Describe the Mechanism of Peptide Bond Hydrolysis by Serine Proteases and discuss the specificity of these enzymes
Describe the Mechanism of Peptide Bond Hydrolysis by Serine Proteases and discuss the specificity of these enzymes. Proteins are essential for all living systems and once used they need to be broken down into peptides and amino acids. These amino acids can then be recycled for the synthesis of more proteins. Berg et al (2002) stated that proteolytic reactions are also important in regulating the activity of certain enzymes. The hydrolysis of peptide bonds in the absence of a catalyst is extremely slow and a typical peptide bond in a neutral pH will have a hydrolysis half-life of between 10-1000 years (Berg, 2002). Berg (2002) explained that the resonance structure that accounts for the planarity of a peptide bond makes such bonds resistant to hydrolysis. This is because for every pair of amino acids linked by a peptide bond there are six atoms that lie in the same plane. Therefore it is essential to use a proteclytic enzyme or a protease to promote peptide bond cleavage. Serine proteases are used in the hydrolysis of peptide bonds and include chymotrypsin, elastase and trypsin. Proteases catalyse peptide bonds in polypeptides and proteins and according to Mathews et al (2000) serine proteases are distinct because they all have a serine residue that plays a critical role in the catalytic process. These serine proteases all have a similar three-dimensional
COMPLEMENT PRACTICAL The term "complement" was applied by Ehrlich to describe the activity in serum, which could "complement" the ability to specific antibody to cause lysis of bacteria (Immunology, Roitt et al, 4th ed). The complement system plays a crucial role in host defence against infectious agents and in the inflammatory process. It consists of twenty plasma proteins that function either as enzymes or as binding proteins that act as a cascade, where each enzyme acts as a catalyst for the next, with C3 being the most important component. The complement system also includes multiple distinct cell-surface receptors that exhibit specificity for the physiological fragments of complement proteins and that occur on inflammatory cells and cells of the immune system. The consequences of complement activation are: > Opsonisation > Activation of leucocytes > Inflammation > Lysis of target cells There are three different mechanisms that the complement system uses for recognising micro-organisms. The first pathway to be discovered was the classical pathway. It is activated by the binding of antibody molecules, specifically IgM and IgG1, 2 and 3 to a foreign particle i.e. antigens. Here, the complement proteins work together with antibodies to enhance the removal of antigen-antibody complexes from the body. Another common pathway is the alternative pathway. This
Describe the structure of keratin and collagen and show how their structures are suited to their biological functions. Discuss one disease/ metabolic disorder that can arise from a structural defect in either protein.
Describe the structure of keratin and collagen and show how their structures are suited to their biological functions. Discuss one disease/ metabolic disorder that can arise from a structural defect in either protein. Keratin and collagen are very vital within the body's structure; both are very similar in nature, being that they derive from amino acids, which make up their respective proteins. They both fall under a group of particular proteins known as scleroproteins or fibrous in nature. Majority of their structure consist of left-handed helix structures1. Scleroproteins make up one of the two major protein categories, the other being globular. Keratin and collagen each represent one of the three subclasses within scleroproteins. As scleroproteins their jobs are to provide support and protection for the body. They are adapt for this because of their complex structure of repeating polypeptide chains which strengthen as the bind together; this and their insolubility are vital in maintaining the anatomy of the body. Whilst being similar in some ways, collagen and keratin remain different in their specific functions and role. As mentioned above keratin is one of the three scleroproteins. It is an extremely strong, insoluble tertiary protein; it is the main constituent in the structures of various parts in the body. These include the skin, hair, nails, as well as horns and
Investigation into the integrity of cell membranes under different conditions Introduction Scientists have spent extensive time into researching the composition of the cell membrane. This flexible elastic material surrounding cell contents hold so much importance in the basis of cell functions. This practical in particular will make use of beet roots (plant cells), it is ideal because generally it is known that the cell membrane encases the cell's vital contents, and in beetroot is a red pigment that is enclosed in the cell membrane. By subjecting the beer root to different conditions, various knowledge regarding the composition and structure of the cell membrane can be obtained. Method The method has been slightly adapted for this practical due to limitations in the laboratory, thus the method is as follows: Effect of temperature on membrane permeability Prepare six test tubes by placing 15ml of distilled water in each one. Of the six, five will be labeled at different temperatures: 30?C, 40?C, 50?C, 60?C, and 70?C. The last test tube will be used as a control, so it will be at room temperature, which is about 26?C in the laboratory. These are all placed on a test tube rack and placed on the side somewhere. Next using boring tool 11 cylinders of beetroot should be cut from the beetroot. The cylinders should measure approximately two cm in length and 1 cm in diameter.
