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Using the structural and functional features of bacteria, describe how a bacterial cell exhibits the characteristics of eukaryotic organisms
Bacteria are important group of organisms in the ecology of living organisms. They are unicellular organisms that have a prokaryotic cellular organization; bacteria are categorized under separate kingdom known as kingdom monera. Bacterial cells are relatively simple, but they can be categorized based on cell shape, there are three basic forms rods, cocci and spiral. When considering about the structure of bacteria it consist of highly complex cell wall and other organelles that are not membrane bound. (Losos, Mason and Singer, 2010, P. 03).
Living characteristics are the evidences to prove something that exist in this world is alive. We cannot prove the living or non-living nature of organisms by just a movement , to prove living nature we can come up with series of seven characteristics shared by living systems , those are cellular organization, order and organization ,sensitivity, growth, development and reproduction, energy utilization, irritability and co-ordination and evolutionary adaptations, those factors are the internal factors that proves living nature. (Losos, Mason and Singer, 2010, P. 04). External or visible living characteristics are size, form and distribution. The first character cellular organization can be discussed under a hierarchal organization that is starting from Atom Molecule Macromolecules Organelles Cells Tissues Organ Organ system Organism, At cellular level atoms are joined together to form molecules, complex biological molecules join together to form structures called organelles, within the membrane bound structures known as cells. Bacteria also single celled and they show atom to cellular level within the hierarchal organization (Koch, 2007). Bacteria consist of unorganized circular DNA that work as a self-replicating genetic material, that has DNA or RNA as genetic material. Even though it is unorganized it contains genetic information that is needed to operate the bacteria as a single unit and involves in replication and gene expression. And also bacterial cell consist of plasmids which are also a form of genetic information storage that helps to determine the production of virulence factors or their resistance to antimicrobial agents, this is the place where living character heredity and evolution expressed (Krisop, 1991). Bacteria do reproduce like other living cells by the mechanism of binary fission, in binary fission bacterial cell grow as twice than its initial size and divides in to two identical cells their method of reproduction is asexual. Like other living cells bacteria also show some adaptations for their competition for existence, the genetic matterial, outer layer and other internal structures associated with bacteria having the ability of alteration, resistance to antibiotics is an important adaptation e.g.: Staphylococcus aureus is resistance to Penicillin. Bacteria also adapt with respect to the environmental changes like concentration of ions and temperature eg: Vibrio parahaemolyticus (Brige, 2000). Bacteria also move by means of appendages known as flagella and cilia. Flagella are long structures protruding from the surface of the cell. Bacteria move by rotating the flagella to reach their destination e.g.: Salmonella (Hollar, 2012) genetic information transfer of bacteria occurs by means of conjugation which is a cell to cell contact, more similar to the sexual reproduction conjugation also makes new genetic combinations, in conjugation genes transfer laterally. This factor explains about the irritability and co-ordination (Clewell, 1993). Bacterial cells respire by means of infoldings of their cell membrane known as mesosomes , they involves in cellular respiration to provide energy needed by the bacterial cell (Hollar, 2012).
- Explain the process of subcellular protein localization. Using two examples describe how protein misocalization causes various human diseases.
Eukaryotic cells produce about 10,000 wide varieties of proteins where they all have final destination of pre-determined target organelles. Protein function maximally in a specific sub cellular localization, it is crucial the correct transport of protein to its final destination for their function. Subcellular localization is key functional characteristic of proteins. Protein mislocalization mechanism needed specifically for analysis of large scale genome sequences, to identify vaccine targets and drug discovery (Chalfie and Kain, 2005). The processes of protein localization are done within the organelles which are also known as compartments (Organelles covered by two membranes). There are three types of translocation mechanisms taken place when transportation of proteins happen, those are gated transportation, trans membrane transportation and vesicular transportartion.in gated transportation synthesized proteins transport between cytosol and nucleus. Here the gate of transportation is nuclear pore. As proteins are larger molecules, without using energy they cannot pass through these pores, therefore to transport histone proteins nuclear localization signals are used , those are signal patch and signal sequence (Neupert and Lill, 1992). Trans membrane transportation is takes place between cytosol and mitochondria, at here proteins are transport through trans locator to the inter membrane, at this process protein should have to unfold, but after going to the mitochondria it will refold. At this refolding process a special protein chaperious help, this is the basic mechanism in mitochondria as well as chloroplast. Finally the vesicular transportation is takes place between organelles and plasma membrane, for this special structure using are vesicles. In all these transport mechanisms signal sequence and signal patch are participate in signaling the exchange of proteins (Scott et al, 2005).
Protein localization plays an important role in maintaining normal cellular functions, any disturbance to this highly regulated transport system can result in disease ranging from metabolic disorders to cancer. From various studies it has proved that protein mislocalization involved in cell cycle regulation and tumor suppression can lead to cancer ((Scott et al,2005). Human breast cancer is one example for protein mislocalization disorders, breast cancer cells most commonly exhibits law P27 protein expression (P27 protein is damaged in most of human tumors, including breast cancers, through accelerated proteolysis) or mislocalization of protein to cystole.in about 41% of primary breast cancers P27 cytoplasmic mislocalization can be noticed (Tot, 2010).
