Explain the link between cancer and mitosis. Describe how the chances of cancer developing in the human body may be increased.
Explain the link between cancer and mitosis. Describe how the chances of cancer developing in the human body may be increased. Cancer is one of the most common diseases in the developed countries, accounting for around one in four deaths. In Britain it caused about 25% of the deaths h in 1991 and is the most common cause of death following cardiovascular disease. There are, in fact, over 200 different forms of cancer, which is why it is not necessarily thought of as a single disease. For example, breast cancer is the most common form in women and lung cancer in men. Cancers are a result of uncontrolled mitotic cell division, which is the division of one cell to produce two genetically identical daughter cells. The problem is cased by mutations or abnormal activation of the genes which control cell division. We can say that a gene has been mutated if there is a change in one of the bases; for example, one base turns (e.g. adenine) into another base (e.g. thymine). This can lead to uncontrolled cell division. When genes are abnormal (or have been mutated) they are called oncogenes (onkos means tumour), about a hundred of which have been discovered. Cancerous cells will divide uncontrollably and repeatedly forming clones of genetically identical cells. Therefore, thought the mutation may start off in only one cell, it can be passed on to the cells decedents, so the daughter
Global Warming
> Global Warming can be defined as the term used to refer to the fact that the average temperature around the earth is increasing. > Global Warming is caused by many different factors which are mostly as a result of human activities such as the burning of fossil fuels like coal, oil and wood which produce carbon dioxide > The excess Carbon Dioxide that is released in the atmosphere is also contributed by the emission of fumes by factories and motor vehicles. The extra carbon dioxide therefore creates a 'blanket' around the earth resulting in the rapid increase of temperature > Over the past century there has been a marked increase in the concentration of he Greenhouse gases. Greenhouse Gases include carbon dioxide, water vapour, methane, nitrous oxide and ozone. > The Green house gases are also play a huge role in global warming as these gases trap the heat that would otherwise escape to into space. This is called the greenhouse effect > Deforestation is also another cause of global warming because when the excess amount of trees are cut down and not replanted, there becomes an increase in Carbon Dioxide concentration in the atmosphere as there are no trees to use it for respiration. This Carbon dioxide therefore plays a role in global warming as it begins to trap heat on the earth's surface. Consequences of Global Warming > Global warming results in many changes in
How caffeine affects Daphnia heartbeat?
An experiment to determine how caffeine affects the heart rate of Daphnia (water fleas)? Introduction The purpose of this experiment is to determine whether or not caffeine has an affect on the heart rate of Daphnia Hypothesis The Daphnia heart rate will increase with the concentration of caffeine. I based my hypothesis on the fact that humans heart rates increase with caffeine as it acts as a stimulant drug. In the experiment there will be several variables that I need to try and control, the temperature of the water is one of these because if the temperature is higher or lower on the day the results may end up being higher or lower, this would make my results inaccurate. I need to try and limit the human error in the experiment as the daphnia heartbeat is very quick so it will be hard to be completely accurate so we are using the "blind method". We need to use the same microscope throughout testing as others may have different strength lenses. I am also going to keep the species of daphnia the same, as different species may react differently to the caffeine. I will use the same type of caffeine and record the amount of time the daphnia spend in the caffeine before the counting begins, and try to keep this to a similar range. The independent variable I will change is the concentration of caffeine in the water. I am going to be testing 0.1%, and 0.5% caffeine and also
Coronary Heart Disease
Coronary Heart Disease: The risks and factors The heart is a crucial muscle in the body, it pumps on average five litres of blood a minute around the body. The heart itself has its own blood supply from a network of blood vessels on the surface of the heart known as the coronary arteries. Coronary Heart Disease (CHD) is formed when the supply of blood to the heart is blocked off due to the build up of fatty substances in these coronary arteries. CHD has numerous causes and thus it is the UK's biggest killer with approximately 300,000 people having a heart attack each year. Cholesterol is one of the four main causes of CHD, it is made in the liver from saturated fats and is carried through the blood stream by lipoproteins. There are also many different types of lipoproteins, but the main two are low density lipoproteins (LDL) and high density lipoproteins (HDL). LDL cholesterol builds up in the coronary arteries, which can then cause CHD as mentioned previously. Whereas HDL cholesterol does the opposite and takes the cholesterol away from the cells and back to the liver, thus this is often referred as the good cholesterol. A good total blood cholesterol level is 5 or lower, as if you allow your LDL level to get too high the HDL will not be to remove the cholesterol sufficiently. CHD can even happen to the fittest of people, for example a footballer in Spain last year
A Colorimetric Method for the Estimation of Glucose in Solution.
