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
The effect of drugs on the nervous system
The effect of drugs on the nervous system A drug is defined as a substance that, when absorbed into the body, alters a normal bodily function. Some are able to do this, as they are capable of producing an array of different effects on the nervous system. The reason why affecting the nervous system of an organism is potentially so significant is due to the nature of it. The fact the nervous system directs the functions of all the tissues of the body demonstrates its considerable role within the body. It can therefore be assumed that taking substances which affect how it works may lead to a distortion in the way your body is run, producing unsafe side effects. The term nervous system is actually used to describe two divisions. The central nervous system (CNS) is the part which contains the brain and spinal cord. The peripheral nervous system (PNS) however, consists of all the sensory neurones used to detect stimuli. The PNS receives thousands of sensory inputs and transmits them to the brain via the spinal cord. The brain will then process this information, discarding around 99% of it as unimportant. After this sensory information has been processed, areas of the nervous system generate nerve impulses to organs or tissue and form a suitable response. As influences from chemicals are able to affect how the nervous system functions, it can be assumed that chemicals such as
Cellular Structure and Function
Cellular Structure and Function Introduction Cells are organised together into functioning groups called tissues. These groups of cells organise together to perform a specialised task. There are four basic types of tissues found in the human body; these are epithelial, connective, muscular, and nervous. The following text aims to explain the structure and function of these tissues as well as ovum and sperm cells. Epithelial Tissue Epithelial tissues, as with all different types of tissue, can be found all over the body, they generally line the inside or outside of a body cavity. The cells are anchored down by basement membranes and form in different shapes such a flat, cuboidal, and columnar. The below text details several different types of epithelium cells that can be located around the body. . Stratified Squamous Epithelium Stratified squamous epithelium cells are present in areas of the body that are very moist and subject to abrasion, such as the mouth, esophagus and vagina. The cells are packed densely together and are very flat and irregular in shape. The tissue functions to provide a barrier to entry to inside the body and protects underlying tissues from friction and drying. Figure A. above shows a drawing of the epithelia from an overhead point of view, in shape they are very similar to that of a fried egg. Figure B. shows the cells from a side-on point of
Investigating the effect of enzyme concentration on the activity of cellulase.
Individual Investigation Investigating the effect of enzyme concentration on the activity of cellulase Plan Hypothesis The concentration of cellulase will affect the rate of break down of cellulose to sugar. Prediction As the concentration of cellulase increases the rate of break down of cellulose to sugar will also increase. If the cellulase concentration doubles then the rate of break down of cellulose to sugar will also double. Biological Knowledge Cellulase is an enzyme that breaks down the cellulose in the plant cell wall into soluble glucose, cellobiase and higher glucose polymers. Cellulose (insoluble in water) Glucose (soluble in water) Together with the enzyme pectinase, cellulase is involved in the ripening of fruit. It causes the degradation of plant cell walls making the fruit soft. Enzymes have the following characteristic: * They are all proteins * They are catalysts found in living tissues * Each enzyme is able to promote only one type of chemical reaction * They accelerate chemical reactions but remain unchanged at the end of a reaction * They reduce the level of activation energy needed for a reaction * They work in an optimum temperature range and pH The lock and key mechanism is the theory behind enzyme action. The enzyme has a cavity with a precise shape called the active site. The substrate (the key), the compound that the enzyme
Measurement of protein solutions concentrations by biuret protein assay
Title: Measurement of protein solutions concentrations by biuret protein assay Objective: To study the principle a protein assay. To determine the absorbance rate of protein at different concentration by using spectrophotometer. To determine the concentration of unknown sample from the graph. Introduction: Protein quantitation is often necessary before processing protein samples for isolation, separation and analysis by chromatographic, electrophoresis and immunochemical techniques. Depending on the accuracy required and the amount and purity of the protein available, different methods are appropriate for determining protein concentration. Instead, several colorimetric, reagent-based protein assay techniques have been developed that are used by nearly every laboratory involved in protein research. Protein is added to the reagent, producing a colour change in proportion to the amount added. Proteins concentration is determined by reference to a standard curve consisting of known concentrations of a purified reference protein. Most pure protein solutions containing 1 mg/mL of protein have an absorbance of about 1.0 when the light path is 1 cm. This method is simple, rapid, and allows for full recovery of the protein. However, many other biochemicals absorb near this wavelength, making an accurate quantitation difficult. Furthermore, different
