1. Compare and contrast prokaryotic and eukaryotic cells. Be sure to address cell structure, replication (including DNA replication) and gene expression.
The cell structure of prokaryotic organisms is small, only about 1-10 microns in length, and they are also single celled. Prokaryotes contain circular DNA which is held in the nucleoid because they lack a nucleus. The specific organisms that have circular DNA are: mitochondrial, bacterial (eubacteria), and Archaea (Methanobacteria, Halobacteria, and sulfobacteria). Prokaryotes have no membrane-bound organelles because they have no organelles. Their ribosomal subunits are 50S and 30S which come to equal 70S, and their plasma membrane does not contain sterols. In prokaryotes, there is one large vacuole per cell which takes up 50-90% of cell and serves as a reservoir for water; this helps hold turgor pressure in plants. Prokaryotes also cannot go through endo- or exocytosis, and their cell wall is made of peptidoglycan. The replication properties of prokaryotes includes Theta Mode Replication, in which there is only a single origin of replication, but two replication forks. The Okazaki Frangments are 1000-2000 base pairs in length, and the formation of the cell plate is done by the phragmosome. Proteins and RNA help the DNA to fold proteins because prokaryotes do not have histones. Transcription and translation occur simultaneously because prokaryotes have no plasma membrane, therefore no posttranscriptional modifications
Draw a prokaryotic and a eukaryotic cell and list 3 differences between prokaryotes and eukaryotes. Be creative in drawing, but be detailed! (1.5 point)
Well prokaryote is the name given to organisms that are made up from cells that lack a cell nucleus or cells that lack any membrane-encased organelles (a specialized subunit within a cell). In lamens terms, in prokaryotes, the DNA is not bound or held together inside a nucleus. Prokaryotes also only have a single loop DNA. Last but not least prokaryotes are divided into groups or domains but more about that in a minute.
5. Both prokaryotic cell division and eukaryotic cell division replicate their DNA and use the process of cytokinesis.
Eukaryotes and bacteria cells both have the common cell structure of flagella. Flagella is considered a protein. The purpose of the flagella is to help the cell move. Eukaryotes have a different movement type than bacteria. Eukaryotes move in form of an s-shape. Bacterial cells move like helicopter blades (rotor type movement). The flagellum of the bacterial cell are a lot thinner the eukaryote due to the size of the cell.
“Eukaryotic cells are complex and include all animal and plant cells. Prokaryotic cells are smaller and simpler, e.g. Bacteria” - (AQA 2008)
Now that we understand the properties of life and the composition of cells, we can focus on the architecture or formation in terms of basic anatomy and physiology as our second area of exploration. The two types of cells (prokaryotic and eukaryotic) defined before have a few common things such as Plasma membrane (similar to animal cells); Cell wall (similar to plant cells); and Ribosomes, the
Of course, prokaryotic reproduction is limited because cells eventually exhaust their nutrient supply, accumulate metabolic wastes, or are consumed by other organisms. Eukaryotic cells are typically much larger than those of prokaryotes. They have a variety of internal membranes and structures, called organelles, and a cytoskeleton composed of microtubules, microfilaments, and intermediate filaments, which play an important role in defining the cell's organization and shape. Eukaryotic DNA is divided into several linear bundles called chromosomes, which are separated by a microtubular spindle during nuclear division. Nuclear division is often coordinated with cell division. This generally takes place by mitosis, a process that allows each daughter nucleus to receive one copy of each chromosome. In most eukaryotes, there is also a process of sexual reproduction, typically involving an alternation between haploid generations, wherein only one copy of each chromosome is present, and diploid generations, wherein two are present, occurring through nuclear fusion (syngamy) and meiosis. Eukaryotes have a smaller surface area to volume ratio than prokaryotes, and thus have lower metabolic rates and longer generation times.