A Colorimetric Method for the Estimation of Glucose in Solution Method A clean pipette was used to transfer 10cm of 10% glucose into a boiling tube. The pipette was then used to transfer 9cm of 10% glucose into a different boiling tube. 1 cm of distilled water was added to give 10cm of 9% glucose. This was repeated to make 10cm of 8%, 7%, 6%, 5%, 4%, 3%, 2%, and 1% glucose solutions (use the table below to help): Concentration of glucose (%) Volume of 10% glucose to transfer (cm ) Volume of distilled water to transfer (cm ) Total volume of solution (cm ) 0 0 0 0 9 9 0 8 8 2 0 7 7 3 0 6 6 4 0 5 5 5 0 4 4 6 0 3 3 7 0 2 2 8 0 9 0 A clean pipette was used to transfer 5 cm of 1M sulphuric acid into each solution. A clean pipette and pipette filler was used to transfer 2cm of potassium permanganate solution into each boiling tube. A stopwatch was started the exact moment the potassium permanganate was added to the acidified glucose solutions. A time was recorded, in seconds for the complete decolourisation of the potassium permanganate solutions. Results Concentration of glucose (%) Start time (seconds) Finish time (seconds) Elapsed time (seconds) 0 90 562 472 9 80 578 498 8 70 590 520 7 60 605 545 6 50 614 564 5 40 629 589 4 30 635 605 3 20 963 943 2 0 787 777 0 2486 2486 Results of
"An investigation to find out the optimum temperature for the activity of Lipase".
"AN INVESTIGATION TO FIND OUT THE OPTIMUM TEMPERATURE FOR THE ACTIVITY OF LIPASE" * AIM To investigate the effect of temperature has on enzyme activity and to investigate the hypothesis that there is an optimum temperature for the activity of the enzyme lipase. * INTRODUCTION Enzymes are biological catalysts made up of protein molecules, usually with a globular structure. They accelerate chemical reactions in organisms that would otherwise occur to slow. (Green, Stout, Taylor, 1991) An enzyme that breaks down larger molecules into smaller ones is known as a breaker enzyme and involves a catabolic reaction. Where as builder enzymes build large molecules from smaller ones, and involve an anabolic reaction Lipase involves a catabolic reaction and is a digestive pancreatic enzyme which works to hydrolyses fats into glycerol and fatty acids. (Simpkins, Williams, 1987) These products will react with the Sodium Carbonate (put into the mixture to raise the pH) and in effect lower the pH level towards a more acidic content. This pH change can be observed by using the indicator Phenolphthalein, which changes from a pink colour to colourless at a pH below 8.3. * HYPOTHESIS Lipase is an enzyme found in the human body and from knowledge of human enzymes I expect the optimum temperature to be around 40°C. I expect as the temperature is lowered the rate of reaction will be slower
How Does Temperature Affect the Action of Amylase on Starch?
