Microbiology Chapter 1-3 Key Concepts and Structures

Microorganism

Living organisms too small to see without magnification, including bacteria, viruses, fungi, protozoa, and algae.

Microbe

Another term for microorganism.

Pathogen

An organism that causes disease in healthy hosts.

Opportunistic pathogen

An organism that causes disease only when the host's defenses are weakened.

Biogenesis

The theory that life comes from pre-existing life.

Spontaneous generation

The theory that life arises from non-living matter.

Koch's postulates

(1) Microbe present in diseased but not healthy hosts; (2) Isolate and culture the microbe; (3) Inoculate healthy host to cause disease; (4) Re-isolate the same microbe.

Germ theory

The theory that microbes are the cause of diseases.

Aseptic technique

A set of practices aimed at preventing contamination by unwanted microbes.

Louis Pasteur

Scientist known for disproving spontaneous generation through swan-neck flask experiments.

Candida albicans

A type of yeast that can be considered an opportunistic pathogen.

Normal microbiota

Microbes that normally inhabit the body and can become opportunistic under certain conditions.

Sterilized broth

Broth that has been treated to eliminate all living microorganisms.

Air contaminants

Unwanted microorganisms present in the air that can contaminate sterile environments.

Immunocompromised individuals

People whose immune systems are weakened, making them more susceptible to opportunistic infections.

Diseased hosts

Hosts that are affected by a disease caused by pathogens.

Healthy hosts

Hosts that are not affected by disease.

Microbial culture

The process of growing microorganisms in controlled conditions.

Inoculation

The introduction of a microbe into a host to study its effects.

Clear broth

Broth that remains free of turbidity, indicating no microbial growth.

Contamination

The presence of unwanted microorganisms in a sample or environment.

Healthcare facilities

Places such as hospitals where aseptic techniques are crucial to prevent infections.

Laboratories

Controlled environments where scientific experiments are conducted, requiring aseptic techniques.

Antiseptics

Substances that prevent the growth of disease-causing microorganisms.

Hygiene

Practices that promote health and prevent disease by maintaining cleanliness.

Taxonomic hierarchy

The classification system that organizes living organisms into categories such as domain, kingdom, phylum, class, order, family, genus, and species.

Domain

The highest taxonomic rank, which includes Bacteria, Archaea, and Eukarya.

Kingdom

A rank in the taxonomic hierarchy, with kingdoms in Eukarya including Animalia, Plantae, Fungi, and Protista.

Binomial nomenclature

A system for naming organisms using two terms: the genus name (capitalized) and the species name (lowercase), both italicized.

Species

A group of similar organisms that can reproduce and interchange genes.

Strain

A subgroup within a species that has distinct traits, such as antibiotic resistance.

Parasitism

A symbiotic relationship where one organism benefits at the expense of the host.

Mutualism

A symbiotic relationship where both organisms benefit.

Commensalism

A symbiotic relationship where one organism benefits and the other is unaffected.

Puerperal fever

A bacterial infection that can occur in women after childbirth, historically reduced by handwashing.

Extremophiles

Organisms that thrive in extreme environmental conditions, classified under the domain Archaea.

E. coli

A common bacterium found in the intestines of humans and animals, often used as an example in microbiology.

Escherichia coli

The full binomial name for E. coli, indicating its genus and species.

Skin bacteria

Microorganisms that live on the skin, often in a commensal relationship with humans.

Nitrogen-fixing bacteria

Bacteria that convert atmospheric nitrogen into a form usable by plants, demonstrating mutualism.

Malaria parasite

An example of a parasitic relationship, where the parasite benefits at the expense of the host.

Epiphytic plants

Plants that grow on other plants but do not harm them, exemplifying commensalism.

Timeline contributions

A method to visually represent the historical contributions of figures like Semmelweis, Lister, and Nightingale to healthcare.

Comparison table

A structured way to compare different categories or concepts, such as domains in microbiology.

Application questions

Questions that require the application of knowledge to specific scenarios, such as naming conventions or classification.

Roles of normal microbiota

Compete with pathogens, aid digestion, produce vitamins, train immune system.

