The biochemical nature oflight detection and emission
The biochemical nature of light detection and emission In this essay I aim to describe the range of biochemical pathways and mechanisms used by living organisms both to detect and to emit light. I will discuss general principles employed, and illustrate the range of different biochemistry involved by the use of many specific examples. Light Detection I will discuss the mechanism and function of light detection by five groups of light detecting molecule. The biggest of these is the rhodopsin group of proteins, I will also look at the role of phytochromes, cryptochromes, flavoproteins and porphirins in light detection. Rhodopsins are found in a diverse array of organisms, all featuring a retinoid prosthetic group linked to a an apo-protein, opsin via a protonated schiff base linkage. Electrons from the schiff base lone pair occupy an extra orbital (the 'n orbital'), therefore electrons can undergo a n-p* transition as well as a p-p* transition. Retinal proteins were first discovered in 1876 by Bell, who observed a reddish pigment that bleaches on exposure to light, which he called visual purple. Most rhodopsins contain retinal as the prosthetic group, but some have one of the other chromophores as shown below. For example freshwater fish have a rhodopsin containing 3,4-didehydroretinal, which has a red shifted UV absorption band. The opsins found in all organisms
Investigation Of The Respiratory Chain In Mitochndria. The experiments were carried out to investigate electron transport of the respiratory chain of yeast mitochondria and to examine the effects of different compounds on the chain. This was done using s
Introduction The experiments were carried out to investigate electron transport of the respiratory chain of yeast mitochondria and to examine the effects of different compounds on the chain. This was done using spectrometry and the absorbance spectral properties of a redox dye (DCPIP), which acts as an artificial electron donor/acceptor. Method For safety guidelines, the apparatus and the techniques employed when carrying out the experiment, see the attached, workshop handout. Results Results Table Experiment A Minutes Experiment 1 (Part 2) Absorbance Experiment 1 (Part 3) Absorbance Experiment 1 (Part 4) Absorbance Experiment 1(Part 5) Absorbance 0 0.96 0.95 0.91 0.54 0.5 0.96 0.95 0.895 0.54 0.96 0.95 0.87 0.54 .5 0.96 0.94 0.85 0.54 2 0.96 0.94 0.83 0.54 2.5 0.96 0.94 0.81 0.54 3 0.96 0.94 0.79 0.545 3.5 0.96 0.94 0.77 0.545 4 0.96 0.935 0.76 0.545 4.5 0.96 0.935 0.735 0.545 5 0.96 0.935 0.72 0.55 5.5 0.705 6 0.69 6.5 0.655 7 0.65 7.5 0.64 8 0.625 8.5 0.61 9 0.6 9.5 0.585 0 0.57 0.5 0.56 1 0.55 1.5 0.54 2 0.53 2.5 0.515 3 0.51 3.5 0.49 4 0.48 4.5 0.475 5 0.46 Results Table Experiment B Minutes Experiment B (Part 1) Experiment B (Part 2) Experiment B (Part 3) 0 0.91 0.84 0.75 0.86 0.84 0.61 2 0.81 0.83 0.54 3 0.77 0.825 0.52 4 0.73 0.825 0.515
Nucleotide Excision Repair
The Importance of DNA Repair Systems and Process of Nucleotide Excision Repair Name: Thien Nguyen ID: 20299974 TA: Kristyna Wilson Bio 130 Tutorial Tuesday, November 10th 2009 As we go about our daily lives, our cells are hard at work to maintain our well-being. Whether it is providing the energy required doing everyday tasks or just repairing what has been damaged from the constant bombardment of harmful forces, the cell is a formidable force on its own. And it should, because within every cell, DNA enclosed, which is the genetic information that houses the instructions for an organism to function and also a very vulnerable part of the cell to harmful alterations. With radiation, the backbone of a DNA is broken, when exposed to reactive chemicals or UV light; the DNA's bases can be altered structurally (Karp, 2008). While there are many mechanisms for repair for DNA, the nucleotide excision repair (NER) is one of the most effective and versatile repair systems within the cell that acts on the DNA. The reasons for this is because of its ability to recognize, remove a wide variety of alterations in the DNA called lesions, and replacing the damaged part of the DNA (Leibeling et al, 2006). Before this system can do any work on the damaged part of the DNA, it must recognize the lesion first. There are two ways pathways in which the nucleotide excision repair can
Discuss the stereochemistry of monosaccharides, nucleotides and amino acids
Discuss the stereochemistry of monosaccharides, nucleotides and amino acids. How does the stereochemistry of these building blocks affect the structures of the polymers that they form? Stereoisomers[a] have the same displayed formula but a different arrangement of atoms in space. Enantiomers rotate plane polarised light in opposite ways – each is known as either the D or L form (although this naming originally indicated which way the light was rotated, the fact that this cannot be predicted from atomic structure means that we instead compare the molecule to a similar known one – for example all monosaccharides and amino acids are named based on the structure of glyceraldehyde). The two enantiomers are non-superimposable mirror images of each other - they have a chiral centre (often a carbon atom with four different groups of atoms covalently bonded to it[b]). Monosaccharides[c] Monosaccharides (sugars) are the monomers of polysaccharides (carbohydrates), linked by O-glycosidic bonds which are formed from condensation reactions between the monosaccharides. Monosaccharides have a chiral centre [d]– the carbon one from the end of the chain furthest from the carbonyl group[e]. By convention, the arrangement of atoms in space around this carbon is used to dictate whether the monosaccharide is in its D or L form – although many of the other carbons in the chain are also
Translocation of soluble products of photosynthesis occurs in the part of the vascular tissue known as the phloem.
