• Prokaryotic Vs Eukaryotic Worksheet Pdf
• List Of Differences Between Eukaryotes And Prokaryotes
• Difference Prokaryotic Cell Eukaryotic Cell

The key difference between eukaryotic and prokaryotic organisms is that the eukaryotic organisms have a true nucleus and membrane-bound organelles while the prokaryotic organisms lack a nucleus and membrane-bound organelles.

Prokaryotic Vs Eukaryotic Worksheet Pdf

All living organisms belong to two categories namely prokaryotes or eukaryotes. Prokaryotic organisms exhibit a simple cell organization while eukaryotic organisms show a complex cell organization. Moreover, prokaryotes are unicellular, and they lack a nucleus and membrane-bound organelles. On the other hand, eukaryotes are generally multicellular and contain a true nucleus and membrane-bound organelles such as chloroplasts, mitochondria and Endoplasmic reticulum, etc. Prokaryotes include bacteria and Archaea while eukaryotes include protists, fungi, plants and animals. Other than those above-mentioned differences, there are more differences between prokaryotes and eukaryotes. Therefore, understanding the differences between prokaryotic and eukaryotic organisms is very important. The aim of this article is to discuss the difference between eukaryotic and prokaryotic organisms.

Prokaryotic DNA is double­stranded and circular. But, eukaryotic DNA is. By Lakna. 9 min read 0 Main Difference – Chloroplast vs Mitochondria Chloroplast and mitochondria are two organelles found in the cell. The chloroplast is a membrane­bound organelle found only in algae and plant cells. English: Prokaryotic flagella run in a rotary movement, while eukaryotic flagella run in a bending movement. The prokaryotic flagella uses a rotary motor,and the eukaryotic flagella uses a complex sliding filament system. Eukaryotic flagella is ATP driven, while prokaryotes are proton driven.

CONTENTS

1. Overview and Key Difference
2. What is Eukaryotic
3. What is Prokaryotic
4. Similarities Between Eukaryotic and Prokaryotic
5. Side by Side Comparison – Eukaryotic vs Prokaryotic in Tabular Form
6. Summary

What is Eukaryotic?

Eukaryotic organisms have organized cells with membrane-bound organelles with defined nuclei. All plants, animals, fungi, protozoa and algae are eukaryotic organisms. They have 80S large ribosomes in the cytoplasm that act as the sites for proteins synthesis. And also they have mitochondria, Golgi bodies, ER, and chloroplast, etc. Hence, the nuclear envelope is the most defining characteristic of all eukaryotic organisms. Nuclear membrane encloses the nucleus of eukaryotes. The genome of the eukaryotes is tightly bound with histone proteins and packaged into chromosomes which are highly organized complex structures.

Eukaryotes include both simple and complex organisms. Their reproduction could be either sexual or asexual. The sexual reproduction is present only among the eukaryotes, and that involves the important step of meiosis in cell division. By that means the sexual reproduction has allowed the gene exchange to create new traits as adaptations for the changing world. However, the diversity of eukaryotic organisms is very low; e.g. in the human body, there are ten times more prokaryotes than body cells.

What is Prokaryotic?

“Pro” means before, and “karyone” means a case in Greek, giving rise to the term prokaryote. The best example to introduce the prokaryotes is the bacteria. Prokaryotic organisms are more often unicellular and very rarely multi-cellular. Prokaryotes do not have a nucleus. Also, they do not have organelles bound with membranes. However, they have 70S small ribosomes in the cytoplasm. They have a nucleoid with strands of irregular DNA complex in the cytoplasm. There is only one loop of chromosomal DNA in the nucleoid. However, they have a primitive cytoskeleton for the maintenance of the shape of the cell.

The surface-area-to-volume ratio is very high in prokaryotes that results in a high metabolic rate, which leads to an increased growth rate. Therefore, the generation time of prokaryotes is very short. They can form aggregate communities, called colonies that suggest social bonding among prokaryotic organisms. Biofilms are prime examples of their social living, and scientists believe that antibiotic resistance is higher in biofilms.

Figure 02: Prokaryotes

Moreover, prokaryotic shapes are mainly of four known as Coccus, Bacillus, Spirocheate, and Vibrio. They reproduce via asexual means such as binary fission and budding. However, gene exchange takes place through bacterial conjugation. People could never stop studying the prokaryotes, as it is almost impossible to measure the diversity at any scale.

What are the Similarities Between Eukaryotic and Prokaryotic?

• Eukaryotic and prokaryotic organisms are living organisms.
• They are composed of cells.
• Also, both reproduce, grow and die.
• Besides, both carry out many different metabolic processes.

What is the Difference Between Eukaryotic and Prokaryotic?

Eukaryotic cells possess a nucleus and membrane-bound organelles while prokaryotic cells do not contain both nucleus and membrane-bound organelles. We can consider this as the key difference between eukaryotic and prokaryotic organisms. Furthermore, another difference between eukaryotic and prokaryotic organisms is that the eukaryotes can be either unicellular or multicellular while all prokaryotes are unicellular.

