Micro Final

Vocabulary-style flashcards covering broad topics from microbiology lecture notes (organism categories, cell structures, viruses, antimicrobials, epidemiology, and representative diseases).

Categories of microorganisms

Major groups include bacteria, archaea, fungi, protozoa, algae, and viruses; organized as prokaryotes or eukaryotes.

Prokaryote vs. Eukaryote

Prokaryotes lack a true nucleus and membrane-bound organelles; eukaryotes have a nucleus and membrane-bound organelles.

Pathogen

A microorganism capable of causing disease in a host.

Benefits of microbes

Contribute to digestion, nutrient cycling, food production, biotechnology, and overall health of ecosystems and hosts.

Louis Pasteur and the Swan Neck Experiment

Demonstrated biogenesis: microorganisms arise from other microorganisms, not spontaneously; disproved abiogenesis.

Abiogenesis vs Biogenesis

Abiogenesis: life arising from nonliving matter; Biogenesis: life arising from existing life.

Lister, Holmes, Semmelweis (contributions)

Lister—antiseptic surgery; Holmes (Oliver Wendell Holmes Sr.)—hand hygiene to prevent puerperal fever; Semmelweis—handwashing to reduce childbed fever.

Organic compounds (in biology)

Carbon-containing molecules fundamental to life, including carbohydrates, lipids, proteins, and nucleic acids.

Bacterial cell parts (basic)

Key parts include cell wall, cytoplasmic membrane, ribosomes, nucleoid, capsule (in some), flagella, fimbriae/pili.

Bacterial shapes

Cocci (spherical), Bacilli (rod-shaped), Vibrios (curved rods), Spirilla (spiral rigid), Spirochetes (helical).

Bacterial arrangements

Diplococci, Streptococci, Staphylococci, Sarcinae, tetrads—patterns of grouping.

External structures of bacteria

Flagella (motility), Fimbriae (attachment), Pili (conjugation and transfer).

Bacterial flagellar arrangement

Monotrichous, Lophotrichous, Amphitrichous, Peritrichous.

Glycocalyx (functions)

Capsule or slime layer that protects bacteria and aids adherence to surfaces.

Glycocalyx types

Capsule (dense) and Slime layer (loose, flexible).

Bacterial cell wall functions

Provides shape and protection; contains peptidoglycan (basis for Gram stain).

Gram staining overview

Differentiates bacteria by cell wall structure: Gram-positive (thick peptidoglycan) vs Gram-negative (outer membrane).

Gram staining steps

Crystal violet → iodine → alcohol decolorization → safranin counterstain.

Gram-positive vs Gram-negative antibiotic Susceptibility

Gram-positive often more susceptible to many cell-wall–targeting antibiotics; Gram-negative have an outer membrane that can impede drug entry.

Cytoplasmic (cell) membrane functions

Selective permeability, energy production, transport of nutrients and wastes.

Ribosomes (basic)

RNA-protein complexes where protein synthesis occurs; bacteria have 70S; eukaryotes have 80S ribosomes.

Eukaryotic microbes (basic)

Fungi, Protozoa, Algae; all are eukaryotic and contain membrane-bound organelles.

Eukaryotic organelle functions (overview)

Rough ER (protein synthesis), Smooth ER (lipid synthesis), Golgi (modification/packaging), mitochondria (energy).

Fungal characteristics

Chitin in cell walls; ergosterol in membranes; heterotrophic and saprophytic.

Fungal nutrition requirements

Chemoorganotrophs; require organic carbon and energy sources.

Fungal reproduction

Asexual (budding, spore formation) and sexual (spore formation under stress).

Protozoal cellular characteristics

Unicellular eukaryotes; diverse morphologies; often motile; may form cysts.

Protozoal nutrition requirements

Typically heterotrophic; acquire nutrients by ingestion or phagocytosis.

Protozoal life cycle stages

Cyst (dormant) and Trophozoite (active).

Helminth types

Flatworms (trematodes, cestodes) and roundworms (nematodes).

