What is DNA?
DNA DNA, otherwise known as deoxyribonucleic acid has changed our lives, including our perception of life, by both scientists and the average person. Science has developed dramatically due to the discovery of DNA. DNA was first discovered by the Swiss physician Friedrich Miescher and Gregor Mendel who, in 1869, discovered a microscopic substance in the pus of discarded surgical bandages. As it resided in the nuclei of cells, he called it "nuclein". In 1919 this discovery was followed by Phoebus Levene's identification of the base, sugar and phosphate nucleotide unit. Levene suggested that DNA consisted of a string of nucleotide units linked together through the phosphate groups. However, Levene thought the chain was short and the bases repeated in a fixed order. In 1937 William Astbury produced the first X-ray diffraction patterns that showed that DNA had a regular structure. In 1943, Oswald Theodore Avery discovered that traits of the "smooth" form of the Pneumococcus could be transferred to the "rough" form of the same bacteria by mixing killed "smooth" bacteria with the live "rough" form. Avery, along with coworkers Colin MacLeod and Maclyn McCarty, identified DNA as this transforming principle.DNA's role in heredity was confirmed in 1953, when Alfred Hershey and Martha Chase in the Hershey-Chase experiment showed that DNA is the genetic material of the T2 phage. In
The relative importance of factors that cause coronary heart disease
The relative importance of factors that cause coronary heart disease. There are many economical, environmental and genetic factors, which contribute to heart diseases. In this section, the factors will be discussed in terms of importance. Firstly coronary heart diseases result in myocardial infarctions or heart attacks. A myocardial infarction takes place when the blood supply to part of the heart muscle (myocardium) is cut down or prevented. This occurs when one of the coronary arteries supplying the blood to the heart becomes blocked due to a build up of deposits. These will eventually tear a rupture, causing a blood clot to form, which blocks the artery leading to a heart attack. One major economical factor contributing to coronary heart diseases is smoking. Over half of Britain indulges in more than five cigarettes a day. This increases the risks of arteriosclerosis. Arteriosclerosis refers to the hardening or narrowing of the coronary arteries. The arteries supply the blood that carries oxygen and nutrients to the heart. However, if they become blocked by arthrosclerosis, they are unable to deliver a certain amount of blood to the heart muscle. This can result in angina and heart failures due to weakening heart muscle. What does the smoke do ??????????????? From the journal of the American medical association. Artherosclerosis causes myocardial
Investigate the effect of altitude training on the density of blood.
An Investigation to find out the Effect of Altitude Training on the Density Mock Blood Rikin Patel Candidate Number- 1110 Centre Number- 63255 Aim The aim of this coursework was to investigate the effect of altitude training on the density of blood. Introduction Red blood cells, also known as Erythrocytes, are the most common type of blood cell and are a body's principal means of delivering oxygen to body tissues via the blood. The other type of blood cells in the blood are the white blood cells, which are actually immune cells. Red blood cells deliver oxygen via hemoglobin, a complex molecule containing four haem groups that temporarily link to oxygen molecules in the lungs and release the oxygen throughout the body. Hemoglobin also carries a waste product, carbon dioxide back from the tissues. Red blood cells consist of almost 90% hemoglobin; the heme is what gives blood its red colour. Myoglobin is similar to haemoglobin, but acts as a store for oxygen in muscle cells. Human red blood cells have a flattened ovate shape, depressed in the center. This shape is used because it optimizes for the exchange of oxygen with the surrounding cells. The cells are flexible so as to fit through tiny capillaries, where they release their oxygen. The diameter of a typical red blood cell is 6-8 µm. Below is a diagram of a red blood cell: Red blood cells are continuously being
Anaerobic Yeast Respiration
AT1 GCSE Practical Assessment Anaerobic Yeast Respiration Aim The aim of our experiment was to investigate one possible factor which could affect the rate of yeast respiration. Preliminary Work To provide an insight into our investigation, we researched some preliminary work which has previously been done. The preliminary researchers had altered both the temperature of the yeast, and the concentration of the glucose in the yeast. This was beneficial to our experiment because we could clearly see which of these two variants would give us the more interesting and fruitful experiment. The results of these preliminary experiments can be observed below: Temperature Of Yeast (ºC) Concentration of Glucose (ml) Time Left Respiring (minutes) CO2 Produced (ml) Control 21.0 .5 5.0 2.0 Increased Glucose 21.0 2.0 5.0 0.5 Increased Temperature 35.0 .5 5.0 6.2 From this table, we can clearly see that varying temperature will create more varied results. The more varied the results, the more we will be able to document in this write-up. From this preliminary work, we have decided to focus our experiment on alterations to the temperature. Prediction And Scientific Knowledge Our prediction is that as the temperature increases, the amount of yeast respiration occurring will also increase (hence the more carbon dioxide we will witness being given off). We can back
