Unit 2 & 3: Bacteria and Viruses Study Guide

Vocabulary flashcards covering the key terms, structures, processes, and differences related to bacteria, archaea, and viruses based on the Unit 2 & 3 study guide.

Three Domains of Life

The three overarching domains that classify living organisms: Bacteria, Archaea, and Eukarya.

Prokaryotic Cell

A cellular organism, such as those found in the domains Eubacteria and Archaea, characterized by having no nucleus.

Eukaryotic Cell

A type of cell characterized by the presence of a nucleus.

Bacterial Cell Membrane

A barrier composed of lipid and protein that encloses the bacterial cell.

Capsule

An extra outer membrane found in some bacteria that provides protection against antibiotics.

Flagella

Bacterial structures that spin like a propeller to provide motility.

Plasmid

Extra DNA used to help bacteria adapt quickly in case of environmental stress.

Ribosomes

Structures in bacterial cells responsible for carrying out protein synthesis.

Coccus

A bacterium with a spherical shape.

Bacillus

A bacterium with a rod shape.

Spirillum

A bacterium with a spiral shape.

Extremophile

Bacteria or archaea that thrive in extreme habitats under harsh conditions, such as hot springs, the Dead Sea, high salt, or acidic environments.

Binary Fission

A form of asexual reproduction in bacteria where the DNA replicates, the cell elongates, DNA copies separate, a septum forms, and the cell divides, doubling the population size with each division.

Horizontal Gene Transfer

The process through which bacteria acquire DNA from other organisms, allowing traits such as antibiotic resistance genes to be shared and spread.

Decomposition

A bacterial role that breaks down organic material, which is essential for new growth.

Antibiotic

Substances that target bacteria but do not work against viruses because viruses have different structures and reproduction methods.

Virus

Infectious particles that depend on host cells to reproduce, lacking cellular organelles and the ability to carry out metabolism on their own.

Capsid

The protective protein coat that encloses the viral genetic material (DNA or RNA).

Viral Envelope

An outer structure that surrounds the capsid of some viruses.

Lytic Cycle

A viral replication cycle consisting of attachment, entry, replication, assembly, and release that produces many new viruses and destroys the host cell by breaking it open.

Lysogenic Cycle

A viral replication cycle in which viral genetic material becomes incorporated into the host's DNA and replicates without immediately killing the host cell.