RNA, single or double-stranded). 3. Viral Life Cycles: ○ Lytic cycle: Adsorption, penetration, biosynthesis, assembly, and release. ○ Lysogenic cycle: Integration of viral DNA into host genome (prophage), replication with host cell, and potential induction into the lytic cycle. ○ Life cycle of animal viruses: Adsorption, penetration, uncoating, replication, assembly, release. 4. Virus Culturing: ○ Tissue cultures: Cells grown in vitro to support viral replication. 5. Baltimore Classification: ○ Groups viruses based on genome type (DNA or RNA) and replication strategy. 6. Prions: ○ Infectious proteins (PrPSc) that convert normal cellular prion proteins (PrPC) into the infectious form, leading to neurodegenerative diseases. Ch. 14 – Principles of Disease and Epidemiology 1. Disease Basics: ○ Pathogen: Disease-causing agent. ○ Infection: Colonization by a microbe. ○ Disease: Resulting damage to host tissues. 2. Microbiota: ○ Acquired during birth and early life; composition influenced by diet, environment, and health.  ○ Roles: Compete with pathogens, synthesize vitamins, train the immune system. ○ Opportunistic pathogens: Normal microbiota that cause disease under certain conditions. 3. Epidemiology Concepts: ○ Prevalence: Total cases in a population. ○ Incidence: New cases in a time period. ○ Disease distribution: Endemic (constant presence), epidemic (localized outbreak), pandemic (global outbreak). ○ John Snow: Father of modern epidemiology; traced cholera to contaminated water. 4. Transmission and Control: ○ Disease reservoirs: Human, animal, and environmental sources. ○ Transmission: Direct, indirect, droplet, vector-borne. ○ Emerging diseases: Result from environmental changes, human behavior, or microbial evolution. Ch. 15 – Microbial Mechanisms of Pathogenicity 1. Pathogenesis: ○ Pathogenicity: Ability to cause disease. ○ Virulence: Degree of pathogenicity. ○ Virulence factors: Adherence (adhesins), enzymes (coagulase, hyaluronidase), antigenic variation, biofilms. 2. Host Interaction: ○ ID50: Dose required to infect 50% of a population. ○ Biofilm: Protective community of microbes. 3. Toxins: ○ Exotoxins: Protein toxins, specific effects (e.g., A-B toxins). ○ Endotoxins: Lipopolysaccharides from Gram-negative bacteria; trigger inflammation. Ch. 20 – Antimicrobial Drugs 1. Antibiotics and Antimicrobials: ○ Natural, semi-synthetic, and synthetic antibiotics. ○ Selective toxicity: Targeting microbial processes without harming the host. ○ Spectrum: Broad-spectrum vs. narrow-spectrum antibiotics. 2. Mechanisms of Action: ○ Common targets: Cell wall synthesis, protein synthesis, DNA/RNA synthesis, metabolic pathways.  ○ Beta-lactam antibiotics: Inhibit peptidoglycan synthesis by binding transpeptidase. 3. Antibiotic Testing: ○ MIC (Minimum Inhibitory Concentration): Lowest concentration that inhibits growth. ○ Kirby-Bauer Method: Antibiotic susceptibility testing via diffusion. 4. Antibiotic Resistance: ○ Mechanisms: Efflux pumps, enzyme production (e.g., beta-lactamase), target modification. ○ Slowing resistance: Appropriate prescribing, patient adherence, combination therapies.