On the planet, Earth, prokaryotic and eukaryotic are the two major types of cells. Prokaryotic cells are defined as cells with genetic material and cell chemicals all enclosed within a cell wall, and having no defined organelles or nucleus (except ribosomes). Organisms in this group are small in size and mainly consist of bacteria. Eukaryotic cells, however, are defined as having a ‘’true’’ nucleus, membrane-bound organelles, and chromosomes. The nucleus of eukaryotic cells houses the deoxyribonucleic acid (DNA) and directs the synthesis of proteins and ribosomes. Prokaryotic cells, however, are much older cells as these cells are quite ancient and were the only form on planet Earth for billions of years, soon giving birth to eukaryotic cells 1.5 billion years ago.
Eukaryotes consist of cells that the genetic material is DNA in the form of chromosomes is contained within a distinct nucleus. Additionally, besides the eubacteria and archaea, Eukaryotes include all living organisms, which are not the case with prokaryotes that are microscopic single-celled organisms. Prokaryotes do not have a distinct nucleus with a membrane nor other specialized organelles, including the bacteria and cyanobacteria. So a fundamental difference here is that prokaryotes cells do not have organelles, nucleus, but a small amount of DNA in the form of a single, circular chromosome while eukaryotes cells have multiple organelles, a nucleus, as well as sufficient DNA that is organized in multiple, linear chromosomes (Bruck, 2017; OpenStax College, & Rice University, 2013). Another apparent difference in DNA replication between eukaryotes and prokaryotes is that while DNA replication process in eukaryotes takes place inside the nucleus, the DNA replication process in prokaryotes occurs inside the cytoplasm.
Both of them are composed of cells, which are surrounded by a cell membrane and cytoplasm. Both have flagella. Prokaryotes have protein building blocks, while Eukaryotes has multiple microtubules. Both have cell wall. On Prokaryotes it includes peptidoglycan and is chemically complex while in eukaryotes it is chemically simple. The DNA in prokaryotes exists in a space called nucleoid and it is circular DNA while eukaryotes have linear DNA and it is organized into a higher-order structure. Both have ribosomes that are used for translation of RNA into proteins. Both of them can perform transport, DNA replication, transcription, translation, and movement. Although, they have similarities, most are carried out within organelles in eukaryotes.
In the replication process of DNA, there are similarities between the process of replication of a Eukaryote cell and Prokaryote cell. There are also differences in both processes. The most notable difference would have to start with the cell themselves, which may add to additional differences in the processes. A prokaryote is a more simplistic cell with less DNA and a Eukaryote cell is much more complex with vast amounts of DNA.
Their structural similarities are the reasoning behind why one might say that they belong to the prokaryotic domain, being structurally very similar, especially on the first glance. The unique properties will be discussed further later in this essay. SIMILARITIES BETWEEN EUKARYOTES AND ARCHAEA Though structurally, prokaryotic cells seem more similar to archaea than eukaryotic cells, yet when one inspects their DNA, similarities between DNA replication, transcription and translation appear. The DNA polymerase in archaea and eukaryotes are not related to any prokaryotic DNA polymerase, suggesting that these two are of common origin. Other components used in DNA replication are similarly only shared between eukaryotes and archaea (y).
3. Tortora GJ. Functional Anatomy of Prokaryotic and Eukaryotic Cells. In: Microbiology an Introduction. 9th ed. San Francisco, CA: Pearson Education, Inc; 2007: 77-113.
A Prokaryotic Cell are cells without a membrane-bound nucleus. An example of a prokaryotic cell is bacteria.
Primarily, the Archaea were once believed to be just another rare group of bacteria, because like bacteria, they are single-celled microscopic prokaryotic organisms with no membrane bound nucleus (http://www.fossilmuseum.net/Evolution/archaeaevolution.htm). Despite the similarities in the cell structure of Eubacteria and Achaea, molecular research by Dr Carl Woese and his co-workers indicated that they differ significantly on the molecular level (Bacteria in Biology, Biotechnology and medicine, Paul singleton). In this essay, am going to discuss the differences and similarities in the fundamental cellular feature of both organisms.