Introduction to Microbiology and Cell Biology Concepts

Microbiota

The community of microorganisms living in a particular environment, such as the human gut.

Taxonomy

The science of classifying organisms.

Genus

A group of closely related species.

Atomic nucleus

The center of an atom, containing protons and neutrons.

Electron shell

Energy levels where electrons orbit around the nucleus.

Compound

A substance formed when two or more different elements combine.

Molecule

Two or more atoms bonded together.

Ionic bond

A chemical bond formed by the transfer of electrons between atoms, creating charged ions.

Salt/ionic compound

A compound resulting from the formation of an ionic bond.

Ion

An atom or molecule with a net electric charge due to the loss or gain of electrons.

Organic molecule

A carbon-based molecule, usually found in living organisms.

Polar covalent bond

A covalent bond in which electrons are not shared equally, creating partial charges.

Nonpolar molecule

A molecule in which the electrons are distributed more evenly.

Solvent

The substance in which the solute dissolves (e.g., water).

Solute

The substance that is dissolved in a solvent.

Amphipathic

Molecules that have both hydrophilic and hydrophobic regions (e.g., phospholipids).

Polymer

A large molecule formed by the bonding of many monomers.

Monosaccharides

Simple sugars (e.g., glucose).

Polysaccharides

Carbohydrates made up of many sugar molecules (e.g., starch, cellulose).

Starch

A polysaccharide that stores energy in plants.

Microbe/microorganism

A microscopic organism such as bacteria, viruses, or fungi.

Eukaryote

Organism with a nucleus and membrane-bound organelles (e.g., plants, animals, fungi).

Bacteria

Single-celled microorganisms that lack a nucleus.

Archaea

Single-celled microorganisms similar to bacteria but with distinct biochemical and genetic characteristics.

Eukarya

Domain that includes all eukaryotic organisms (organisms with a nucleus).

Metabolism

The chemical processes that occur within a living organism to maintain life.

Pathogen

An organism that can cause disease.

Species

The most specific classification of organisms, defined by their ability to interbreed and produce viable offspring.

Atom

Basic unit of matter, made of protons, neutrons, and electrons.

Proton

Positively charged subatomic particle in the nucleus of an atom.

Neutron

Neutral subatomic particle in the nucleus of an atom.

Electron

Negatively charged particle that orbits the nucleus of an atom.

Chemical bond

Attraction between atoms that allows the formation of chemical substances.

Element

A substance that cannot be broken down into simpler substances by chemical means.

Atomic symbol

A one- or two-letter abbreviation that represents an element.

Atomic number

The number of protons in the nucleus of an atom, which defines the element.

Atomic mass

The total number of protons and neutrons in an atom's nucleus.

Covalent bond

A chemical bond formed by the sharing of electrons between atoms.

Hydrogen bond

A weak bond between a hydrogen atom and another atom with a partial negative charge.

Anion

A negatively charged ion (gains electrons).

Cation

A positively charged ion (loses electrons).

Nonpolar covalent bond

A covalent bond in which electrons are shared equally.

Polar molecule

A molecule with a partial positive charge on one side and a partial negative charge on the other.

Solution

A mixture in which one or more substances are uniformly distributed in another substance.

Aqueous solution

A solution in which the solvent is water.

Concentration

The amount of solute in a given volume of solution.

Hydrophilic

Attracted to water (water-loving).

Hydrophobic

Repels water (water-fearing).

pH

A scale used to measure the acidity or basicity of a solution.

Acidic

Having a pH less than 7; high concentration of hydrogen ions (H+).

Basic/alkaline

Having a pH greater than 7; low concentration of hydrogen ions (H+).

Neutral pH

pH of 7, indicating an equal concentration of H+ and OH-.

Macromolecule

A large complex molecule, such as proteins, nucleic acids, carbohydrates, and lipids.

Monomer

A simple compound whose molecules can join together to form polymers.

Carbohydrates

Organic compounds that serve as a major source of energy (e.g., sugars, starches).

Disaccharides

Sugars composed of two monosaccharides (e.g., sucrose).

Glucose

A simple sugar that is an important energy source in living organisms.

Cell

Basic structural and functional unit of life.

Prokaryote

Single-celled organism without a nucleus (e.g., bacteria, archaea).

The Three Domains

The highest level of classification: Bacteria, Archaea, Eukarya.

Lipids

Organic molecules that are not soluble in water, including fats, oils, and phospholipids.

Phospholipids

A type of lipid that makes up the cell membrane.

Proteins

Large molecules made of amino acids that perform a variety of functions in cells.

Amino acids

The building blocks of proteins.

Nucleic acids

DNA and RNA, which store and transmit genetic information.

Nucleotides

The building blocks of nucleic acids (composed of a sugar, phosphate group, and nitrogenous base).

Coccus/cocci

Spherical bacterial shape.

Bacillus/bacilli

Rod-shaped bacterial cells.

Vibrio

Comma-shaped bacteria.

Spirillum/spirilli

Spiral-shaped bacteria.

Spirochete

Thin, flexible spiral-shaped bacteria.

Strepto-

Chain-like arrangement of cells.

Staphylo-

Cluster-like arrangement of cells.

Cell envelope

Includes cell wall, cell membrane, and outer structures.

Peptidoglycan

A molecule that provides strength to the bacterial cell wall.

Gram-positive cell

Bacteria with a thick peptidoglycan cell wall.

Gram-negative cell

Bacteria with a thin peptidoglycan layer and outer membrane.

Endospore

A tough, dormant structure formed by some bacteria for survival in extreme conditions.

Nucleus

Organelle containing genetic material in eukaryotic cells.

Organelle

Specialized structures within eukaryotic cells.

Mitochondria

The powerhouse of the cell, producing energy (ATP).

Fungi

Eukaryotic organisms that include yeasts and molds.

Chitin

A structural substance in fungal cell walls.

Yeasts

Single-celled fungi that reproduce by budding.

Molds

Multicellular fungi composed of hyphae.

Virus

A non-cellular infectious agent.

Host cell

The living cell in which a virus replicates.

Capsid

The protein coat surrounding the genetic material of a virus.

Capsomere

Protein subunits that make up the capsid.

Nucleic acid

Genetic material in a virus, either DNA or RNA.

Lytic cycle

A process in which the virus replicates and causes the host cell to burst.

Lysogenic cycle

A viral replication cycle in which the virus integrates into the host genome and remains dormant.

Archaea

Doesn’t contain pathogenic microbes

Taxonomy

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species