This experiment was carried out to characterize an enzyme, -amylase by extracting it from the corn. The factors affecting the enzymatic activity of -amylase such as substrate concentration, temperature, pH, ionic strength and inhibitors were inves
Title: Characterization of an enzyme Introduction: Enzyme is a protein molecule that acts as the biological catalyst of chemical reaction where the substrates are converted into products. With the aids of enzyme, the rate of reaction will be increased since the enzyme provides an alternative pathway for reaction by lowering the activation energy needed (Taylor et al., 1997). An enzyme is a tertiary protein with 3 dimensional structure maintained by ionic bonds, hydrogen bonds, hydrophobic interactions and disulphide bridge (Copeland, 2000). It is highly specific as only one type of substrates can bind and catalyze by one type of enzymes. The substrates will bind to a restricted region which is known as the active site which is formed by amino acids with a framework that configures the active site (Campbell & Reece, 2008). For the lock-and-key hypothesis, only substrates which have shapes that are compatible fit to the shape of the active site can be catalyzed by the enzyme while for the induced-fit mechanism, the active site of the enzyme changed its shape to suit the shape of the substrates since the amino acid that determine the shape of the enzyme can mould into a precise shape (Taylor et al., 1997). When the substrates enter the enzyme's active site, they are held together to form a enzyme-substrate complex by hydrogen bonds and ionic bonds. The active site then lowers
POMC cell function
The Prohormone 'Proopiomelanocortin' (POMC) is involved in several important cell functions. Critically review this statement in terms of its involvement in human pigmentation. A dissertation presented by Rekha Balakrishnan For the BSc (Hons) in Biomedical Sciences In the University of Bradford Division of Biomedical Sciences School of Life Sciences University of Bradford Bradford DATE of SUBMISSION 3rd April 2009 WORD COUNT 4788 TABLE OF CONTENTS Abstract 3 Introduction 4 Cell Functions of POMC 8 POMC Derived Peptides 12 The Importance of POMC- derived Peptide............................................... 15 POMC and Pigmentation 17 POMC and Pathology 20 Conclusion 22 Bibliography 25 Abstract This work reviews several important cellular-based functions of proopiomelanocortin (POMC), with emphasis on human skin pigmentation. As melanocortin peptides, PMOC regulates several physiological functions, including skin pigmentation, adrenal and cardiovascular functions, inflammation, energy homeostasis, and exocrine secretion. It also produces an array of biologically active peptides, by means of an extensive, tissue-specific posttranslational process. The skin is a target organ for the actions of POMC and its derived neuropeptides, including ?-melanocyte stimulating hormone (?-MCH), ß-endorphin, and ACTH. This study also surveys diseases associated with
Water Strss on Plants
Simulated Water Stresses on Early Plant Development Aim Rationale Results Interpreting Conclusion Appendix I - Plan Appendix II - Trial Plan Bibliography Abstract: As evidence for global warming continues to accumulate, various regions of the planet are already succumbing to drought - causing crops to fail and leading to widespread famine. Understanding the limits of a crop's water tolerance, and how minute changes in water concentration in soil can affect plant growth could be useful in predicting the future success of crops which may undergo water stress. Aim: To investigate water
Discuss how changes in control of the cell cycle contribute to cancer development Cancer is a multifarious disease, with a common feature that most tumours harbour one or more genetic mutations that allow them to advance outside their normal growth restr
Discuss how changes in control of the cell cycle contribute to cancer development Cancer is a multifarious disease, with a common feature that most tumours harbour one or more genetic mutations that allow them to advance outside their normal growth restraints. This proliferation is normally harnessed by the control of the cell division cycle, which in turn, is majorly regulated by the cyclin dependent kinases (Cdks) family of serine/threonine kinases and their regulatory partners, the cyclins (Errico, et al., 2009). In this essay, the roles of Cdks, cyclin complexes, regulatory proteins and other cell-cycle regulatory processes will be underlined, followed by an analysis of the genetic lesions in these regulators which may contribute to tumorigenesis. Fundamentally, cancer, or a neoplasm is a disease where cellular proliferation is no longer under normal growth control. The growth of this clone of cells exceeds, and is uncoordinated with that of normal surrounding tissues (NHS, 2009). Ultimately, this deregulation of growth and division of the cancer cells disrupts and interferes with the normal functioning of the body, either at its origin or through spreading to another location, eventually resulting in the potential death of the sufferer if left untreated. Other complex characteristics include the ability of the cancer cells to induce vascularisation of the tumour in
