Investigating the breakdown of hydrogen peroxide using celery tissue to supply the enzyme catalyst
Investigating the breakdown of hydrogen peroxide using celery tissue to supply the enzyme catalyst Variables * Amount of celery * Concentration of celery, more or less watered down. * Concentration of Hydrogen Peroxide (H202) * The amount of H202 * The temperature of H202 I am going to vary the concentration of the hydrogen peroxide. I think that varying the concentration of the liquid will be the best experiment to do and will hopefully give a strong set of results, which will enable me to obtain clear conclusions. Prediction The rate of an enzyme- controlled reaction depends on the temperature, pH, and concentrations of the enzyme and its substrate. The more enzyme molecules produced by a cell, the faster the reaction will proceed. Similarly, an increase in the substrate concentration will speed up the reaction if there are enough enzymes molecules to cope with the additional substrate. Therefore by diluting the hydrogen peroxide with water, this will decrease the rate of decomposition of the H202, and the less gas will be given off. The enzyme in the experiment is catalase. Hydrogen peroxide is poisonous and the catalase works to render the hydrogen peroxide harmless by breaking it down to water and oxygen. If the concentration of H202 is less, then there is more water present, and there are less hydrogen peroxide molecules, so there is less for the catalase to
Investigate the effect of pH on Trypsin
Biology Coursework Plan Aim Investigate the effect of pH on Trypsin Prediction / hypothesis * pH will affect trypsin action * as pH increases, tryrpsin will show increasing activity up to an optimum pH * the action of the enzyme trypsin on the substrate egg albumen will be at a maximum at an optimum pH of around 7 (neutral) to 8 (slightly alkaline) see later about pH of duodenum * as pH continues above this, trypsin activity will decrease Background / Introduction Proteins are complex organic compounds consisting of amino acids joined by peptide bonds which form highly folded three dimensional or tertiary structures. The bonds that maintain the tertiary structure of the protein are a result of interactions between the R groups of the amino acids: disulphide bridges (strong covalent), hydrogen (weak) bonds, ionic or electrovalent bonds, hydrophobic interactions. Enzymes, such as trypsin, are globular proteins with a specific shaped active site into which the correct substrate can fit. trypsin protein / polypeptide peptides Trypsin is a protease enzyme: a hydrolytic or digestive protein that cleaves peptide bonds. It is produced in the pancreas in the form of trypsinogen, and is then transported to the duodenum of the small intestine, where the digestion of proteins to polypeptides and amino acids begins. The pH
Cellular Respiration and the Role of Mitochondria
Cellular Respiration and the Role of Mitochondria Cellular respiration is the process of oxidising food molecules, such as glucose, to carbon dioxide and water and releasing the covalent bond energy in the form of ATP for use by all the energy-consuming activities of the cell. Mitochondria are membrane-enclosed organelles distributed through the cytosol of most eukaryotic cells. They are where cellular aerobic respiration occurs; indeed cells without mitochondria cannot respire aerobically. Cellular respiration consists of two broad phases, initially, glycolysis (the breakdown of glucose to pyruvic acid) Occurs, this is followed by the oxidation of pyruvic acid to carbon dioxide and water. In eukaryotes, glycolysis occurs in the cytosol (The fluid in which cell organelles are suspended). The remaining processes take place in the mitochondria. The first stage, glycolysis is the anaerobic catabolism of glucose, it occurs in almost all cells. The process uses glucose and co-enzyme NAD (Nicotinamide Adenine Dinucleotide), and yields 2 molecules of Pyruvic acid, as below C6H12O6 + 2NAD+ -> 2C3H4O3 + 2NADH + 2H+ The free energy stored in 2 molecules of pyruvic acid is somewhat less than that in the original glucose molecule. Some of this difference is captured in 2 molecules of ATP. The Krebs Cycle then decarboxylates the pyruvic acid resulting in a 2-carbon fragment of
The structure and function of the ileum in relation to absorption and digestion.