Biology Revision notes - Human Biology
Blood Pressure * Each time your heart contracts, it pumps blood into out arteries. * The blood needs to be under pressure so that it reaches all the parts of the body. A pulse - this is the recoiling of the arteries. Arteries are elasticised so that when blood is pumped, they expand and then contract. * The fitter you are, the lower your heart rate is because your heart is more efficient. * Pressure is created due to the blood pressing against the arteries and this is known as blood pressure. Blood pressure appears as a fraction and is measures in mmHg: Systolic: the heart contracts and pumps - The highest pressure on the arteries. Diastolic: the heart is relaxes and doesn't pump - The lowest pressure on the arteries. (mmHg - millimetres/mercury) Blood pressure is affected by: * Weight - being overweight increases the risk of high blood pressure * Exercise - strengthens heart muscles and keeps the heart fit * Diet - avoid salty and fatty foods * Temperature * Alcohol * Stress * Smoking - narrows blood vessels * Inheritance * Age - blood pressure increases with age * Underlying diseases High Blood Pressure Can cause: * An artery to burst * A stroke * A heart attack * Death High blood pressure means that the blood is pushing too hard against the artery walls. This damages the artery lining and allows fat and calcium to build up and form a plaque.
n this essay I will analysing what makes us happy and be going into vast depths as to what factors affect happiness and how certain chemicals, neurotransmitters and endorphins in the brain affects this procedure.What makes us happy
What Makes Us Happy By John Smith In this essay I will analysing what makes us happy and be going into vast depths as to what factors affect happiness and how certain chemicals, neurotransmitters and endorphins in the brain affects this procedure. Firstly I will be assessing the key question; what is happiness? We already know happiness has many forms, but what we will be going into, is what defines happiness and how do we find this out? In order to be happy, scientists have put the ideas of many generations of people together and have come with a theory that makes us happy. [1]To begin with we must have a goal, whereby we have a point of destination we consider worthy for our effort, this goal can be really small or really big. Secondly, we also need to live our life with enthusiasm, optimism and honesty. Only after reaching all these areas, can we become happy people. For reaching the superior more advanced forms of happiness, such as achieving satisfaction and contentment, we require taking paths leading to a meaningful life; a life where through having goals, we will find fulfilment. Generally the rule is that; the smaller the goal, the shorter the time of happiness, for example; buying a new car or a new home can give us a quick feeling of enjoyment but at the same time can quickly wear off, compared with these next factors. Health, family and friends,
Biology case study vaccination and MMR are they linked?
Kathrine Keller Case study: Does The MMR Vaccine cause autism? Contents: ? What is MMR? ? The Vaccination ? The Effects ? Autism ? The Autistic Spectrum ? Are They Linked? ? Arguments for and against. Vaccination Vaccination is the administration of antigenic material (the Vaccine) to produce immunity to a disease. Vaccines can prevent or ameliorate the effects of infection by a pathogen. It is considered to be the most effective and cost effective method of preventing infectious diseases. The material administrated can either be live, but weakened forms of pathogens such as bacteria or viruses, killed or inactivated forms of these pathogens, or purified material such as proteins. Smallpox was the first disease people tried to prevent by purposely inoculating themselves with other types of infections; smallpox inoculating themselves with fluid taken from mild cases of smallpox Vaccination is so named because the first vaccine was derived from a virus affecting cows\the relatively benign cowpox virus\which provides a degree of immunity to smallpox, a contagious and deadly disease. Vaccination efforts have been met with some controversy since their inception, on ethical, political, medical safety, religious, and other grounds. Early success and compulsion brought widespread acceptance and mass vaccination campaigns were undertaken which are credited with greatly
Design an Experiment to show how exercise can affect Heart Rate in Humans.
