INTRODUCTION
Chlamydomonas reinhardtii is a unicellular, eukaryotic green algae that is commonly found throughout the world. This photosynthetic organism possesses two flagella that serve as the basis of its motility. Not only is this organism easily accessible, but it is a model organism for many areas of study (Rochaix et al, Silflow and Lefebvre 2001) including photosynthesis, respiration, flagella, circadian rhythm, cell to cell recognition and even heavy metal homeostasis and tolerance (M. Hanikenne). The flagella of C. reinhardtii are easily visible and are remarkably similar to other mammalian microtubule structures (Silflow and Lefebvre 2001). This allows experimental studies to occur that are able to aid in the understanding of human disease related to the dysfunction of microtubule structures within the human body. Since these organisms are capable of sustaining life in absence of their flagella, they become a model organism for studying movement, regeneration and mutational defects. The flagella are easily removed without damaging the cell and make flagellar protein analysis a simpler process. Genetic analysis of mutant strains is easily accessible because of the complete sequencing of its genomes (Lefebvre and Silflow 1999).
Although flagellum does not have a life-sustaining role in this organism, it is still very beneficial throughout its lifecycle. Like all chlorophyll producing plants, C. reinhardtii requires light to support its cellular functions. In order to enhance its ability to receive the ideal quantity, it is able to sense light with an eyespot and use these signals to control the beating of the flagella (Witman GB 1993). C. reinhardtii is able to propel itself forward by the opposite and simultaneous mo...
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Recreating the evolutionary history of dinoflagellates has been challenging as they possess a known ability to transform from noncyst – to cyst – forming strategies (unreferenced/Wikipedia). The dinoflagellate nucleus lacks histones, nucleosomes and maintains continually condensed chromosomes during mitosis (Dodge 1966), making their classification difficult (Hackett et al 2004). Though being classified as eukaryotes, the dinoflagellate nuclei are not characteristically eukaryotic (Dodge 1966). However, typical eukaryotic organelles, such as Golgi bodies, mitochondria and chloroplasts are present in dinoflagellates (Morrill et al 1983). Since dinoflagellate nuclei possess intermediate characteristics between the coiled DNA areas of prokaryotic bacteria and the well-defined eukaryotic nucleus it was termed ‘mesokaryotic’ by Dodge (1966).
Cain, M. L., Urry, L. A., & Reece, J. B. (2010). Campbell Biology. Benjamin Cummings.
The hypothesis for this experiment was that the cell fraction in the cuvette marked P2 will have more chloroplast activity because it will exhibit greater color change and differences in the absorbance readings compared to the other cuvettes when exposed under the condition of light; moreover, this notion was believed to be so because the more a cell fraction is centrifuged, the more intact chloroplasts we’ll find (Leicht and McAllister,
During interphase, the cells in both animals and bacteria carry out their division general functions according to the type of their cells. Unlike in plants, a preprophase group of cytoskeletal proteins emerge at a future location of the cell plate. At prophase stage, duplicated chromosomes compress in a way that can be seen with the help of a microscope. On the other hand, the mitotic spindle is formed at one side of nucleus, whereas in plants, spindle is formed around the nucleus. During prometaphase in animals and bacteria, the nuclear membrane disappears, the chromosomes attach themselves to mictotubules and start to move. In plants, however, the preprophase group dissolves while at metaphase stage, the chromosomes get aligned at the core of the cell. At anaphase, there are fewer differences between animals and plants. The chromosomes shift apart towards the both par...
I’m comparing cilia to a ceiling fan in a house. Cilia are hair –like projections of a cell membrane. The hair-like projections make the cell look furry. The functions of the cilia are to wave in unison to move stuff outside of cell. The cilia increases surface area of a cell and are common in multi cellular organisms. I compared cilia to a fan because they both move stuff. The fan moves air in a house with circular motions. The cilia moves stuff outside the cell with its hair like projections.
Eukaryotic cells share several distinguishing features, such as: cytoplasm within specialized organelles such as the mitochondria, chloroplast, the Golgi complex, both a rough and smooth endoplasmic reticulum, a nuclear envelope that isolates DNA from the cytoplasm, and a endomembrane system that provides structure and function to the organelles of the cell. Both the mitochondrion and chloroplast are energy transducing organelles, meaning that they transform energy from one form to another, and are believed to be evolved from free living prokaryotes as held by the theory of endosymbiosis. This theory suggests that infolding of the plasma membrane coupled with the absorption of a prokaryotic cells by other prokaryotes could evolve into a later, more complex and specialized type of cell and is proofed by related morphological features such as between cytobacteria and chloroplasts, and between mitochondria and aerobic prokaryotes. Further substantiation includes mitochondria and chloroplasts reproduction through binary fission like prokaryotes, the presence of DNA in both free living prokaryotes and in energy transducing organelles (apart from in the nucleus), protein synthesis and the presence of enzymes and ribosomes where the ribosomes of prokaryotes are comparable to those in mitochondria and chloroplast,
In short, Mr. Euglena will survive the tough situation of a crowded area by waiting for the sun to rise higher in the sky. By waiting, his chloroplasts will absorb sunlight allowing photosynthesis to occur. When photosynthesis produces a glucose molecule, the glucose molecule is transferred to the cristae for the process of aerobic respiration. Aerobic respiration then makes ATPs which will release energy to the kinetosome. This energy will enable the kinetosome to anchor the flagellum so that it may function to move Mr. Euglena to a less crowded area to live.
