[proh-kar-ee-oht, -ee-uh t]
- any cellular organism that has no nuclear membrane, no organelles in the cytoplasm except ribosomes, and has its genetic material in the form of single continuous strands forming coils or loops, characteristic of all organisms in the kingdom Monera, as the bacteria and blue-green algae.
Origin of prokaryote
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- any organism having cells in each of which the genetic material is in a single DNA chain, not enclosed in a nucleus. Bacteria and archaeans are prokaryotesCompare eukaryote
from pro- ² + karyo- + -ote as in zygote
Word Origin and History for prokaryotes
Online Etymology Dictionary, © 2010 Douglas Harper
- An organism of the kingdom Prokaryotae, constituting the bacteria and cyanobacteria, characterized by the absence of a nuclear membrane and by DNA that is not organized into chromosomes.
- Any of a wide variety of one-celled organisms of the kingdom Monera (or Prokaryota) that are the most primitive and ancient known forms of life. Prokaryotes lack a distinct cell nucleus and their DNA is not organized into chromosomes. They also lack the internal structures bound by membranes called organelles, such as mitochondria. At the molecular level, prokaryotes differ from eukaryotes in the structure of their lipids and of certain metabolic enzymes, and in how genes are expressed for protein synthesis. Prokaryotes reproduce asexually and include the bacteria and blue-green algae. Also called moneran Compare eukaryote. See Table at taxonomy.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
It is thought that prokaryotes were the first cells to appear on Earth.
The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.