Moreover, eukaryotes contain 80S ribosomes while prokaryotes contain 70S ribosomes. Hence, it is another difference between eukaryotic and prokaryotic. Also, a further difference between eukaryotic and prokaryotic organisms is that the eukaryotes contain many chromosomes while the prokaryotes have a single chromosome.

Below infographic on the difference between eukaryotic and prokaryotic shows more differences between both organisms.

Summary – Eukaryotic vs Prokaryotic

Living organisms can be either prokaryotes or eukaryotes. Prokaryotes are simple and tiny organisms while eukaryotes are large, complex organisms. The key difference between eukaryotic and prokaryotic organisms is the presence and absence of a nucleus in their cells. Eukaryotes have a true membrane-bound nucleus while prokaryotic lack a nucleus. Furthermore, eukaryotes have membrane-bound organelles while prokaryotes lack membrane-bound organelles. Also, eukaryotes have 80S ribosomes while prokaryotes have 70S ribosomes. Thus, this is the summary of the difference between eukaryotic and prokaryotic organisms.

List Of Differences Between Eukaryotes And Prokaryotes

Reference:

1. “Prokaryotic Cells.” Khan Academy, Khan Academy. Available here

Image Courtesy:

1.”11820433176″ by AJC1(CC BY-SA 2.0)via Flickr
2.”Prokaryote cell” By Ali Zifan – Own work (CC BY-SA 4.0) via Commons Wikimedia

The three-domain system is a biological classification introduced by Carl Woeseet al. in 1977^[1][2] that divides cellular life forms into archaea, bacteria, and eukaryotedomains. In particular, it emphasizes the separation of prokaryotes into two groups, originally called Eubacteria (now Bacteria) and Archaebacteria (now Archaea). Woese argued that, on the basis of differences in 16S rRNAgenes, these two groups and the eukaryotes each arose separately from an ancestor with poorly developed genetic machinery, often called a progenote. To reflect these primary lines of descent, he treated each as a domain, divided into several different kingdoms. Woese initially used the term 'kingdom' to refer to the three primary phylogenic groupings, and this nomenclature was widely used until the term 'domain' was adopted in 1990.^[2]

Parts of the three-domain theory have been challenged by scientists such as Radhey Gupta, who argues that the primary division within prokaryotes should be between those surrounded by a single membrane, and those with two membranes.^{[citation needed]}

• 1Classification

Classification[edit]

The three-domain system adds a level of classification (the domains) 'above' the kingdoms present in the previously used five- or six-kingdom systems. This classification system recognizes the fundamental divide between the two prokaryotic groups, insofar as Archaea appear to be more closely related to Eukaryotes than they are to other prokaryotes – bacteria-like organisms with no cell nucleus. The current system sorts the previously known kingdoms into these three domains: Archaea, Bacteria, and Eukarya.

Domain Archaea[edit]

The Archaea are prokaryotic, with no nuclear membrane, distinct biochemistry, and RNA markers from bacteria. The Archaeans possess unique, ancient evolutionary history for which they are considered some of the oldest species of organisms on Earth, most notably their diverse, exotic metabolisms, which allow them to feed on inorganic matter. Originally classified as exotic bacteria, and then reclassified as archaebacteria, the only easy way to distinguish them on sight from 'true' bacteria is by the extreme, harsh environments in which they notoriously thrive.

Some examples of archaeal organisms are:

• methanogens – which produce the gas methane,
• halophiles – which live in very salty water, and
• thermoacidophiles – which thrive in acidic high temperature water.

Domain Bacteria[edit]

The Bacteria are also prokaryotic; their domain consists of cells with bacterial rRNA, no nuclear membrane, and whose membranes possess primarily diacyl glycerol diester lipids. Traditionally classified as bacteria, many thrive in the same environments favored by humans, and were the first prokaryotes discovered; they were briefly called the Eubacteria or 'true' bacteria when the Archaea were first recognized as a distinct clade.

Most known pathogenic prokaryotic organisms belong to bacteria (see ^[3] for exceptions). For that reason, and because the Archaea are typically difficult to grow in laboratories, Bacteria are currently studied more extensively than Archaea.

Some examples of bacteria include:

• Cyanobacteria – photosynthesizing bacteria that are related to the chloroplasts of eukaryotic plants and algae,
• Spirochaetes – Gram-negative bacteria that include those causing syphilis and Lyme disease, and
• Actinobacteria – Gram-positive bacteria including Bifidobacterium animalis which is present in the human large intestine.

