1. Domain Bacteria is a group of single-celled, _____________________ microorganisms commonly known as bacteria or eubacteria. A prokaryote is a single-celled organism with no nucleus or membrane-bound organelles.

Domain Bacteria are prokaryotic microorganism that people see on a regular basis. A prokaryote can be defined as a uni-cellular organism that lacks a mitochondria, nucleus, or any other membranous organs. Prokaryotes are majorly divided into two different domains, Bacteria and Archaea. Prokaryotes are asexual organism which reproduces without any fusion of gametes. reproducing without fusion of gametes and uses binary fission for reproduction.

Prokaryotes have a more primitive prokaryotic cytoskeleton that involves actin and tubulin equivalents (MreB and FtsZ) along with the helically organised flagellum building block. flagellin, is an important cytoskeletal proteins that provides the basic cell physiological response of bacteria.

Prokaryotic cells are basically divided in four categories on the basis of various shapes such as:

Cocci – Bacteria having spherical or ovoid in shape e.g. Streptococcus.
Bacilli/Rod – Bacteria having cylindrical shape.
Spiral bacteria – Bacteria with spiral shapes.
Vibrio – Bacteria with comma-shape.

Hence, Domain Bacteria is a group of single celled, Prokarotic microorganism.