Biofilm

Formation: Attachment to surface, microcolony growth, matrix production, maturation.

Healthcare implications of biofilms

Resistant to antibiotics/antiseptics; cause chronic infections (e.g., on catheters).

Bioremediation

Microbial process used to clean up contaminated environments.

Fermentation

Microbial process used in the production of beer and yogurt.

Culture media

Broth (liquid), agar (solid/semi-solid).

Aseptic culture

Goal: Transfer microbes without contamination.

Streak plate technique

Goal: Isolate individual colonies from mixed samples.

Simple stain

One dye, shows shape/size (e.g., methylene blue).

Structural stain

Multiple dyes/steps, highlights structures (e.g., endospore stain).

Extracellular matrix

A network of proteins and polysaccharides that provide structural and biochemical support to surrounding cells.

Nutrient media

Type of culture media that supports the growth of a wide variety of microorganisms.

Selective media

Type of culture media that inhibits the growth of certain microbes while allowing others to grow.

Differential media

Type of culture media that distinguishes between different types of microbes based on their biological characteristics.

Microcolony growth

The stage in biofilm formation where clusters of bacteria multiply.

Chronic infections

Infections that persist over a long period of time, often associated with biofilms.

Oxygen production

A process carried out by algae and other photosynthetic microbes contributing to the environment.

Nutrient cycling

The movement and exchange of organic and inorganic matter back into the production of living matter.

Gram stain procedure

Involves steps: Crystal violet, iodine, alcohol decolorizer, safranin; works due to cell wall differences.

Gram-positive cell

Has a thick peptidoglycan layer that retains purple color during Gram staining.

Gram-negative cell

Has a thin peptidoglycan layer that loses color and stains pink during Gram staining.

Compound light microscope

An optical instrument used to magnify small objects using multiple lenses.

Resolution

Ability to distinguish two close points as separate, measured in nanometers (nm).

Numerical aperture (NA)

A measure that indicates the light-gathering ability of a lens.

Atomic number

The number of protons in an atom.

Atomic mass

The sum of protons and neutrons in an atom, approximately.

Chemical symbol

An abbreviation for an element, such as C for carbon.

Proton

A positively charged particle found in the nucleus of an atom.

Neutron

A neutral particle found in the nucleus of an atom.

Electron

A negatively charged particle that orbits the nucleus of an atom.

Ionic bond

A bond formed by the transfer of electrons from one atom to another.

Covalent bond

A bond formed by the sharing of electrons between atoms.

Hydrogen bond

A weak attraction between a hydrogen atom and an electronegative atom.

Polarity

The distribution of electrical charge over the atoms in a molecule.

Cohesion

The attraction between molecules of the same substance.

Acid

A substance that donates protons (H+) in a solution.

Base

A substance that accepts protons (H+) in a solution.

Salt

An ionic compound formed from the neutralization reaction of an acid and a base.

pH

A measure of the acidity or basicity of a solution, on a scale from 0 to 14.

Organic

Contain carbon (e.g., proteins, carbs).

Inorganic

Lack carbon or simple C compounds (e.g., water, CO2).

Functional group

Specific atom groups conferring properties (e.g., -OH alcohol, -COOH carboxyl).

Amino acid

Building blocks of proteins (20 types).

Peptide bond

Linkage between amino acids in proteins.

Nucleotide

Building blocks of nucleic acids: Sugar (ribose/deoxyribose), phosphate, base (A, T/U, G, C).

DNA

Deoxyribonucleic acid, uses deoxyribose sugar.

RNA

Ribonucleic acid, uses ribose sugar.

Prokaryote

Single-celled organism without a nucleus.

Pleomorphic

Variable shapes (e.g., Mycoplasma).

Monomorphic

Fixed shape (e.g., E. coli rods).

Surface-to-volume ratio

High ratio for efficient nutrient uptake/waste removal.

Coccus

Spherical shape of bacteria.

Bacillus

Rod-shaped bacteria.

Spirillum

Spiral-shaped bacteria.

Diplo-

Arrangement of bacteria in pairs.