Helminth life cycle stages

Egg, larva, and adult stages.

Helminth reproduction

Sexual reproduction with eggs released to the environment; complex life cycles.

General viral characteristics

Acellular (not cells); require host cells to replicate; can be naked or enveloped.

Viral structure/shape

Icosahedral, helical, or complex symmetry; nucleic acid inside a protein capsid.

Viral components

Genome (RNA or DNA), capsid, and sometimes an envelope and tegument proteins.

Capsid subunits

Capsomeres—the protein subunits that assemble into the capsid.

Naked vs enveloped viruses

Naked viruses lack a lipid envelope; enveloped viruses have a host-derived lipid envelope.

Viral nucleic acids

DNA or RNA (single- or double-stranded; may be segmented; positive- or negative-sense).

Viral multiplication stages

Attachment/adsorption, entry/penetration, uncoating, replication, assembly, release.

Common cytopathic effects of viruses

Cell rounding, syncytia formation, inclusion bodies, cell lysis.

Lysogeny (lysogenic conversion)

Phage DNA integrates into host genome as a prophage; can alter host properties.

Latency

Dormant viral infection with potential reactivation later.

Oncoviruses (examples)

Human papillomavirus (HPV), Epstein–Barr virus (EBV), hepatitis B virus (HBV) as examples.

Bacteriophages

Viruses that specifically infect bacteria.

In vivo vs. in vitro

In vivo: inside a living organism; in vitro: outside an organism, e.g., in culture.

Prion

Infectious misfolded protein causing neurodegenerative diseases; lacks nucleic acid.

Prion infections (examples)

Creutzfeldt–Jakob disease (CJD), Gerstmann–Sträussler–Scheinker syndrome, Fatal familial insomnia.

Satellite viruses and viroids

Satellite viruses require helper virus; viroids are small pathogenic RNA genomes in plants.

Antimicrobial ideal properties

Low toxicity to host, high selectivity, stability, broad/narrow spectrum as needed, and good pharmacokinetics.

Selective toxicity

Drugs target microbial processes not present or significantly different in the human host.

Narrow-spectrum vs broad-spectrum

Narrow-spectrum target a limited range of microbes; broad-spectrum target a wide range of microbes.

5 drug categories by MOA (overview)

1) Cell wall synthesis inhibitors; 2) Protein synthesis inhibitors; 3) Nucleic acid synthesis inhibitors; 4) Antimetabolites; 5) Membrane-disrupting agents.

Penicillin (MOA category)

Inhibits bacterial cell wall synthesis (beta-lactam) and is primarily active against Gram-positive bacteria.

Azoles (MOA category)

Inhibit fungal cytochrome P450 enzymes to disrupt ergosterol synthesis.

Metronidazole (MOA category)

Property of antimicrobial with activity against anaerobes and some protozoa; causes DNA damage.

Albendazole/Mebendazole (MOA category)

Systemic or luminal anthelmintics that disrupt parasite microtubules and glucose metabolism.

5 resistance mechanisms (overview)

Enzymatic drug inactivation; altered drug target; decreased permeability; efflux pumps; biofilm protection.

Probiotics

Live microorganisms that confer a health benefit to the host when administered in adequate amounts.

Prebiotics

Substances that foster growth or activity of beneficial microorganisms in the host.

Superinfections

New infections that occur when normal microbiota are disrupted, allowing opportunistic pathogens to flourish.

Human microbiome

The ensemble of microorganisms living in and on the human body; influences health and disease.

Normal biota acquisition

Colonization occurs via birth canal, contact with caregivers, environment, diet, and ingestion of microbes.

Areas of body with microbes present

Skin, oral cavity, GI tract, respiratory tract, genitourinary tract, and mucosal surfaces.

Infection vs disease

Infection is colonization by a microbe; disease results from the host's response causing symptoms.

Polymicrobial infections

Infections involving multiple microbial species, often more difficult to treat.

5 steps leading to infection and disease

Portal of entry, attachment to host, surviving host defenses, causing disease, portal of exit.