Transport system in a plant is concerned with the movement of materials from source to sinks. According to Lacher .W 1985, a source is a region of a plant, which is manufactures sugars during photosynthesis and supplies materials of any kind to the transport system (e.g leaves) and a sink as a region where the sugars and minerals are being removed or lost from the system to be used up or stored (for example the root and production of fruit). Transport of soluble products of photosynthesis is called translocation. Translocation of soluble products of photosynthesis occurs in the part of the vascular tissue known as the phloem. The phloem is the principle food conducting tissue associated with xylem in the vascular system. The basic components of phloem are sieve elements, companion cells and phloem parenchyma and phloem fibres. It is placed outside the cambium of the vascular bundle (www./http://infotrac.thomsonlearning.com). It is well known that soluble products of photosynthesis formed in the photosynthetic tissue, enter the sieve tubes by active transport. The movement of materials once they are in the sieve tubes is still under debate as to which and what is the driving force. Although sugars and amino acids tend to move along concentration gradients the speed at which they travel is too fast to be explained simply by diffusion. There presently four proposals of
Mammalian cell structure
DESCRIBE THE STRUCTURAL COMPARTMENTATION OF MAMMALIAN CELLS AND THE DIFFERING FUNCTIONS OF THESE COMPARTMENTS In this essay I would like to talk about the compartmentalisation of the cell and some important processes happen within the cell that requires the corporation of different organelles. Eukaryotic cells (from the Greek meaning truly nuclear) can be easily distinguished through a membrane-bound nucleus. Mammalian cells are one of the two types of eukaryotic cells, in which contains many internal membrane bounded structures called organelles, they are separated into different groups in order to increase their efficiency at bringing out particular function, and this is called compartmentalization, however there is processes that requires different organelles working together in order to take place, such as respiration (involves the cytoplasm and mitochondria) and Protein Synthesis (Nucleus, Ribosomes). Mammalian cells are different to Plant cells (which are also eukaryotic), they do not have a cellulose cell wall, and they are bounded by only plasma membrane, so they are sensitive to Osmotic lysis (the bursting or rupturing of the plasma membrane due to osmotic movement of water into the cell when the cell is in a hypotonic environment. The command centre of the cell, usually the largest is the nucleus; it contains the DNA information (chromosomes) of the cell and
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
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
HIV and AIDS
Will HIV and AIDS be seen as the black death of the 21st century? Human Immunodeficiency Virus (HIV) is seen by many as the "Black Death" of the 21st century, however, it is unlikly that it will have the detrimental effects that the Bubonic Plague had on society. I will state the many reasons why this should not be seen as such a drastic effect by exploring, the prevention, media,reconition, treatment and the primary cause's of these diseases. I will also explore the stigma behind H.I.V and AIDs which causes them to be seen as the Black Plague of the 21st century ie, death toll,drug resistance,denial,silent symptoms and the ongoing problems with treatment. AIDS is caused by the HIV virus it enters the body in numerous ways. The HIV virus is deadly because it seeks out and attacks white blood cells called T4 lymphocytes these are used to coordinate the body's immune defence system. Hubley, J. (1990). The Aids Handbook. pp 9-11. MACMILLAN PRESS LTD The HIV virus takes over these cells and uses DNA to replicate. The T4 cells then produce lots of HIV virus particles which break out instantly killing the T-lymphocyte cell. These copies of the virus then attach to any new T-lymphocyte cells that are created. For a while the body is able to keep the immune system working properly however there comes a point when the body is no longer able to keep up with virus and your
DETERMINATION OF THE VALENCY OF THE MAGNESIUM
NAME: THAMARAI A/P RAJENDRAN ID NUMBER: 09ALB07214 LABORATORY 1A: ATOMIC STRUCTURE, BONDING AND PERIODICITY COURSE: BIOTECHNOLOGY (YEAR 1 SEM 1) EXPERIMENT 6: DETERMINATION OF THE VALENCY OF MAGNESIUM TITLE: Determination of the Valency of Magnesium OBJECTIVES OF EXPERIMENT: This experiment is to study the quantitative relations between amounts of reactants and products of a reaction. A known starting mass of magnesium and the measured collection of hydrogen gas will be used to determine the reaction stoichiometry. THEORY AND BACKGROUND: Stoichiometry is the study of the quantitative relations between amounts of reactants and products of a reaction (that is how many moles of a reactant A react with a given number of moles of B). in this section, a known starting mass of magnesium and the measured collection of hydrogen gas will be used to determine the reaction stoichiometry. The term stoichiometry is also often used for the molar proportions of elements in stoichiometric compounds. For example, the stoichiometry of hydrogen and oxygen in H2O is 2:1. In stoichiometric compounds, the molar proportions are whole numbers (that is what the law of definite proportions is about). Stoichiometry is not only used to balance chemical equations but also used in conversions, i.e., converting from grams to moles, or from grams to milliliters. Reaction stoichiometry allows