Effect of Caffeine on the Heart Rate of Daphnia
Objective of Experiment: In 1819, caffeine (IUPAC nomenclature: 1,3,7-trimethyl- 1H-purine- 2,6(3H,7H)-dione) was discovered by a German chemist, Friedrich Ferdinand Runge. It is a bitter white crystalline xanthine that acts as a psychoactive stimulant drug and a mild diuretic in humans and other animals. Caffeine, an odourless and slightly bitter alkaloid, is found in coffee, tea ,kola nuts, ilex plants (the source of the Latin American drink maté ), and, in small amounts, in cocoa, where it acts as a natural pesticide that paralyzes and kills certain insects feeding on the plants. It is also known as guaranine when found in guarana, mateine when found in mate, and theine when found in tea; all of these names are synonyms for the same chemical compound. It is most commonly consumed by humans in infusions extracted from the cherries of the coffee plant and the leaves of the tea bush, as well as from various foods and drinks containing products derived from the kola nut. Other sources include yerba mate, guarana berries, and the Yaupon Holly. Caffeine is absorbed rapidly into the bloodstream from the gastro-intestinal tract in human whenever consumed. It reaches maximum concentration in circulatory system within about an hour. The blood distributes it throughout the body. It even manages to pass through the blood-brain barrier. Early experiments showed that low
Observing Mitosis. The purpose of this experiment is to prepare a slide of actively dividing plant tissue and to observe stages of the cell cycle in living tissue.
Observing Mitosis The purpose of this experiment is to prepare a slide of actively dividing plant tissue and to observe stages of the cell cycle in living tissue. We had to consider the duration of mitosis in relation to the whole cell cycle. First of all got some hydrochloric acid and put it into a water bath at 60°C. Then we cut off some root tips from garlic, we used the tips because it's where mitosis still takes place - the meristem. We put these roots into some acetic alcohol which is a fixative, so it stops and helps preserve the cells. Then we removed them and put them in ice cold water and then dried them on filter paper. After this we put the root tips in the pre-heated hydrochloric acid, this will dissolve the calcium pectate but leave the cell walls unharmed. So it breaks up tissue without damaging the cell. After cooling down again and drying, we put the root tips onto a clean microscope slide and cut off the tip of it. We had to make sure it was the meristem and not other differentiated root tissue. Then we macerated the root tip, this breaks up all the cells and makes them one layer. If not sufficiently macerated the layer may not be thin enough to observe cell nuclei. After this we added a small drop of acetic orcein stain so that we could see the cells under the microscope. We then added a cover slip over the cells, and blotted firmly to get rid of
To investigate the effect of Diastase on Starch
To investigate the effect of Diastase on Starch Aim The aim of this experiment was to investigate the breakdown of starch by diastase. There where a lot of different variables that could be changed. The possible variables that could be changed were: . Temperature The temperature of the water that the reaction was carried out in could be changed. 2. Concentration of Starch The concentration of the starch that will be used can be changed. 3. Concentration of Diastase The concentration of the diastase that will be used can be changed. 4. pH of Solutions The pH of both the solutions could be altered. 5. Volume of Starch The amount of starch that is used could be changed. 6. Volume of Diastase The amount of diastase that is used could be changed. 7. Amount of Iodine used The amount of iodine that is used could be changed. 8. Agitation The amount of agitation the test-tube is subjected to after the solutions are mixed. The variable that I am going to change is temperature. This is because it is one of the easiest to control and is almost guaranteed to get accurate results. Research in to Enzymes Enzymes are biological catalysts made up from protein that control vital biological processes. As we know catalysts are substances that speed up a rate of a reaction without itself being used up. An enzyme has an active site, which has a unique shape into which only
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
The Development of the Periodic Table of the Elements
The Development of the Periodic Table of the Elements The periodic table is defined as the most common arrangement of the periodic system. This is the classification of chemical elements into periods (corresponding to the filling of successive electron shells) and groups (corresponding to the number of valence electrons) and describes the modern version that is used today. However, this was not always how it was structured and described - like the atom, the Periodic Table has been developed over time due to the contributions of a number of scientists (and is still developing even today). Long before the development of the modern Periodic Table, ancient philosophers such as Aristotle believed the world to be made up of four distinct elements: earth, water, air and fire. Although this is not true, they were thinking along the right lines as these are examples of the states of matter solids, liquids, gases and plasma. The first significant contribution towards the modern Periodic Table was made by the French chemist Lavoisier in 1789, who with his wife compiled the first modern chemical textbook named Traite Elementaire de Chimie (Elementary Treatise of Chemistry), which included a list of the known elements at the time. An advantage of Lavoisier's work is that he distinguished between metals and non-metals but a disadvantage was that he included some compounds and mixtures
How can we prioritise species for conservation?