Design an Experiment to show how exercise can affect Heart Rate in Humans Results: The experiment was carried out but prior to this a few modifications were made. Modifications: The time allowed for recovery was not between 2 to 4 minutes as planned, instead it was 5 minutes. Instead of using the stairs to carry out the experiment, we used a bench. A metronome was not used during the experiment. Results: * It was hard to always get the resting heart rate before each exercise and so instead we waited until the resting heart rate was within 5 beats/minute of the original one. * The resting heart rate was measured for 30 seconds, three times before the exercise whereas the finishing heart rate was measured once for 15 seconds after the exercise. These were made up to beats/minute as shown in the table of results. Number of Step Ups Heart rate beats/minute Average heart rate (beats/minute) 2 3 4 5 0 74.00 79.00 66.30 59.60 72.00 70.18 5 94.00 90.70 72.00 N/A 93.00 87.43 0 11.33 00.00 83.00 20.00 05.30 03.93 5 24.00 N/A N/A N/A 09.30 16.65 20 31.67 14.70 08.00 36.60 19.30 22.05 25 N/A N/A N/A N/A 25.70 25.70 30 42.00 26.00 30.70 41.70 30.00 34.08 35 N/A N/A N/A N/A N/A N/A 40 51.33 33.30 45.00 43.70 33.30 41.33 The set of results in bold indicate my results to the experiment, whilst the other results
Ecstasy. For my Biology coursework, I have chosen the highly debated topic of whether or not to make ecstasy readily available
Page 2 - Glossary Page 3 - Introduction Page 3 - What Is Ectasy Page 3-4 - what does it do to you? Page 4-5 - Negative effects of MDMA Page 6 - The Law on MDMA Page 6-7 - Advantages and Disadvantages Page 7 - Conclusion Introduction For my Biology coursework, I have chosen the highly debated topic of whether or not to make ecstasy readily available. In the Following Pages I will describe both sides of the argument, for and against legalising ecstasy. From both sides I will give my opinion and justify it in the conclusion. What Is Ecstasy? Often called the Designer drug or Ecstasy is a Class A drug, frequently used by Clubbers to stay awake and energetic to literally "dance the night away". Normally in a tablet when ingested would give the user the desired effect for 3-6 hours after the 30 minute wait for the drug to kick in, followed by a gradual cool-down. On a more scientific term, Ecstasy is a synthetic chemical known as MDMA (methylenedioxy-n-methylamphetamine), or a combination of MDMA and MDA, which tend to have similar yet slightly different effects. The pure form of MDMA is a white crystalline powder. Although it's increasingly sold as powder in a plastic bag, it's traditionally and more widely available as either a pressed tablet, often branded with a symbol of some sort, or a capsule. The active oral dose of the drug is at least 75mgs, with most pills
Is the MMR vaccination safe?
Contents 2 Introduction 3 How does MMR give immunity? 4 How was MMR tested for safety? 5 What about the side effects? 6 Is there a link to autism and bowel disease? 7 Are separate vaccinations a better alternative? 0 What about mercury in vaccinations? 2 Are homeopathic substitutes an alternative? 1 Conclusion 2 Bibliography and References 3 Introduction MMR is a combined, live, attenuated vaccination which is given to children firstly at 13 months and then again as a booster at 3 years 4 months. It provides immunity against three diseases caused by viruses: measles, mumps and rubella. The diseases are all extremely unpleasant and can lead to serious complications (26). * Measles is an extremely infectious virus that usually causes high-fever, a rash and generally feeling unwell and will usually last for around five days in children, however sometimes longer in adults. One in every fifteen children will have serious complications, such as chest infections, fits and encephalitis (the swelling of the brain which can lead to brain damage). In extreme cases it can even be fatal. In 1987, the year before the MMR vaccination was brought into the UK 86,000 children caught measles and 16 died (1). * Mumps is another virus which also causes a fever, but also headaches, swollen glands in the face, neck and jaw and it can even result in permanent deafness and