Medico-legal Problems of establishing the Time of Death
Medico-legal Problems of establishing the Time of Death No problem in forensic medicine has been investigated as thoroughly as that of determining the time of death on the basis of post mortem findings. Determining the time of death is of utmost importance but it is extremely difficult and accuracy is impossible. A recurring problem in forensic medicine is the need to fix the time of death within the limits of probability, the longer the interval of time between death and the examination of the body, the wider will be the limits of probability. The longer the post mortem interval, the more likely it is that associated or environmental evidence will furnish more reliable data on which to estimate the time of death than will anatomical changes. The post mortem interval (the time elapsed from death until discovery and medical examination of the body) may be preceded by a significant survival period (the time from injury or onset of the terminal illness to death). The survival interval is best established by evaluating the types, severity and number of injuries present and the deceased's response to them, taking into account pre-existing natural disease. At autopsy it is necessary to assess the evolution of the inflammatory response and repair process in skin and viscera. Three Sources of Evidence for estimating the time of death: . Corporal evidence; that present in the
Two-component signalling pathways in bacteria
Er Chian Kong 41004159 CMBS 309 Advanced Biochemistry Essay Two-component signalling pathways in bacteria Experiencing "life on the edge", bacteria have to respond to changes in the environment in order to survive. Facing limited resources and coupled with intense competition in almost every environment, bacteria have to accommodate any potential energy sources of nitrogen, carbon while resisting toxicity to their regulatory process and metabolism. By establishing an intra and inter species communication, bacteria can sense the multitude of extracellular signals and responds to enhance chances of survival. Bacteria change their physiological behaviour according to signals detected in their environment, typically reflected in gene expression alteration. The two-component system (TCS) is predominantly involved in many signal transduction pathways in many prokaryotes, slime molds, fungi and even plants. [1] It is a major signalling mechanism that mediates the response to various environmental stimuli in bacteria and is based on a "sensor" and "regulator" relationship. The biochemical event of the two-component signal transduction was first described by Ninfa and Magasanik [2] in 1986. Ninfa and Magasanik described in Nitrogen Regulatory (NR) protein system, which regulate gene expression in response to the available of nitrogen source in Escherichia coli. Similarities
Describe the structural compartmentation of mammalian cells and the differing functions of these compartments
Describe the structural compartmentation of mammalian cells and the differing functions of these compartments Introduction Cells with a membrane-bound nucleus are categorised in the eukaryote super kingdom [3]. Mammalian cells are one of four eukaryotic kingdoms, alongside Plantae, Fungi and Protista. Eukaryotes differ from prokaryotes in several ways, including their larger size, multicellular properties, the presence of a nucleus and membrane-bound organelles. Yet, it seems probable that eukaryotic cells evolved from prokaryotes, with the most likely explanation being the endosymbiotic theory. When looking under a powerful microscope at the ultrastructure of a mammalian cell we can see that it is compromised of several components. These subunits work together to form effective cell structures, which assemble into a tissue, which in turn construct an organism. Figure 1. The anatomy of an animal cell Source:http://molecular.magnet.fsu.edu/cells/animalcell.html Mammalian cells differ in structure depending on the ways in which they have specialised to carry out particular functions. The typical eukaryotic cell