How Does Temperature Affect the Action of Amylase on Starch? Hypothesis: When the temperature is raised, the will amylase will break down the starch quicker according to the temperature. Apparatus: * Spotting Tile * Bunsen Burner * Beaker * Test Tube * Pipette * Amylase * Iodine * Stopwatch * Thermometer * Measuring cylinder Prediction: The amylase will break down the starch quicker according to how high the temperature is. This is because heat speeds up the rate of reaction. Heat gives molecules more energy, and causes them to move around faster and crash into other molecules harder. The amylase molecules will crash into more starch molecules in a shorter space of time increasing the chance of more successful collisions. When the amylase is heated too much, it will stop the amylase molecules working because they will die. The optimum temperature for enzymes is about 37°C because this is body temperature, and this will produce the best results. Variables: * Temperature - The changed will be changed during this experiment. I will be changing the temperature at 5°C intervals starting at 20°C. * Time - The time taken to break to break the starch down according to the temperature will be recorded. Method: ) The spotting tile will have the different temperatures of the amylase written on. 2) A small amount of iodine will be added to the spotting tile where
Biology Issue Report on GM Foods
A Level Biology – Unit 3 Issue Report Food Shortage March 2012 Course Code: AN03 Biology A Level 2009 Unit 3 - 6BIO3 -------------------------- ________________ Problem – Producing Enough Food for the World’s Growing Population Food shortages are not a new problem but they have become more widespread in recent years. Food riots took place in Haiti in 2008 following demonstrations over the rising price of food and India suffered drought due to the failure of monsoons in 2009 (1). Famine is a very real issue right now in Africa with the Sahel region of West Africa facing a “worsening food crisis (2)”. In the Horn of Africa (see fig 1) in 2011 tens of thousands of people died (estimates range between 50,000 and 100,000) from famine following a drought said to be the worst in 60 years (3). Climate change is one of the reasons behind the drought that triggered East Africa’s 2011 famine. As climate change is unlikely to be reversed in the near future, reduced rainfalls are expected to continue and a solution is needed to combat the diminished growth of crops and yield in arid, populated areas. The world population is nearly 7 billion at the moment and the United Nations estimates it will reach 9.3 billion by the middle of the century (4). The majority of the increase is expected to be in developing countries. The UN also states that food production must
The Industrial Application of Enzymes.
The Industrial Application of Enzymes. Enzymes are naturally occurring biological molecules found in all living organisms, plant, animal and microorganisms such as bacteria. All enzymes are proteins and, as with all proteins, are made up of a chain or polymer of amino acids held together by peptide bonds. This chain coils to form a specific three-dimensional globular shape, which, typically, means an enzyme will only work with one specific substrate. The purpose of an enzyme is to lower the activation energy required for biochemical reactions to take place. As a result a reaction catalysed by an enzyme will be much more efficient at breaking down a substrate into its products and consequently are used in industry for just this purpose. To obtain these enzymes scientist look mostly to naturally occurring microorganisms, as they are the most productive producers, are easy to handle, can be grown in huge tanks without light, and have a very high growth rate. This may sound all very new and scientific but microorganisms have been used for brewing, baking and alcohol production long before anybody knew of the existence of enzymes. One of the earliest references can be found in Homer's Greek poems dating from about 800 BC where he mentions the use of enzymes in the production of cheese. The starch industry has been using enzymes too for many years in the production of
The Human Genome Project
Amira Nicola January, 2001 The Human Genome Project The Human Genome project is a scientific research effort to analyse the DNA of human beings and that of several other types of organism. The project began in the United States in 1990 under the sponsorship of the U.S. Department of Energy and the National Institutes of Health. It was scheduled to be completed in 15 years. The project's goal is to identify the location of every human gene and to determine each gene's precise chemical structure in order to understand its function in health and disease. In the nucleus of every cell in the human body, there are 23 pairs of chromosomes, each of which is composed of several genes. Genes are discrete stretches of nucleotides that carry the information the cell uses to make proteins. The most important component of a chromosome is the single continuous molecule of DNA. This double-stranded molecule, which is shaped as a double helix, is composed of linked chemical compounds known as nucleotides. Each nucleotide consists of three parts: a sugar known as deoxyribose, a phosphate compound, and any one of four bases-adenine, thymine, guanine, or cytosine. These parts are linked together so that the sugar and the phosphate form the two parallel sides of the DNA ladder. This double-helical structure of the DNA molecule was discovered Watson and Crick in 1953, for