Cyanobacteria, also known as Blue-green algae, (Cyanophyta), (Myxophyta) and (Cyanochloronta) are difficult to classify, and there are numerous schools of thought on their Taxonomy. Cyanobacteria are prokaryotic organisms however posess many of the same qualities as algae and therefore were previously categorized as such, hence the name blue-green algae. They form a class greatly dissimilar from that of other algae, and possess many of the same characteristics of bacteria. They produce energy via the process of photosynthesis and posses photosynthetic pigments chlorophyll a, just as plants, and phycobilin which are responsible for the blue-green hue. The main distribution of Cyanobacteria is in aquatic environments such as fresh and saltwater, they are however, found in terrestrial habitats where there is sufficient moisture and can even occur in deserts. Cyanobacteria do not have a nucleus or chloroplasts, they’re DNA and chlorophyll float freely within the cytoplasm. They show a variety of movements, such as gliding, rotation, oscillation, jerking and flicking. In addition they possess gas vesicles, giving them buoyancy in water. Cyanobacteria reproduce exclusively by asexual means via binary fission and may form exo- or endospores as well.
Research of the Arp2/3 complex helps us understand how and why the complex is necessary in cells, specifically for the extension of lamellipodia and fibroblast cell migration in situations such as the healing of wounds. Prior to this article being published, the Arp2/3 complex had already been extensively studied and was known to be a protein made up of seven subunits that is a major player in a cell’s ability to regulate actin cytoskeletons. The idea behind the study discussed in this article is that Arp2/3 will be genetically disrupted to understand its function in fibroblast motility within cells. The hypothesis deduced based on this is that fibroblasts can’t form in lamellipodia without Arp2/3.
The F-actin inhibitor Latrunculin (identified as a toxin in the marine sponge Latrunculia magnifica) (Spector et al., 1983) enhances the rate of depolymerization of the actin network and prevents its polymerization (Yarmola et al., 2000). Jasplakinolide is cell permeable and has been used in live cells to explore the effect of filament disassembly in cell motility, cell adhesion and vesicle transport (Cramer, 1999). Latrunculin has been utilized to investigate the role of the actin cytoskeleton in cell migration, endocytosis and spindle orientation. Since the actin inhibitors cannot distinguish between muscle and cytoskeletal forms of actin, these are less common is clinics due to many undesirable off-target effects caused by the lack of specificity for the different types of actin. Regardless, the actin inhibitors are still useful on a cellular level in research studies to further the understanding of biological
Wilkie, I.C. "Autotomy as a Prelude to Regeneration in Echinoderms." Microscopy Research and Technique 55.6 (2001): 369-96. Print.
Though these morphological changes have been known for some time, very little is known about the mechanisms underlying them. The processes that govern cell cycle regulation are of great interest to researchers, as aberrations like improper chromosome segregation and nonfunctional microtubule assembly can result in apoptosis or, if the cell doesn’t undergo apoptosis, cancer. Most evidence surrounding cell cycle regulation comes from studies on embryonic development of amphibians. Amphibian eggs contain many of the proteins required to carry out mitosis, but can only enter mitosis after fertilization. In addition to these proteins, the eggs contain a v...
In contrast, eukaryotic organisms typically include (but are not limited to) membrane-bound organelles such as the nucleus, mitochondria, endoplasmic reticulum (E.R.), golgi body, lysosome and peroxisome. The main defining difference between a eukaryote and prokaryote is that the latter does not contain a nucleus or any such organelles. Such a definition, however, can be argued to be a poor discriminator between organisms of Eukarya and Prokarya, because it describes only what prokaryotes are lacking, not what they fundamentally are. This essay aims to detail a more comprehensive definition of why these two kingdoms are so different from each other. A key example of this thinking is that, while prokaryotes are often singly responsible for metabolic processes, reproduction and cell repair, eukaryotes are often highly specialised in order to perform certain functions and rely upon other cells to fulfil different functions. For exa...
The cytoskeleton is a highly dynamic intracellular platform constituted by a three-dimensional network of proteins responsible for key cellular roles as structure and shape, cell growth and development, and offering to the cell with "motility" that being the ability of the entire cell to move and for material to be moved within the cell in a regulated fashion (vesicle trafficking)’, (intechopen 2017). The cytoskeleton is made of microtubules, filaments, and fibres - they give the cytoplasm physical support. Michael Kent, (2000) describes the cytoskeleton as the ‘internal framework’, this is because it shapes the cell and provides support to cellular extensions – such as microvilli. In some cells it is used in intracellular transport. Since the shape of the cell is constantly changing, the microtubules will also change, they will readjust and reassemble to fit the needs of the cell.
According to Carl Woese, a professor of microbiology at the University of Illinois, eukaryote cells are more structurally complex than those of their prokaryotic counterparts. Eukaryote evolved from prokaryotic cells as they adapted to their environment. Evidence shows that mitochondria, an organelle found in all eukaryotic cells, are actually the product of two independent bacteria’s becoming one. This process is known as endosymbiosis or teamwork. Some evidence supporting the idea of endosymbiosis follows; the chloroplasts and the mitochondria are similar to bacteria in size as well as structure, both mitochondria and chloroplasts contain limited amounts of genetic material which could be from splitting, and both of these organelles are surrounded by a double membrane which suggest that the out membrane may be derived from the engulfing vesicle, and the inner