Immunostaining and In Situ Hybridization Lab Report
[Type the company name] Immunostaining and In Situ Hybridization Lab Report Immunostaining and In Situ Hybridization Introduction and Theory The study of gene expression provides invaluable insight into an organism's structure and function; how it is that from a mere embryo genes can control which cells, tissues, organs and limbs will develop, providing the organism with the inherited traits that specifically adapt it to its forthcoming environment. Mutations of particular genes are sometimes associated with certain birth defects. Should an organism with a mutation in just one gene be born with a specific birth defect, it gives a clue as to the gene's function. The question of its intended function may be better understood by discovering whether it became inactive during development to cause the defect. Of the collective amount of genes inherited by an organism not all are actively expressed ("turned on" and functioning). If expressed, it will be transcribed into RNA, specifically mRNA, providing the coding blueprint for a particular protein. When inactive and not expressed, no RNA is transcribed and thus no protein produced, perhaps because the protein is no longer needed or not required in a particular area of the body. To prevent the unnecessary expenditure of energy a core feature of many organisms was similarly evolved to inactivate genes that serve no current
Discuss the role of CaMKII (calcium/calmodulin-dependent kinase II) autophosphorylation in learning and memory
Institute of Psychiatry MSc Neuroscience 2007 - 2008 FULL TIME STUDENT ESSAY Module 2: Essay Question No: 10 TITLE Discuss the role of CaMKII (calcium/calmodulin-dependent kinase II) autophosphorylation in learning and memory. WORD COUNT: 3043 MARKER'S COMMENTS: CANDIDATE NUMBER: K22563 PAGE NUMBER: 15 Discuss the role of CaMKII (calcium/calmodulin-dependent kinase II) autophosphorylation in learning and memory. In my essay, I will be discussing the mechanism of CaMKII autophosphorylation and how this process brings about LTP, which contributes to learning and memory. Furthermore I will talk about how the autophosphorylated kinase interacts with the postsynaptic receptors, which underlies the mechanisms of neuronal plasticity. Neural tissues contain many protein kinases and phosphatases and of these protein kinases, calcium-calmodulin dependent protein kinase II (CaMKII) plays an important role in learning and memory. CaMKII is a Ca2+-activated enzyme and makes up 1-2% of the total protein. The kinase is abundantly found in synapses and is one of the main proteins of the postsynaptic density in the vertebrate central nervous system. In mammals, there are more than 30 isoforms of CaMKII consisting of 4 genes, which are ?,?,? and ? and have molecular weights ranging from 52-83kDa. The main isoforms in the brain are ? and ?(Colbran et al, 2004). The ?-isoform is
How does Notch signalling mediate lateral inhibition? How is this mechanism thought to regulate timing in neurogenesis
Institute of Psychiatry MSc Neuroscience 2007 - 2008 FULL TIME STUDENT ESSAY Module 1: Essay Question No: 10 TITLE How does Notch signalling mediate lateral inhibition? How is this mechanism thought to regulate timing in neurogenesis? WORD COUNT: 2996 CANDIDATE NUMBER: K22563 PAGE NUMBER:15 How does Notch signalling mediate lateral inhibition? How is this mechanism thought to regulate timing in neurogenesis? In my essay I will be focusing on how Notch signals in the nervous system and how the ligand Delta mediates Notch signalling. In addition, I will also be explaining how various genes also play a role in lateral inhibition via Notch signalling. Furthermore I will explain how this mechanism regulates neurogenesis. Specification of cells at distinct times and places plays an important role for the production of cellular diversity in the vertebrate nervous system. Molecular signals that influence the generation of distinct cell types are spatially and temporally controlled. So therefore the neural pattern formation needs coordination of signals that provide temporal and spatial coordination. Lateral inhibition is one mechanism by which patterns of different cell types are produced and is a type of intercellular interaction by which a cell adopting the primary fate can inhibit its immediate neighbours from doing the same and therefore they adopt the secondary