How can we prioritise species for conservation? Species becoming extinct: Species are facing various problems key to their survival such as destruction of animal habitats, damage to the natural environment of living things, for example trees are cut down to build homes, , Oil spills, acid rain and water pollution also add to the destruction of habitats. Moreover another cause for extinction is when animals are over-hunted for their meat, fur and other valuable parts.Another cause could be'when animals or plants arrive into a new habitat from a foreign place they sometimes introduce diseases that the native species can't fight. These "exotic" species can also prey on the native species'.[1] 'Ahmed Djoghlaf, head of the U.N. Convention on Biological Diversity stated that, "Extinction rates are rising by a factor of up to 1,000 above natural rates. Every hour, three species disappear. Every day, up to 150 species are lost. Every year, between 18,000 and 55,000 species become extinct. The cause: human activities." he said '.[2] Why conserve species: There are many advantages in conserving species not only the fact that we benefit from the diversity of animals and plants, as majority of our plants such as crops. Domestic animals are bred from wild relatives and can importantly benefit from the immense, scarcely tapped wild gene pools. Moreover Important requirements such as
Beetroot practical
Why does the colour leak out of cooked beetroot? The aim of this experiment is to investigate the effect of temperature on membrane structure. I predict that as the temperature of the water in which the beetroot is placed increases, the amount of pigment leaked will increase. My prediction is based on the concept that cell membrane will breakdown as the temperature rises. Apparatus * Corer * White tile * A Beetroot * Automatic Water Bath * Segregated knife * A thermometer * Stopwatch Method: * First I took the white tile and the corer. Then collected a cylinder of beetroot by pushing the corer into the beetroot and withdrawing it. The cylinder remains inside the corer. * I collected 2 cylinders, and cut them into 8 pieces of 1 cm with a segregated knife. Because the beetroot has been cut some of the cell membranes had been broken, which means some pigments leaked out. * I left the beetroot pieces in a beaker of distilled water for one night. * Next day I placed the beetroot pieces into tubes of 5 cm of distilled water and placed them into different baths with different temperatures between 0-70. * After 30 minutes I collected 2cm3 fluid from each water baht. * The fluid in each of the test tubes was analysed using a colorimeter The variables kept constant * ?The same diameter corer is used so to keep the surface area of each beetroot piece the same
Describe the molecular structure of starch (amylase), glycogen and cellulose, and relate these structures to their functions in living organisms.
Describe the molecular structure of starch (amylase), glycogen and cellulose, and relate these structures to their functions in living organisms. Carbohydrates are the main energy source for the human body. Chemically, carbohydrates are organic molecules in which carbon, hydrogen and oxygen bond together in the ratio: Cx(H2O)y where x and y are whole numbers that differ depending on the specific carbohydrate to which we are referring. Animals (including humans) break down carbohydrates during the process of metabolism to release energy. For example, the chemical metabolism of the sugar glucose is shown below: C6H12O6 + 6 O2 6 CO2 + 6 H2O + energy Animals obtain carbohydrates by eating foods that contain them, for example potatoes, rice, breads, etc. These carbohydrates are manufactured by plants during the process of photosynthesis. Plants harvest energy from sunlight to run the reaction described above in reverse: 6 CO2 + 6 H2O + energy (from sunlight) C6H12O6 + 6 O2 A potato, for example, is primarily a chemical storage system containing glucose molecules manufactured during photosynthesis. In a potato, however, those glucose molecules are bound together in a long chain. As it turns out, there are two types of carbohydrates, the simple sugars and those carbohydrates that are made of long chains of sugars - the complex carbohydrates. In this essay I am going to
The comparison of antibacterial properties of herbal products and standard antibiotics
The comparison of antibacterial properties of herbal products and standard antibiotics Introduction: This is As biology coursework, studying the area of microbiology the main investigation contains the comparison of antibacterial properties of herbal products and standard antibiotics. Aim: The aim is to investigate the effect of herbal products against standard antibiotics on bacteria growth. To examine the extent to which the herbal products (tea tree oil and peppermint oil) and the standard antibiotics (penicillin and streptomycin), reduce bacteria growth of E.coli and M.luteus. This will be discovered by measuring the growth of bacteria on the agar plates and comparing the results. Background information: The proposed aim surrounds the study of bacteria growth and various other products, which can have an affect on the growth rate; it is therefore necessary to look deeper into the topic criteria to get a wider understanding and to help design an appropriate hypothesis. From self-knowledge antibiotics are chemicals produced by microorganisms, which are designed to inhibit and destroy specific pathogens when used at low temperatures. Antibiotics release chemicals, which inhibit bacterial growth and work on a specific action site. The first founded antibiotic was penicillin discovered accidentally by Alexander Fleming in 1928 from a mold culture. It can be
Membrane permeability in beetroot cells.
Membrane Permeability in Beetroot cells Beet root cells contains a red pigment, which is found in the cell vacuole. The vacuole has a membrane in which its function is mainly to prevent the betacyanins from leaving the cell. Leakage of these betacyanins into the external solution can be used as an indication of membrance pereambility changes. As part of my experiment, my aim is to see if temperature affects the membrane by witnessing the amount of betacynanins that leaks from the beetroot cells. The cell membrane covers the outside of a cell and consists of a double layered sheet of lipid molecules interspered with proteins. It seperates the cell from the external environment, gives phyisical protection and allows the import and export of selected chemicals. Aim: I will commence the experiment by placing beetroots in a test tube of deionised water, I will use a range of temperatures in which I will place the beetroot cell to see the damage later on. After placing them in series of test tubes of deionised water for 30 minutes. I will pour out each solution into a cuvette and place it in a colorimeter, This will enable me to witness variations in my experiment. Prediction: My prediction to this investigation is that, as the tempertaure of the deionised water increases, so will the membrane permeability of the beetroot cell. In doing so, this will cause the beetroot
