Summary Of Prokaryote And Eukaryote

When life arose on Earth about 4 billion years ago, the first types of cells to evolve were prokaryotic cells. For approximately 2 billion years, prokaryotic-type cells were the only form of life on Earth. The oldest known sedimentary rocks found in Greenland are about 3.8 billion years old. The oldest known fossils are prokaryotic cells, 3.5 billion years in age, found in Western Australia and South Africa. The nature of these fossils, and the chemical composition of the rocks in which they are found, indicates that these first cells made use of simple chemical reactions to produce energy for their metabolism and growth. Eukaryotic cells evolved into being between 1.5 and 2 billion years ago. Eukaryotic cells appear to have arisen from prokaryotic cells, specifically out of the archaea. Indeed, there are many similarities in molecular biology of contemporary archaea and eukaryotes. However, the origin of the eukaryotic organelles, specifically chloroplasts and mitochondria, is explained by evolutionary associations between primitive nucleated cells and certain respiratory and photosynthetic bacteria, which led to the development of these organelles and the associated explosion of eukaryotic diversity. Today Prokaryotes

Currently, there are two major competing theories for the endosymbiotic origin of eukaryotic cells. The first theory claims that the eukaryotic cell is a combination of an archaeon with a

Since they do not contain a nucleus they would be in the prokaryotic domain. They would need to be from the kingdoms Bacteria Specifically Eubacteria. They use photosynthesis to produce their own food. This animal is most likely Prochlorococcus. This is the most abundant photosynthetic cell in the ocean. Another one is cyanobacteria or blue green algae, but they are prokaryotic unlike algae. They could be grouped by their shapes like cyanobacteria are spherical, rod, and spiral. They can also be grouped as photosynthetic since they have

7. The theory of endosymbiosis says that mitochondria and plastids used to be small prokaryotes living within larger cells. The prokaryotic ancestors of mitochondria and plastids were bacteria engulfed by a larger cell. Because they both benefited from this situation, the bacteria living inside the cell was passed down from generation to generation. The evidence is that mitochondria reproduce and move independently within the cell.

There are two main types of cells in the world. The simplest cells such as bacteria are known as Prokaryotic cells, and human cells are known as Eukaryotic cells. The main difference between each of these cells is that a eukaryotic cell has a nucleus and a membrane bound section in which the cell holds the main DNA which are building blocks of life.

The purpose of this study is to identify four unknown organisms. The unknown organisms have been assigned randomly to six-research groups by Professor Hoffman. Each research group was provided two eukaryotes and two prokaryotes. The unknown organisms will fall into the following classifications: bacteria, algae, fungi, or protozoans. All living organisms are organized into one of three domains of life, Bacteria, Archaea, and Eukarya.

From what is known so far, Last Universal Common Ancestor (LUCA) lived approximately 3.5 to 3.8 billion years ago4. Carl Woese who originally proposed the three domain system (Bacteria, Archaea, and Eukaryote) which was based on the analysis of rRNA sequences of those three domains said Luca is, “…simpler, more rudimentary entity than the individual ancestors that spawned the three domains and their descendents regarding its genetic machinery4.” In addition, Woese is responsible for dubbing the name ‘Luca.’ Luca is a unicellular (single celled) organism (hypothetical). The real question is: If all of life evolved from a unicellular organism, how would we know

Deep ocean trenches are environments that have historically been shrouded in mystery, their inaccessibility rendering such limited explorations as net dragging and dredging for samples (Lee, 2012). While potential for chemosynthesis had been proposed as long ago as 1890, it was nearly a century later before such systems were demonstrated to be active on the ocean floor (German, 2011). Further investigation has shown that ecosystems are surviving and thriving along the ocean floor within these trenches. Studies have shown that deep ocean trenches contain ecosystems that are biologically and geologically active, producing a high diversity of organisms that must withstand a variety of environmental changes (Anderson et al., 2014). Recent explorations have confirmed new forms of life in deep ocean trenches. Life discovered in such an extreme environment is call for investigation.

Not too long ago, brilliant scientific pioneer, microbiologist and biophysicist Carl Woese presented his groundbreaking find that would revolutionize the scientific world. He and his partners discovered the kingdom consisting of single-celled organisms, which is today referred to Archaea. Thanks to Woese’s discovery, we now classify living organisms in three domains, Archaea, Bacteria, and Eukarya. Before Woese’s breakthrough, we did not realize how common and important Archaea actually are. Woese specialized in working with ribosomal DNA, which is how he uncovered Archaea. Eugene V. Koonin expresses deep admiration and praise towards Woese in his article. However, Koonin repeatedly judges Woese’s analysis on the evolution of cells as inexact and too general for legitimacy.

