Microbiology Microorganisms

What are normal microbiota?

Microbes that live stably on or in the human body without causing disease under normal conditions.

Where microorganisms are found

Everywhere - in air, soil, water, surfaces, on/in the human body.

How does the number of microbes in the human body compare to human cells?

Roughly the same — the number of microbes is approximately equal to the total number of human body cells.

What are the beneficial roles of normal microbiota in humans?

Aid in digestion, synthesize vitamins, protect against pathogens.

How do microbes help in biofuels?

Microbes convert waste or plant material into ethanol or methane fuels.

What is bioremediation?

Using microbes to clean up toxic pollutants like oil, solvents, pesticides, or heavy metals.

How do microbes help in sewage treatment and composting?

They break down organic matter, recycle water in sewage, and turn waste into compost.

How are microbes used in agriculture?

Biocontrol, controlling plant pests and diseases naturally.

What foods do microbes make?

Vinegar, cheese, pickles, soy sauce, sauerkraut, wine, beer, bread, chocolate.

What food additives are produced by microbes?

Xanthan gum and other stabilizers.

How do microbes contribute to the pharmaceutical industry?

They produce antibiotics, anti-cancer drugs, and immunosuppressants.

How are microbes used in biotechnology?

Enzymes for digestive aids, recombinant hormones (insulin, growth hormone), immune modulators, and gene therapy tools.

How do viruses contribute to gene therapy?

Viruses deliver healthy genes to human cells; CRISPR/Cas from bacteria allows precise DNA editing.

pathogens

Microbes that cause diseases.

Transient microbes

fleeting microbe

opportunistic pathogens

Microbes that only cause disease when the host's defenses are weak.

healthcare-associated infections

Infections acquired while receiving treatment in a healthcare facility, often caused by resistant microbes.

bacteria classified as prokaryotes

Their DNA is not enclosed in a nuclear membrane.

bacteria cell type

Unicellular

bacteria reproduce

Binary fission.

main component of the bacterial cell wall

Peptidoglycan

shapes of bacteria

Bacillus (rod-shaped), coccus (spherical/ovoid), spiral (corkscrew/curved).

shape of bacillus

Rod-like shape.

shape of coccus

Spherical or ovoid shape.

shape of spiral bacteria

Corkscrew or curved shape.

How actinomycetes grow

Long filaments similar to filamentous molds.

bacteriology

The study of bacteria.

avermectins

Antibiotics produced by bacteria used to treat parasitic infections.

genus Streptomyces importance

They produce many antibiotics used in human medicine and agriculture.

fungi classified as eukaryotes

Their genetic material is enclosed by a nuclear membrane.

fungi cell type

Unicellular and multicellular

fungal cell walls made of

Chitin, glucans, mannans.

types of fungi

Yeast and molds.

cell type of yeasts

Unicellular fungi.

mold

Multicellular fungi that grow as filaments.

mycology

The study of fungi.

shape of yeast

Spherical or oval.

yeasts reproduce

Budding or binary fission.

Saccharomyces cerevisiae

A type of yeast humans use to make wine, beer, and bread (Brewer's Yeast).

What type of fungi is mold?

Filamentous fungi.

mycelia (mycelium)

A visible mass of fungal growth made of hyphae.

hyphae

Long, filamentous fungal cells.

molds reproduce

By producing a large number of spores.

molds produce

Antibiotics (penicillin) and other drugs, and are used in food production like Penicillium roqueforti.

mycoses

Diseases caused by fungi.

types of mycoses

Systemic, subcutaneous, cutaneous, superficial, opportunistic.

protozoa cell types

Unicellular and eukaryotic cells.

Where are protozoa commonly found?

In water and moist environments.

structures do protozoa use for movement

Cilia, flagella, pseudopods.

pseudopod

A temporary 'false foot' of cytoplasm used for movement and feeding (e.g., Amoeba).

four medically important protozoa and the diseases they cause.

Plasmodium → malaria, Entamoeba histolytica → amebic dysentery, Giardia duodenalis → giardiasis ('beaver fever'), Trichomonas vaginalis → urinary/genital tract infections.

What is the cell type of helminths?

Multicellular, eukaryotic animals.

What are parasitic helminths?

They live inside a host and often have specialized adaptations to survive and feed there.

What are the types of medically important parasitic helminths?

Tapeworms, flukes, roundworms.

What is the cell type of viruses?

Acellular, very small, only seen through an electron microscope. Have either DNA or RNA.

What are the layers of a virus?

A protein coat that surrounds viral nucleic acid and a lipid envelope sometimes enclosing the protein coat.

When are viruses considered alive?

Only when inside infecting a host cell to use its machinery to reproduce.

What organisms can viruses infect?

Bacteria (bacteriophages), plants, animals, and humans.

infectious disease

A disease caused by pathogenic microorganisms that can be transmitted from one host to another.

system of nomenclature

A two-part naming system (binomial nomenclature) used to identify organisms by genus and species.

genus in the naming system

The first part of a scientific name, always capitalized, representing a group of closely related species.

species (specific epithet) in the naming system

The second part of a scientific name, lowercase, identifying the exact species within a genus.

What are some medically important viruses?

Influenza virus, HIV, Oncoviruses, Ebola virus, SARS-CoV-2.