Microorganisms, Viruses, Bacteria, Protists, and Fungi Vocabulary

Vocabulary terms and definitions covering Domain Archaea, Bacteria, Protists, Fungi, and nonliving Viruses based on lecture notes.

Microorganisms

Organisms that are so small that a microscope is needed to see them.

Protists

Organisms classified in Domain Eukarya that are simpler than the plants, animals, and fungi they are grouped with.

Archaea

Unicellular microorganisms without a nucleus that often live in extreme conditions and make food from chemicals.

Autotrophs

Organisms that can make their own food.

Heterotrophs

Organisms that must find their food rather than making it themselves.

Decomposers

Organisms that absorb nutrients from decaying organisms.

Virus

A tiny, nonliving particle that enters and then reproduces inside a living cell.

Nanometers

Units of measurement equal to one billionth of a meter ($1 \times 10^{-9}\text{ m}$), used to measure viral particles.

Host

An organism that provides a source of energy or a suitable environment for a virus or parasite to live.

Vaccine

A substance used in vaccination consisting of weakened or killed pathogens that trigger the body to produce chemicals that destroy the pathogens.

Epidemic

An outbreak that occurs when a virus sickens many people at the same time within a limited geographic area.

Toxins

Dangerous chemicals given off by infectious bacteria that damage surrounding cells and tissues.

Prokaryotes

Single-celled organisms that lack a nucleus.

Cell Wall

A structure in bacterial cells that protects them from attacks and keeps them from drying out.

Cell Membrane

A structure located inside the cell wall of bacteria that controls what substances pass into and out of the cell.

Flagella

Structures attached to the cell wall of some bacteria that whip around like propellers to drive the cell toward food.

Cytoplasm

Everything inside the cell membrane.

Pili

Tiny hairs on bacterial cells that help the cell move and reproduce.

Ribosomes

Round structures inside bacterial cells where proteins are made.

Endospore

A thick-walled shell that forms around genetic material and cytoplasm in some bacteria to allow survival during harsh conditions.

Binary Fission

A form of asexual reproduction in bacteria where a cell grows larger and then divides into two identical cells.

Conjugation

A process where two bacterial cells come together and exchange genetic material without producing more bacteria.

Parasites

Organisms that benefit from living with, on, or in a host.

Hyphae

Threadlike tubes into which fungal cells are arranged, providing structure and releasing chemicals to break down and absorb food.

Fruiting Bodies

Reproductive structures produced by fungi that produce spores carried by wind or water to new locations.

Mycorrhiza

A fungal structure that grows around plant seeds and roots, supplying water to the plant in exchange for plant sugars.