SUMUDU LANKATILAKE 7-FEB-03 THE STRUCTURE AND FUNCTION OF THE ILEUM IN RELATION TO ABSORPTION AND DIGESTION The ileum is the second part of the small intestine located after the duodenum. It has a vital function in digestion and has a suitable structure to accommodate for its functions. The ileum is 6 meters long and the main site foe the absorption of the soluble products of digestion. The ileum is efficient at this for the following reasons: * It is fairly long and presents a large absorbing suface to the digested food. * Its internal surface is greatly increased by circular folds bearing thousands of projections called villi. These villi are about 0.56mm long and may be finger like or flattened in shape. * The lining epithelium is very thin and the fluids can pass rapidly through it. The outer membrane of each epithelial cell has microvilli which increase the exposed surface of the cell by 20 times. * There is a dense network of blood capillaries in each villus for quick absorption and maintainance of the concentration of the concentration gradient. * The villi possess smooth muscle fibres that contract and relax and mix the food up and bring it into contact with the epithelial cells of the absorptive surface. * Each villus has a lacteal for the absorption of fatty acids and glycerol, most of which combine to form fats. The ileum is made up of 4 layers:
Relating the structure and function of cell organelles
Relate the structure and function of cell organelles Cells are like cities with intricate organelles 'living and working' in it. There are basically two kinds of cells, namely Prokaryotic and Eukaryotic. Both plant cells and animal cells are eukaryotic while prokaryotic cells are simplier organisms that possess non-membrane bounded organelles. In most cells they contains the following organelles which carry out unique functions and allow cells to work properly. To start off with, nucleus is a large roundish organelle enclosed by a double membrane with numerous openings, namely nuclear pores, for nuclear traffic. It contains chromosomes and one or more nucleoli. Nucleolus is a spherical site where ribosomes are formed. Chromosomes contain DNA which tends to be packed in form of chromatin. Only during interphrase (a stage before a cell divides in a cell division process), chromosomes will be unravelled for easier replication. Tiny, hollow cylinders of protein called centrioles form a network of spindle fibres in the nucleus during nuclear division to pull chromosomes apart. The inner membrane of nucleus will break down and allow chromosomes lying freely in cytoplasm. DNA contains the genetic information and control the synthesis of protein. Each cell contains millions of ribosomes. They are very tiny, non-membrane bounded organelles made of protein and RNA which consist of
structural differences between fibrous and globular proteins.
Question: Explain with examples, the structural differences between fibrous and globular proteins. A globular protein has a fixed specific sequence of amino acids that are non-repetitive while a fibrous protein has a repetitive regular sequence of amino acid. For example, haemoglobin, a globular protein is made up of 4 polypeptide chains to form a tetramer (?2?2), composed of two identical alpha-beta (??) dimers. Collagen, a fibrous protein, has a primary structure characterized by a repeating tripeptide sequence of Glycine - X - Y. (X is proline, Y is either hydroxyproline or hydroxylysine) A globular protein has a more compact structure owing to highly contorted pattern of folding, bending and twisting along polypeptide chain to give the protein a spherical 3D shape while a fibrous protein is usually formed with elongated polypeptide chains wrapped around to form multi-molecular paralleled filaments to strands. For example, haemoglobin is a tetramer made up of 4 polypeptide chains of 2? chains and 2? chains. These four subunits are packed to form an overall spherically shaped molecule. However, collagen, a fibrous protein, is formed with three polypeptide chains lie parallel and wind round one another, forming a tropocollagen. The tropocollagen molecules lie side by side and are linked to each other giving a collagen fibril. A globular protein has its length of
The Function and Structure of Lipids in Living Organisms
