Microbiology WGU OA

Prokaryotic Cells

Lack nucleus membrane, single-celled, lack membrane-bound organelles.

Eukaryotic Cells

Contain nucleus membrane, genetic material in nucleus, multicellular, membrane-bound organelles.

Ribosomes in Cells

Prokaryotic: free 80s, Eukaryotic: attached to Rough ER 70s.

Endospores

Protect bacterial genome, survive harsh conditions, form during sporulation.

Chemotaxis

Movement with chemical gradient.

Phototaxis

Movement toward/away from light.

Bacterial Flagella

Promote movement in bacteria.

Fimbriae

Protein structures for cell attachment.

Pili

Similar to fimbriae, aid in attachment.

Vegetative Cells vs. Endospores

Typical cell state vs. dormant protective state.

Sporulation Process

Cells form endospores in hostile environments.

Gram-Negative Bacteria

Thin peptidoglycan layer, lipopolysaccharide in outer membrane.

Capsid in Viruses

Protein coat with genetic material.

Naked vs. Enveloped Virus

No envelope vs. phospholipid envelope.

Hyphae in Fungi

Filaments forming fungal body.

Mycelium

Network of hyphae in fungi.

Dimorphic Fungus

Changes appearance during life stages.

Ascomycota

Fungal species with ascospores.

Basidiomycota

Fungi producing basidiospores.

Microsporidia

Lack mitochondria, spores with polar tube.

Zygomycota

Saprophytic fungi with coenocytic hyphae.

Protozoans

Wide habitat range, free-living, parasitic, symbiotic.

Schizogony in Protozoans

Nucleus divides multiple times, forming merozoites.

Parasitic Helminths

Nematoda (roundworms) and Platyhelminthes (flatworms).

Monoecious vs. Dioecious

Both sexes vs. separate sexes for reproduction.

Nematoda Characteristics

Roundworms with distinct features.

Monoecious

Organisms with both male and female reproductive organs.

Dioecious

Organisms requiring two different individuals for reproduction.

Nematoda

Roundworms with 15,000 species, unsegmented, found in feces.

Flukes

Non-segmented Platyhelminthes with oral sucker for attachment.

Tapeworms

Segmented Platyhelminthes living in intestines.

Homolactic fermentation

Produces only lactic acid, important in food fermentation.

Heterolactic fermentation

Produces ethanol, acetic acid, CO2, used in souring vegetables.

Acetone-butanol-ethanol

Fermentation pathway for solvents, gasoline alternative.

Butanediol

Fermentation pathway for Chardonnay wine production.

Butyric acid

Fermentation pathway for butter production.

Lactic acid

Fermentation pathway for sauerkraut, yogurt, and cheese production.

Mixed acid

Fermentation pathway for vinegar, cosmetics, and pharmaceuticals.

Proprionic acid

Fermentation pathway for Swiss cheese production.

Bioremediation

Using microbes to remove pollutants, xenobiotics from the environment.

Gene therapy

Correcting gene abnormalities using viral vectors.

Synthetic antimicrobials

Chemically derived antimicrobials not found in nature.

Natural antibiotics

Antibiotics derived from natural sources.

Semisynthetic antimicrobial

Synthetically modified antibiotic derived from natural sources.

Pathogenicity

Microbe's ability to cause disease or illness.

Virulence

Degree of pathogenicity of a microbe.

Median infectious dose

Number of pathogen cells causing disease in 50% of animals.

Median lethal dose

Amount of pathogen or toxin killing 50% of infected animals.

Primary pathogens

Cause disease regardless of host's immune system.

Opportunistic pathogens

Exploit weakened host defenses to cause disease.

Virulence factors

Microbial factors determining pathogenicity.

Antigenic variation

Pathogen's surface protein changes to evade immune recognition.

Antigenic drift

Gradual changes in influenza virus surface proteins.

Antigenic shift

Major changes in influenza virus surface proteins.

Mycotoxins

Toxins produced by fungi affecting health.

Virulence factors (fungi)

Factors like adhesins, mycotoxins aiding fungal pathogenicity.

Virulence (protozoan pathogens)

Adhesion mechanisms aiding protozoan pathogenicity.

Virulence (helminths)

Complexity making helminths hard to eliminate once inside host.

Bacteremia

Presence of bacteria in the bloodstream.

Septicemia

Pathogens multiplying in the bloodstream.

Viremia

Presence of viruses in the bloodstream.

Toxemia

Presence of toxins in the bloodstream.

Exoenzymes

Extracellular enzymes aiding pathogen invasion and growth

Glycohydrolases

Enzymes degrading connective tissue for pathogen spread

Nucleases

Enzymes degrading extracellular DNA for pathogen spread

Phospholipases

Enzymes degrading cell membrane phospholipids

Proteases

Enzymes digesting proteins

Collagenase

Enzyme degrading collagen; e.g., Clostridium perfringens

DNAse

Enzyme degrading DNA; e.g., Staphylococcus aureus

Hyaluronidase

Enzyme degrading hyaluronic acid; e.g., Streptococcus pyogenes

Toxins

Harmful substances affecting cells; toxigenicity is toxin production ability; two types: endotoxins and exotoxins

Endotoxins

Produced by gram-negative bacteria, trigger immune response

Exotoxins

Proteins from pathogenic bacteria causing specific effects

Biofilms

Structured microbial communities aiding microorganisms

EPS

Extracellular polymeric substances in biofilms

Planktonic cell

Free-floating microbial cell

Sessile cell

Attached microbial cell

Quorum sensing

Cell response mechanism within biofilms

Coagulase

Enzyme inducing blood clotting

Light microscopy

Microscopy using visible light

Electron microscope

Microscope using electron beams

Gram staining

Staining technique to differentiate bacteria

Acid-fast stain

Staining technique for bacteria with waxy coats

Capsule staining

Staining technique highlighting bacterial capsules

Endospore staining

Staining technique identifying bacterial endospores

Microbiome

Microbial community in a specific environment

Extremophiles

Microorganisms thriving in extreme conditions

Rhizosphere

Soil region influenced by plant roots

Community

Interacting population in a specific area

Symbiosis

Close interaction between different species

Mutualism

Symbiotic relationship where both host and parasite benefit

Commensalism

Symbiotic relationship where one benefits without affecting the other

Parasitism

Symbiotic relationship where one benefits at the expense of the other

Resident microbiota

Microbes permanently present on or in the body, e.g., gut flora

Transient microbiota

Microbes temporarily present on or in the body, e.g., after travel

Infectious disease

Caused by pathogens, e.g., tuberculosis

Communicable disease

Capable of being spread, e.g., influenza

Contagious disease

Degree of spread of a communicable disease, e.g., measles

Iatrogenic disease

Disease contracted due to medical procedures, e.g., hospital-acquired infections

Nosocomial disease

Disease acquired in a hospital setting, e.g., MRSA infections