Analysing the vitamin C content in different fruit juices
Title : The Vitamin C Content in Fruit Juices Name : Yii Seng Ong Date : 28 August 2011 Class : 12M15 Student ID : 2011200378 Name of lecturer : Madam Ida Muryany binti Md. Yasin Objective . To determine and compare the concentration of vitamin C in different kind of fruit juices 2. To determine and compare the concentration of vitamin C in freshly prepared fruit juices and carton fruit juices Introduction . Vitamin C Vitamin C or also can be known as ascorbic acid is the elonic form of 3-oxo-L-gulofuranolactone. It can be synthesized from glucose or extracted from other plant sources such as blackcurrants, rose hips or citrus fruits. The empirical formula for vitamin C is C6H8O6. Other than that, the molecular weight for ascorbic acid is 176.1. Its melting point is about 190°C( with decomposition). The appearance is white to slightly yellowish crystalline powder. It is practically odourless, with a strong acidic property and a sour taste. Figure 1 : 2D structure of vitamin C Figure 2 : 3D structure of vitamin C Generally, vitamins are a group of complex organic compounds which play an essential role in animal metabolic process but which the animal cannot synthesis. Vitamins do not provide energy however, in their absence the animal develops certain deficiency diseases or other
Investigating respiration of maggots
Investigating respiration of maggots By Osman Khan Lee 13 Aim The aim of my investigation is to see how the rate of respiration of some maggots differs between room temperature and other temperatures, in terms of volume of oxygen produced. Simple Prediction I predict that as I raise the temperature of the maggots, the rate of respiration will increase. I think this because respiration is an enzyme-dependant process of reactions. Increasing the temperature will give the enzymes and substrates more kinetic energy and therefore will increase the rate of respiration. This is explained in further detail later on. Method . Using a syringe filled with manometer fluid, I will half fill a manometer. 2. I will then attach a 3-way tap to one of the delivery tubes on the bung and to this tap I will attach a syringe. 3. Next I will put 2g of soda lime in the bottom of each of the two boiling tubes, and will then place a gauze into each, which will rest slightly above the soda lime. 4. I shall then weigh some maggots using some measuring scales, and then put these into one of the boiling tubes, ensuring that none come into contact with the soda lime. After doing this I will place another gauze on top of the maggots to prevent them climbing up the tube. 5. I will then connect this boiling tube up with the manometer, as shown in the diagram. 6. I will then putt some glass beads
Find out if enzymes work faster or slower at different temperatures.
Nick Spong Biology 10/11/03 Introduction This is the plan and evaluation of an experiment to find out if enzymes work faster or slower at different temperatures. We will be timing how long it takes to see a cross through 20cm3 of Marvel milk solution at three different temperatures. We will be using the enzyme neutrase to break down Marvel milk. Hypothesis My hypothesis (theory) is that at temperatures over 40°c the neutrase will be increasingly denatured and the milk will not clarify. Under 40°c the neutrase will be slowed down. However I predict that at 40°c the neutrase will be working well as this temperature is near its optimum temperature and so the milk will decolorize the fastest. I have made my prediction based on the following evidence: The reason that the milk will decolorize or do anything at all is because neutrase is an enzyme. Enzymes are biological catalysts. This means that they are a biological life form that catalyses (speeds up) a process. They have an optimum temperature and pH. Both of these have to be almost exactly right, otherwise their performance deteriorates rapidly. In high temperatures the enzyme will be denatured and will not work even if you bring the temperature back down. However, at low temperatures, and low and high pH's, all you have to do is bring the environment close to the enzyme's optimum environment and the enzyme
The Effect Of Temperature on the Respiration Of Yeast.
The Effect Of Temperature on the Respiration Of Yeast Introduction: - I am going to find out how temperature effects the respitory action of yeast. I am going to do this by using six different temperatures, 25oC, 30oC, 35oC, 40oC, 45oC and 50oC and a solution called TTC which is absorbed by the yeast cells turning them pink when hydrogen is removed from the metabolic pathway by the dehydrogenase enzyme. Background Information: - Yeast: - Yeast is unicellular fungus that buds profusely under favourable conditions. They are classified as sac-fungi (Ascomyctes) even though they are unicellular. Yeast is common in areas where there is sugar because of this they are given the name saccharomyces (Sugar fungi). They grow on the surface of fruits, in the nectar of flowers, in sap excluded from trees, in the soil and in fresh water. Yeasts are used in all sorts of arrears such as alcoholic fermentation (fermentation is the name given only to the anaerobic respiration of yeast) to baking bread. Yeasts are of a great economic importance and are yeast for biochemical research for example in respiration and enzymes. Yeast exists as Diploid or Haploid cells and divides by mitosis and meiosis. Yeasts are not plant or animal because they do not photosynthesise and they do not have any chloroplast. Yeast is a saprophyte. This is an organism, which obtains its nutrients from dead or
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