Not anything else but the experiment of cultivating seeds in different soils is the brightest memory of my primary school years. Ever since then, I really enjoyed studying natural sciences. Taking Biology Higher Level course has given me the deeper understanding of the processes of life around me. Nevertheless, lots of new areas of growth have opened to me, too; and I am determined to extent my knowledge further. Since the tenth grade, I have been attending two extramural scientists' schools, 'Pazinimas' and 'National Students Academy'. Education there is organized into sessions, composed of lectures, practice in the laboratory and exams; during which I have found myself the most involved in the molecular biology and genetics fields. Steve Jones 'The Language of Genes' is the book that gave me the insight of how significant and intriguing the processes in the cells' nuclei are. I started to read more about genetic modification, and its applications in medicine. It was very interesting to visit local Cardiology Institute where post doctorates are investigating how stem cells could be applied for patients with cardiopulmonary diseases. During the excursion, I learned how DNA is scanned for inconsistencies, and how TIRF microscope is used to observe the activity of sodium and calcium ions within the cells' membranes. Recently I have participated in one of the most successful
Sexual Dimorphism Displays in Genders of Uca longisignalis, Homo sapiens, and Poecilia latipinna Abstract The purpose of this experiment is to test whether sexual dimorphism exist in a range of species. In order to test our hypothesis which states that the mass, standard length and height in males did not differ from females in specie; we performed experiments on Uca longisignalis, Poecillia latipinna, and Homo sapiens. We found that the average for female crabs were 4.0 +/- 1.1 (S.D), the males were 2.3 +/- 0.6 (S.D), the human female average was 165.7+/- 3.4 (S.D.), the human male average was 182.1+/-8.1 (S.D.), the female fish average was 43.0+/- 4.3 (S.D), and the male fish average was 50.0 +/- 6.2 (S.D). In conclusion, we found that there is sexual dimorphism in all three species and that gender is a specie-specific factor that plays a role in sexual dimorphism. Introduction Throughout history, many intellectuals have tried to understand what makes males and females of the same species different. Until the modern era, the only known fact was that males and females differed greatly in physical appearances. However, with the advances in science, we know a great deal more about gender differences in numerous species. This is called sexual dimorphism. The purpose of the report is to discuss whether sexual dimorphism in size exists in a range of animals. In order to
All particles are in constant motion. In solid particles (ions, molecules, atoms etc) vibrate. In liquids they move more easily, while in gases they move randomly. Particles have a natural tendency to move from areas of their higher concentrations to areas of their lower concentrations. This is called 'DIFFUSION'; it is a passive process and does not need the use of energy. How quickly it happens depend on the difference between concentrations. OSMOSIS is a special case of diffusion where only water molecules are involved. It is the movement of water molecules from a region of higher water potential to a region of lower water potential across a PARTIALLY PERMEABLE MEMBRANE (1). Partially permeable membranes allow only small particles to flow through them. Living cells' membranes possess the same characteristics to control exchange of materials for their survival. The task is to find out the water potential of potato. This can be obtained by putting potato pieces in different water concentrations. The equipments that I will use are: * 50 cm3 beakers (5) * 2 potatoes * 25 cm3 measuring cylinder (2) * Cork borer (1) * A knife * Electric balance * 2 molar sucrose solution (1): CAMBRIDGE ADVANCED SCIENCES. BIOLOGY 1 PUBLISHED BY THE PRESS SYNDICATE OF THE UNIVERSITY OF CAMBRIDGE. Page 55-56. The following diagram shows the motion of water particles from
