Cristina Alzandua General Biology 1401 Dr. Erin Schuenzel February 13, 2014 Bacterial and Eukaryotic Cell Structures All organisms are composed of cells which are characteristically microscope in size. Cell size is limited by the efficiency of diffusion across the plasma membrane. A typical eukaryotic cell is 10 to 100 micrometers in diameter opposed to prokaryotic cells are 1 to 10 micrometers in diameter. Bacterial and Eukaryotic cells display different cell organization in their size and structure, but despite this all they display basic structural similarities as well. Differences between the structures of a bacterial and eukaryotic cell Bacteria cells are sheathed by a strong cell wall which is composed of peptidoglycan (polymer of sugar).
Most prokaryotes and some eukaryotes (plants and fungi) have a cell wall; a strong structure surrounding the cell and preventing it from bursting in a hypotonic environment. However, the cell walls of prokaryotes and eukaryotes, although similar in function, are made of different types of materials. Both prokaryotes and eukaryotes have a fluid-like matrix that fills the cell called cytoplasm. Both organisms have a supportive cytoskeleton within the cell, although this feature was only recently discovered to occur within prokaryotes. Both prokaryotic and eukaryotic cells can have thin extensions of the plasma membrane supported by elements of the cytoskeleton, including flagella and cilia in eukaryotes and flagella, end flagella, fimbriae and pili in prokaryotes.
Prokaryotic cells are found in organisms such as bacteria, most commonly eubacteria and archae bacteria. Eukaryotic cells are therefore are found in all other living organisms, the name implying that there is a proper nucleus present. As there is no nucleus present in prokaryotic cells the DNA helix is a single coiled chromosome that is unsupported and so can float freely around the cell, however in a eukaryotic cell the DNA helix is made up of linear chromosomes supported by the histone protein. In Eukaryotic cells there is also a distinct nuclear membrane Prokaryotic cells are smaller than Eukaryotic cells, according to “Pharmaceutical Microbiology†the majority of bacteria fall within the general dimensions of 0.75 to 4mm compared to the size of common eukaryotic cells which can be up to 40 times larger than Prokaryotic cells and measure between 50 and 150mm. Prokaryotic cells and Eukaryotic cells both can contain a cell wall however in prokaryotic cells the cell wall is peptidoglycan (a mixture of sugar and protein) if the organism is a eubacteria, or pseudomurein if the organism is a archae bacteria whereas in eukarotic cells a cell wall is only present if the organism is a plant or a fungi and the cell wall is constructed of cellulose in plants or chitin if the organism is a fungi.
A few of the most noticeable similarities include both having cytoplasm, a plasma membrane, DNA and ribosome’s. Most eukaryotes and prokaryotes also have a cell wall, otherwise known as a structure outside the cell membrane. In addition, the genetic code in a eukaryote and prokaryote are exactly the same. Inside the cytoplasm of a eukaryote is much different than a prokaryote. For instance,
Animal cells have a cell membrane allowing them flexibility to change structure into all types of organs and then turn into systems in plant cells they are slightly different as they have a cell wall giving it a more solid structure. Plants don’t need to move around! Mostly multi cellular, eukaryotic cells differ a lot from the prokaryotic cells (bacteria) which are unicellular and don't have a nucleus or any membrane bound organelles smaller in size the prokaryotic cell 0.1-10 µm compared to the eukaryotic cell which is 10 - 100µm In order for cells to survive they need an energy source Autotrophs (plant cells, virus cells) acquire there energy from light or chemical energy from their physical environment. Heterotrophs (animals, bacterial, fungal cells) gain their energy from other living organisms or there dead remains this phenomenon is known as metabolism these types of organisms are usually more complex. http://www.phschool.com/science/biology_place/biocoach/cells/common.html http://www.med.nus.edu.sg/ant/histonet/txt/tacsem/tac22.sem.html The liver detoxifies and removes harmful substances from the blood this electron micrograph shows us a Hepatocyte cell this predominant cell type in the liver performs most of the livers functions; metabolism, storage , secretion and bile production they absorb nutrients
All viruses have genes made from either DNA or RNA, long molecules that carry genetic information; all have a protein coat that protects these genes; and some have an envelope of fat that surrounds them when they are outside a cell. Fungi are diverse in terms of their shape, size & means of infecting humans. Fungi are eukaryotes, meaning that like parasites, their cells have a true nucleus and complex internal structures. They are most commonly found as environmentally resistant spores and molds, but can cause disease in humans in the forms of yeasts. Parasites are part of a large group of organisms called eukaryotes.
I will also include a labelled diagram of a typical cell. Cells Cells are the basic unit of living materials; every individual is made up of billions of cells. Cells vary in size and shape and carry out different functions, but there are three things that can usually be found in any type of cell; nucleus, cytoplasm and membrane (however, a mature red blood cell for example doesn’t have a nucleus so is therefore an exception from this statement). Cells are usually very small and require microscopes for them to be seen. There is only one cell in the body that can be seen with the naked eye, the female ovum.
Another similarity between the two cells is that they both have smooth and rough endoplasmic reticula inside of them. The job of the smooth and rough endoplasmic reticula’s function is to transport and alters the energy inside of it. In the end the two cells have many similarities between them such as organelles. Though animal and plant cells have many similarities they also have many differences between each other. A large difference is the cell wall, the cell wall is found in the plant cell but not the animal cell.
All viruses have genes made from either DNA or RNA, all have a protein coat that protects these genes; and some have an envelope of fat that surrounds them when they are outside a cell. Fungi: Like plants and animals, fungi are multicellular organisms. One major difference is that fungal cells have cell walls that contain chitin, unlike the cell walls of plants, which contain cellulose.The chitin adds rigidity and structural support to the thin cells of the fungus, and makes fresh mushrooms crisp Most members of the kingdom Fungi lack flagella; the structures are completely absent in all stages of their life Parasites: A parasite is an organism that lives on or inside another organism to the detriment of the host organism. These are of various forms and types.A parasite is an organism that lives on or in a host and gets its
The other major category of living organisms is the Eukaryotes. They are mostly multicellular organisms, unlike prokaryotes, which are mostly unicellular. One difference in cell structure of eukaryotes is the presence of membrane-bound organelles, such as a nucleus. This is where genetic material is stored and organized (www.animals.about.com). Several other organelles exist within a eukaryotic cell, including mitochondria, endoplasmic reticulum, lysosomes, etc.