Per this theory, GpII invaded the eukaryotic lineage in its genesis via the mitochondrial endosymbiosis and have been inserting themselves into coding genes continuously since; a mechanism consistent with the high levels of GpII in some α-proteobacteria (Robart & Zimmerly, 2005) and the ability of yeast mitochondrial GpII to insert themselves into double stranded genomic DNA (Zimmerly et al., 1996). Symbiosis-related selection pressure upon the α-proteobacteria coupled with its bacterial nature of jettisoning unwanted genes caused the exchange of GpII and cognate maturases (Schmitz-Linneweber et al., 2015) between the proto-mitochondrion and the host cell which lacked the necessary control mechanisms to restrict their spread. Hence, the proportion of introns in the LECA genome is considerably greater than in contemporary eukaryotic lineages, excluding some vertebrates (Figure.1). Comparison of nuclear-encoded cytoplasmic ribosomal proteins and mitochondrial ribosomal proteins showed that intron positions were conserved (Yoshihama et al., 2006), suggestive of common descent between all eukaryotes. However, the presence of introns presents significant problems to the host. Principally, random and aggressive insertion of foreign gene elements is likely to disrupt essential coding sequences within the host genome; hence, only neutral intron-insertions could persist. Additionally, splicing reactions require the energetically expensive and complex machinery of the spliceosome, comprised of over 150 proteins and 5 snRNA units (Wahl et al., 2009), any fault in which would cause broad harm to the cell (Chorev & Carmel,

Prokaryotic Cells All living things are made of cells, and cells are the smallest units that can be alive. Life on Earth is classified into five kingdoms, and they each have their own characteristic kind of cell. However the biggest division is between the cells of the prokaryote kingdom (monera, the bacteria) and those of the other four kingdoms (animals, plants, fungi and protoctista), which are all eukaryotic cells. Prokaryotic cells are smaller and simpler than eukaryotic cells, and do not have a nucleus. Prokaryotic means 'pre-nucleus' and eukaryotic means 'true nucleus'.

Some the evidence for this theory include the mitochondria and plastids which can be identified in a eukaryot; however, prokaryotes originally also have the same functional capabilities as the mitochondria, as well as plastids. Perhaps the mitochondria’s development is simply a result of condensing the process of energy creation into a single organelle and the development of plastids was a result of prokaryotes also being capable of completing a similar task; however, felt the need for condensing this task into a single

Prokaryote cells - bacteria and archeans. They are single celled organisms, where the DNA is not separate from the cytoplasm. These prokaryote cells formed the earliest and most primitive life on earth.

Perhaps one of the first lessons one is taught about bacteria is that they constitute the prokaryotic domain of life, while humans and most other readily visible life forms are firmly rooted in the eukaryotic domain. These domains diverged many millions of years ago from a common ancestor and, while the eukaryotic branch later split into eukaryotic and archaeal domains, it maintained its separation from the prokaryotic domain (Woese et al., 1990). Prokaryotic and eukaryotic genomes are naturally very distinct in both content and structure as a result of eons-long separation, and one tends to classify these domains as very distinct entities.

After the unanticipated discovery of a separate mitochondrial genome, there have been new insights into its inheritance and mutation. There is enough evidence to bolster the fact that fusion between a-proteobacteria and archaebacteria is an integral event in evolution of eukaryotic cells. However, it has also been conjectured that eukaryotic cell may have originated from prokaryotes. As a part of this evolution, many mitochondrial ancestral genes were lost. These are the genes that were no longer required in their new host cell environment. All eukaryotes contain genes of mitochondrial origin in their nuclear genome. However, this is only true for a few genes. Studies indicate that humans and mice have only 35% of mitochondrial gene products that are similar to bacteria Rickettsia. Remaining mitochondrial proteins are derived from either non-mitochondrial nuclear genes or as a result of horizontal gene transfer events. Mitochondria have developed different states during the evolution of eukaryotic cell. Aerobic mitochondria retain a small mtDNA while anaerobic mitochondria and hydrogen-producing mitochondria alter the function of respiratory chain and also maintain mtDNA.