The Molecular Properties of Enzymes Sean Tavakoli March 8, 2010 Section: A020 Abstract: In this experiment, the effects of boiling and inhibitors on enzyme activity were studied. Methods used to carry out this study were the use of an indicator substance, methylene blue, and qualitative measurements of the changes in color that occur. Structurally similar substances were used as substrates and inhibitors in order to allow competitive inhibition to occur. A pH buffer was used in order to keep the pH constant for each sample observed. All of the test tubes were exposed to the same temperature so that all enzymes have the same rate of reaction, however for another set of experiments I changed the temperatures around to determine if heat had an effect on enzyme efficiency. The variables in this experiment were whether the enzyme was fresh or boiled and the presences of substrate and inhibitor. I hypothesized that the presence of an inhibitor hinders an enzymes ability to react with substrate. Also, that after boiling, an enzyme is unable to catalyze a reaction (Frankel 2009 et al pg 32 and 53) Introduction One of the most essential inferences to existence is credited to the rate and efficiency of chemical reactions that occur within an individual cell. In order for many of these reactions to be successful, they need a unique type of globular protein recognized as an enzyme.
Discuss the roles of the following in protein synthesis in mammalian cells:- the large and small subunits of the ribosome, mRNA, tRNA, release factors, SRP
Discuss the roles of the following in protein synthesis in mammalian cells:- the large and small subunits of the ribosome, mRNA, tRNA, release factors, SRP. Genes drive metabolism, growth and differentiation in living cells. They do this by promoting the synthesis of proteins which in turn catalyse many biological reactions. Therefore the synthesis of proteins is one of the most central and basic events in the life of every cell. The process of proteins synthesis is divided into two different parts; transcription and translation. Transcription is performed by RNA polymerase which uses one strand of the DNA helix as a template to synthesis messenger RNA (mRNA). This mRNA then migrates from the nucleus to the cytoplasm. Translation then occurs and according to Lodish et al (1995) this process is when the base sequence of the mRNA is used to order and to join the amino acids in the protein. To explain the roles of ribosomes, mRNA, transfer RNA (tRNA), release factors and signal recognition particles (SRP) the process of translation needs to be explained in more detail. The pathway of translation is divided into three main steps; initiation, elongation and termination. The mRNA has a protein coding region which is composed of a non-overlapping string of codons called an open reading frame. At the beginning of the open reading frame is a start codon and at the end there
Mabel Akinwumiju Molecular Cell Biology Lab Due: December 4, 2007 TA: Xiaoli Zhang Group #6 Polymerase Chain Reaction Materials and Methods: In order to perform polymerase chain reaction, the following cocktail was made: DNA template, deoxynucleotide triphosphates (dNTP), Taq polymerase, two primers, and a buffer solution. Before starting the PCR, first four samples were collected from the prime suspects and 19 uL "cocktail" was added. 1 uL of DNA from each suspect was placed into separate tubes, then 89 uL dH20, 6 uL dNTP, 3ul of forward primer, 3 uL of reverse primer, 1 uL Taq polymerase, and 12 uL 10X PCR buffer was added into each eppendorf tube. After thoroughly mixing, the samples were placed into the PCR tubes and then placed into the thermocyler. After the PCR cycle was preformed 2 uL of tracking dye was added to each sample and then they each were loaded into 7% acrylamide gel in 1X TBE solution for gel electrophoresis. The gel was run for approximately 1 1/2 hours at 240 volts, and then the gel was placed in an ethidium bromide solution for 10 minutes to help stain the DNA. Then the TA photographed it under a UV light. Results: After the gel electrophoresis procedure was complete, we were able to generate the PCR result The figure on the picture found in the appendix depicts the results that were obtained from the gel electrophoresis done for the