The Function and Structure of Lipids in Living Organisms Lipids are a group of organic compounds that are fatty acids and include Oils, Fats, Waxes and Steroids. They are also all insoluble in water because they are non-polar but are soluble in solvents, which is why solvents are often used in home cleaning products like oven cleaners and drain cleaners to remove build-up's of fats and oils. Also lipids like wax can be very useful and vital for many creatures such as bird and semi-aquatic mammals which use them to make their feathers fur waterproof. Similarly humans use keratin in the epidermis and oil produced by the sebaceous glands help to make their skin waterproof(1). The structure of lipids Lipids similar to carbohydrates contain carbon, oxygen and hydrogen, but in lipids the proportion of oxygen is a lot lower than carbohydrates. Also lipids are insoluble in water because they are non-polar which means that the positive and negative charges cancel out each other so it doesn't have a positive or negative charge but they are soluble in organic solvents such as ethane and methane because they are also non-polar. Fatty acids can be saturated or unsaturated depending on their carbon bonding and can be told apart easily because of their state at room temperature, ether solid or liquid. Saturated fatty acids are made up of hydrogen, oxygen and carbon, the carbon in the
Factors effecting enzyme activity
Biology Coursework Factors effecting enzyme activity Aim: To investigate the effect of temperature on the rate of catalase activity. Enzymes are proteins that act as catalysts, which are made in the cells. A catalyst is a chemical substance that speeds up a reaction but does not get used up in the process. Enzymes can be used over and over. There are two types of enzyme reactivity, these are called anabolic and catabolic reactions. An anabolic reaction is where large molecules are built up from smaller molecule. A catabolic reaction is where reactions split large molecules into smaller ones. Enzymes work by a method called the lock and key method: Basically it works by the enzyme meeting the substrate and they both fit together well to make an enzyme-substrate complex. This works well because enzymes have a definite three dimensional shapes which is complementary to the shape of the substrate. In the enzyme-substrate complex, the substrate attaches to an area on the enzymes known as the active site. The enzyme is then free to react again with any available substrate. Catalase can be found, not just in humans but in potatoes, apples and the liver. During my preliminary work, I will be investigating which of these gives off the most oxygen. The one which gives off the most oxygen will be the catalase that I use during my experiments. This way it will give me the best
Features of Lungs & Tissues
I am going to compare different tissues with similarities, including what cells are in the tissues and where they are located and what organelles are within the cells, also to state their functions including explaining how each tissue is able to carry out their role. Firstly I will compare (Alveolus of lung/Bronchus of lung), secondly (Stomach/Urinary bladder). Alveolus of lung Bronchus of lung What cells are in the tissues? There are three types of cells within the tissue (Type I, Type II and Macrophages). * Type I (Squamous Alveolar) cells that form the structure of an alveolar wall * Type II (Great Alveolar) cells that secrete pulmonary surfactant to lower the surface tension of water and allow the membrane to separate, thereby increasing the capability to exchange gases. Surfactant is continuously released by exocytosis. It forms an underlying aqueous protein-containing hypophase and an overlying phospholipid film composed primarily of dipalmitoyl phosphatidylcholine. * Macrophages that destroy foreign material, such as bacteria. Where they are located? Type II cell is located in the alveolar epithelium. Macrophage cell is found in the pulmonary alveolus, near the pneumocytes, but separated from the wall and type I cell is located beneath the plasmalemma . Main organelles within the cell? Organelles found within the cells are as follows: Nucleus,
Determination of Vitamin C in food
.2 Determination of Vitamin C in food Vitamin C, L-ascorbic acid or L-ascorbate is an essential nutrient in humans. This is because we cannot synthesis the vitamin from glucose in the liver. It is thought that the absence of an enzyme l-gulonolactone oxidase from liver cells1 prevents humans from converting glucose into ascorbic acid. Ascorbic acid functions as an anti-oxidant in living organisms protecting the body against the effect of oxidative stress. Ascorbic acid is also important biologically as it is used as a cofactor in enzymatic reactions (no less than 8 reactions have been identified). These include the synthesis of collagen, a deficiency of which leads to the most notable disease of vitamin c loss, scurvy. Ascorbic acid forms the part of many important physiological functions. These include the syntheses of collagen, neurotransmitters, tyrosine carnitine and metabolism of microsome2. But most importantly it is known for its antioxidant activity. When free radicals are present in cells as high levels they are thought to have an effect on cardiovascular disease, high blood pressure and chronic inflammatory diseases3. It is thought that ascorbic acid reacts with these free radicals preventing them from causing damage to cells. How to measure the amount of Vitamin C in food One way to measure the amount of vitamin C in our food is to use what is called a redox