Virulence vs pathogenicity vs pathogenesis

Virulence: degree of harm a microbe can cause; pathogenicity: ability to cause disease; pathogenesis: development and progression of disease.

Endotoxin vs exotoxin

Endotoxins are LPS components released by Gram-negative bacteria; exotoxins are secreted proteins by bacteria.

Patterns of infection

Acute, chronic, latent, recurrent, or persistent infections; varying onset and duration.

Signs, symptoms, syndrome

Signs are objective findings; symptoms are subjective experiences; syndrome is a group of symptoms; latency: dormant period; sequelae: aftereffects.

Incubation period

Time between exposure to a pathogen and first signs or symptoms.

Prodromal stage

Early non-specific symptoms before the characteristic signs of disease appear.

Acute phase

Period of rapid symptom development and peak disease severity.

Convalescent period

Recovery phase with diminishing symptoms.

Continuation period

lingering or persistent symptoms following acute illness.

Reservoir

Source from which a pathogen is maintained (humans, animals, environment).

Transmitter

Agent that physically passes a pathogen from reservoir to host (e.g., vector).

Carrier

Individual harboring and capable of transmitting a pathogen without showing signs of disease.

Zoonosis

Disease that can be transmitted from animals to humans.

Modes of transmission

Direct contact, indirect contact, mechanical and biological transmission.

Nosocomial infections

Hospital-acquired infections; commonly include urinary tract infections, pneumonia, and surgical site infections.

Koch's postulates

1) Pathogen present in diseased hosts; 2) isolate pathogen and grow in culture; 3) inoculate and reproduce disease in new host; 4) re-isolate and identify.

Prevalence vs incidence

Prevalence: total cases in a population at a time; incidence: new cases over a period.

Epidemiology, epidemic, endemic, sporadic, pandemic

Epidemiology: study of disease distribution and determinants; epidemic: sudden increase; endemic: persistent in a region; sporadic: occasional; pandemic: worldwide.

MRSA

Methicillin-resistant Staphylococcus aureus; resistant to many beta-lactam antibiotics; causes skin infections, pneumonia, sepsis.

Measles

Rubeola; highly contagious Viral disease with fever, rash, cough, conjunctivitis; vaccine-preventable.

Impetigo

Superficial skin infection by Staphylococcus aureus or Streptococcus pyogenes; crusted lesions.

Chickenpox/Shingles (varicella-zoster)

Viral infection with varicella; reactivation causes shingles (herpes zoster) with dermatomal rash.

Ringworm (Tinea infections)

Fungal skin infections caused by dermatophytes (e.g., Trichophyton, Microsporum).

Conjunctivitis

Inflammation of the conjunctiva; infectious etiologies include bacteria and viruses; contagious.

Meningitis (Neisseria meningitidis)

Inflammation of meninges; Neisseria meningitidis is a common cause; rapid diagnosis and treatment essential.

Neonatal meningitis

Meningitis occurring in newborns, often due to group B Streptococcus or E. coli; requires early treatment.

Acute vs subacute encephalitis

Acute encephalitis: rapid onset CNS inflammation; subacute: slower onset with milder symptoms.

Rabies

Rabies virus; neurotropic infection transmitted by animal bite; nearly always fatal without timely post-exposure prophylaxis.

Tetanus

Clostridium tetani toxin causes muscle rigidity and spasms; preventable by vaccination and proper wound care.

Botulism (3 types)

Foodborne, infant, and wound botulism; caused by botulinum toxin that blocks neurotransmitter release.

Malaria

Protozoan disease transmitted by Anopheles mosquitoes; causes fever, chills, anemia; treated with antimalarials.

Sepsis

Systemic inflammatory response to infection; can progress to septic shock; rapid recognition essential.

Lyme disease

Tickborne illness caused by Borrelia burgdorferi; rash, fever, arthralgias; treat with appropriate antibiotics.

Pharyngitis

Inflammation of the pharynx; can be viral or bacterial (e.g., Streptococcus pyogenes).