Acute Myeloid Leukemia (AML) is also an example for protein mislocalization disorder.NPM1 gene can be introduced as most important muted gene in AML. NPM1 gene involves in process like DNA rapier, duplication of chromosomes and response to stress. Mislocalization of the protein P227Kip1 from cytoplasm to the nucleus can be observed in acute phase myeloid leukemia (Klosterman, 2006).
- With respect to the role of glucose transporters, discuss the reason for elevated urine and blood glucose levels of patients having diabetes mellitus.
Glucose transporters are a type of proteins that can be found in the membranes that allow glucose to transport through the plasma membrane. This process can take place either actively or passively. There are specific proteins known as GLUT proteins (Glucose Transporter Proteins), which are uniports which facilitates in diffusion. There are five types of GLUT protein. GLUT 1 protein involves in regulation of glucose level in urine whereas GLUT4 protein involves in regulation of glucose level of blood, GLUT 4 protein can be found in places where active transportation and passive transportation of glucose takes place (Bittar and Bittar, 1996)
Diabetic mellitus is a metabolic disease which leads to hyperglycemia; hyperglycemia condition is due to proteins in secretion of insulin. There are 2 types of diabetic mellitus conditions as type 1 and type 2. Type 1 diabetic mellitus is due to successive destruction of beta cells in pancreas, leading to insulin deficiency, type 1 is a insulin dependent condition. Whenever insulin go and bind with insulin receptor it starts signaling that makes GLUT4 to translocate glucose towards plasma membrane. This combination of GLUT 4 with plasma membrane increase the amount of GLUT4 proteins in cell, from that process elevates the glucose transportation into the cell. Among diabetic patients about 15% patients have type 1 diabetic mellitus condition (Thomas and Guiterrez, 2005). Type 2 diabetic mellitus is usually caused at the latter part of the life (after age of 30). Type 2 diabetic mellitus condition caused due to uneven secretion of insulin and insulin resistance, abundant GLUT 4 protein level can be seen in type 2 diabetic mellitus, 74% GLUT1 expression has found in urine of patients with type 2 diabetes. Patients with type 2 diabetes show long term symptoms than type 1 patients. About 85% of diabetic patients have type 2 diabetic mellitus condition (Rios and Fuentes, 2009).
Explain how meiosis facilitates the evolution of organisms
Meiosis is a special type of cell division that takes place only in the germ cells to produce gametes. Meiosis also introduce as reduction division where gametes are produced with half the number of parental chromosome number. And also exchange of genetic material between homologous chromosomes takes place.to maintain the chromosome number in a species this reduction division very important (Rieder, 1998). Meiosis is occurs in two stages as meiosis 1 and meiosis 2. In meiosis 1 there are 4 stages as prophase 1, metaphase 1, anaphase 1 and telophase 1. During prophase 1 nuclear membrane starts to disappear and spindle starts to form and condensation of DNA takes place due to that chromosomes become visible. At metaphase 1 lining up of chromosomes at equator takes place and spindles are completely formed. During anaphase 1 tetrads pull apart and chromosomes with two chromatids move towards opposite poles, at telophase 1 condensation of chromosomes happen and reformation of nuclear envelop occure, cytokinesis then fallows resulting two cells having half the original number of chromosomes. Then second meiotic division or meiosis II occurs. Sole reason to undergo second meiotic division is to reduce the amount of DNA, therefore meiosis II has the same procedure as mitosis, after second meiotic division four new daughter cells are all haploid consisting with right amount of DNA and they are ready to develop in to sperms and eggs at the stage of telophase II (Handel, 1997). There are some significant events that takes place in meiosis which are important in genetic variation, those are crossing over, independent assortment and formation of synapse. Crossing over is exchange of DNA chromatids between non sister chromatids. Crossing over between sister chromatids is not happening in meiosis. Independent assortment is the random alignment of chromosomes in daughter cells during anaphase 1.synapse is side by side alignment of homologous chromosomes at prophase 1. These three events are the key factors for the genetic variation took place in sexual reproduction (Cregan, 2007).
The genetic variation caused by meiosis is the key factor for evolution. the most significant event of evolution which is the idea of natural selection put foreword by English naturalist Charles Robert Darwin(1809-1882). In Darwin’s theory of evolution how living organisms on earth have changed over time and achieved diversity of new forms is described, the most proved statistics shows that any human is differs on average of 1 to 10,000 DNA base pairs(Losos, Mason and Singer 2010, P. 08). In independent assortment random separation of chromosomes towards opposite taking place and that random separation will result in various combination of chromosomes, these different combinations leads to increased genetic variation among living organisms. During crossing over the exchange of genetic material between homologous chromosomes and their rejoining leading to a unique combination of chromosomes, these events plays a major role in facilitating genetic variation, ad that genetic variation is the key mechanism for evolution (Stikeberger, 2005).
Discuss the role of apoptosis induction in cancer therapies
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