Domain Eukarya[edit]

Eukarya are uniquely organisms whose cells contain a membrane-bound nucleus (eukaryotes, eukaryotic). They include many large single-celled organisms and all known non-microscopic organisms. A partial list of eukaryotic organisms includes:

Kingdom Fungi or fungi

• Saccharomycotina – includes true yeasts
• Basidiomycota – includes mushrooms

Kingdom Plantae or plants

• Bryophyta – mosses
• Magnoliophyta – flowering plants

Kingdom Animalia or animals

• Arthropoda – includes insects, arachnids, and crustaceans
• Chordata – includes vertebrates as a subphylum

Niches[edit]

Each of the three cell types tends to fit into recurring specialties or roles. Bacteria tend to be the most prolific reproducers, at least in moderate environments. Archaeans tend to adapt quickly to extreme environments, such as high temperatures, high acids, high sulfur, etc. This includes adapting to use a wide variety of food sources. Eukaryotes are the most flexible with regard to forming cooperative colonies, such as in multi-cellular organisms, including humans. In fact, the structure of a Eukaryote is likely to have derived from a joining of different cell types, forming organelles.

Parakaryon myojinensis (incertae sedis) is a single-celled organism known by a unique example. 'This organism appears to be a life form distinct from prokaryotes and eukaryotes',^[4] with features of both.

Alternatives[edit]

Parts of the three-domain theory have been challenged by scientists including Ernst Mayr, Thomas Cavalier-Smith, and Radhey S. Gupta.^[5][6][7] In particular, Gupta argues that the primary division within prokaryotes should be among those surrounded by a single membrane (monoderm), including gram-positive bacteria and archaebacteria, and those with an inner and outer cell membrane (diderm), including gram-negative bacteria. He claims that sequences of features and phylogenies from some highly conserved proteins are inconsistent with the three-domain theory, and that it should be abandoned despite its widespread acceptance.

Difference Prokaryotic Cell Eukaryotic Cell

Recent work has proposed that Eukarya may have actually branched off from the domain Archaea. According to Spang et al. Lokiarchaeota forms a monophyletic group with eukaryotes in phylogenomic analyses. The associated genomes also encode an expanded repertoire of eukaryotic signature proteins that are suggestive of sophisticated membrane remodelling capabilities.^[8] This work suggests a two-domain system as opposed to the near universally adopted three-domain system. Dvdfab keygen 8.2.1.3.

See also[edit]

• Protista - the kingdom which is unclassified in three-domain system

References[edit]

1. ^Woese CR, Fox GE (November 1977). 'Phylogenetic structure of the prokaryotic domain: the primary kingdoms'. Proceedings of the National Academy of Sciences of the United States of America. 74 (11): 5088–90. Bibcode:1977PNAS..74.5088W. doi:10.1073/pnas.74.11.5088. PMC432104. PMID270744.
2. ^ ^abWoese CR, Kandler O, Wheelis ML (June 1990). 'Towards a natural system of organisms: proposal for the domains Archaea, Bacteria, and Eucarya'. Proceedings of the National Academy of Sciences of the United States of America. 87 (12): 4576–9. Bibcode:1990PNAS..87.4576W. doi:10.1073/pnas.87.12.4576. PMC54159. PMID2112744.
3. ^Eckburg, Paul B.; Lepp, Paul W.; Relman, David A. (2003). 'Archaea and their potential role in human disease'. Infection and Immunity. 71 (2): 591–596. doi:10.1128/IAI.71.2.591-596.2003. PMC145348. PMID12540534.
4. ^Yamaguchi M, Mori Y, Kozuka Y, Okada H, Uematsu K, Tame A, Furukawa H, Maruyama T, Worman CO, Yokoyama K (2012). 'Prokaryote or eukaryote? A unique microorganism from the deep sea'. Journal of Electron Microscopy. 61 (6): 423–31. doi:10.1093/jmicro/dfs062. PMID23024290.
5. ^Gupta, Radhey S. (1998). 'Life's Third Domain (Archaea): An Established Fact or an Endangered Paradigm?: A New Proposal for Classification of Organisms Based on Protein Sequences and Cell Structure'. Theoretical Population Biology. 54 (2): 91–104. doi:10.1006/tpbi.1998.1376. PMID9733652.
6. ^Mayr, E. (1998). 'Two empires or three?'. Proc. Natl. Acad. Sci. USA. 95: 9720–9723. Bibcode:1998PNAS..95.9720M. doi:10.1073/pnas.95.17.9720. PMC33883. PMID9707542.
7. ^Cavalier-Smith, Thomas (2002). 'The neomuran origin of archaebacteria, the negibacterial root of the universal tree and bacterial megaclassification'. Int J Syst Evol Microbiol. 52 (1): 7–76. doi:10.1099/00207713-52-1-7. PMID11837318.
8. ^Spang, Anja (2015). 'Complex archaea that bridge the gap between prokaryotes and eukaryotes'. Nature. 521: 173–179. Bibcode:2015Natur.521.173S. doi:10.1038/nature14447. PMC4444528. PMID25945739.