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GCSE: Humans as Organisms

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  • Marked by Teachers essays 43
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  1. Marked by a teacher

    Biology Revision notes - Human Biology

    5 star(s)

    The coronary arteries are very important because they supply blood to and from the heart. When heart muscle cells don't get enough oxygen they begin to die. This is a heart attack. A high systolic pressure is more dangerous than a high diastolic pressure because that is when there is most pressure on the arteries and if it's even higher, they could burst. A high diastolic pressure is also dangerous because that is when your heart should be resting, so if it's still going really hard, then the heart isn't getting enough rest and it is constantly under pressure.

    • Word count: 8676
  2. Marked by a teacher

    Should the MMR vaccination be made compulsory in the UK?

    5 star(s)

    Its most visible effect is the current drop in the uptake of the vaccine. MMR vaccinations have fallen to a rate of 82%, the lowest figure since 1989 [5]. This is important, because there are few alternative ways of ensuring that an epidemic of any of the three diseases, with the severe side effects that they can bring, is prevented and over the last few years Britain has seen large outbreaks of measles. Currently, vaccinations are voluntary in the UK and a prescription from a doctor is required to authorise the vaccination, but a change in policy could ensure higher vaccination rates.

    • Word count: 4193
  3. Marked by a teacher

    Artificial Cardiac Pacemakers

    5 star(s)

    This then causes the heart to contract, which results in blood being pumped around the body. This results in a single heart beat. Normally, the sinus node (natural pacemaker) sends 60-100 electrical impulses per minute to the heart4. Therefore the average heart beat for a person is 60-100 beats per minute. An individual's heart rate is going to fluctuate during the day, depending on different activities that person is doing. During exercise, the quantity of blood (and oxygen) required from the muscles increases.

    • Word count: 3972
  4. Marked by a teacher

    Biology notes

    5 star(s)

    * Solvent = liquid in which the particles are dissolved eg water. * Solute and solvent molecules move around randomly. * Solutes can move into and out of cells by diffusion and osmosis. Diffusion * Diffusion is the spreading of the particles of a gas, or of any substance in solution, resulting in a net movement from a region where they are of a higher concentration. * Oxygen required for respiration passes through cell membranes by diffusion. * The greater the difference in concentration, the faster the rate of diffusion. Osmosis * Water often moves across boundaries by osmosis.

    • Word count: 5059
  5. Marked by a teacher

    Is the MMR vaccination safe?

    5 star(s)

    In the year before the vaccine was introduced 43 babies a year were born in the UK with CRS(8). The mothers of babies with CRS normally catch it from their own or friends children. Since the vaccination's introduction in 1988 it has almost eliminated all three diseases. In Finland, the rate of measles has fallen from around 15,000 cases every year in 1988, before the introduction of the MMR vaccination programme, to zero cases in 1996. For mumps and rubella, the number of cases was a few thousands, but fell sharply after the introduction of MMR to a few hundreds and since 1997 there have been no cases of any of the viruses (2).

    • Word count: 5390
  6. Marked by a teacher

    Myocardial infarction

    5 star(s)

    Introduction Sixteen New Zealanders die each day, or one person every 90 . minutes, as a result of Coronary Artery Disease ( Hay, 2004 ). Acute Coronary Syndrome accounts for approximately 7 million deaths annually in the world. http://www.dpcweb.com/documents/news&views/issue2_2005/troponin-i.html "In New Zealand, Cardiovascular Disease ( heart, stroke and blood vessel disease ) was the leading cause of death, accounting for 40% of all deaths in 2000 ". 22% of those deaths were from coronary heart disease ( CHD ) with admissions to public hospitals totalling 29,456 in 2000 - 2001 ( 59% men and 41% women ).

    • Word count: 3908
  7. Marked by a teacher

    Science in the news- should cannabis be legal?

    4 star(s)

    Argument For These advantages are reasonable enough to argue for the legalisation of Cannabis. Cannabis can have a relaxing effect on people, as well as more social effects, which include Talkativeness, Cheerfulness, and Greater appreciation of sound and colour. (ref 2) I find this fact very reliable as it is stated by the BBC on their website www.bbc.co.uk I trust the BBC because of their professionalism, as they are much respected world wide because of all of the work they do, especially in the media.

    • Word count: 1348
  8. Marked by a teacher

    biology diabetes work

    4 star(s)

    Most of the people who have this type of diabetes are overweight. People with type 2 diabetes may be able to control their condition by losing weight through diet and exercise. They may also need to inject insulin or take medicine along with continuing to follow a healthy program of diet and exercise. Although type 2 diabetes commonly occurs in adults, an increasing number of children and teenagers who are overweight are also developing type 2 diabetes. This shows you just how important it is to have a healthy and well-balanced diet as well as a healthy lifestyle.

    • Word count: 2141
  9. Marked by a teacher

    Biology case study vaccination and MMR are they linked?

    4 star(s)

    The MMR Vaccination The MMR vaccine is a mixture of three live viruses, administered via injection for immunization against measles, mumps and rubella. It is generally administered to children around the age of one year, with a booster dose before starting school. It is widely used around the world; since introduction of its earliest versions in the 1970s, over 500 million doses have been used in over 60 countries. As with all vaccinations, long-term effects and efficacy are subject to continuing study.

    • Word count: 1765
  10. Marked by a teacher

    science case study

    4 star(s)

    Sometimes it can be fatal. * Mumps - this can cause meningitis, which can result in deafness. It may cause inflammation of the pancreas, leading to pain, nausea and vomiting. In boys it can damage the testicles and cause infertility. * Rubella - this is also known as German measles and is usually a minor illness. However, it's harmful to pregnant women. If you become infected during the first 10 weeks of pregnancy, it's very likely to cause problems in your unborn baby. These include heart damage, blindness, deafness and brain damage. It can also lead to miscarriage.

    • Word count: 1227
  11. Marked by a teacher

    The effect of different sugar substrates on the rate of yeast respiration

    4 star(s)

    In s****l reproduction, two cells fuse to form a diploid cell which then forms haploid spores by meiosis. Below is the equation for the aerobic respiration of yeast using glucose as an example, Glucose + Oxygen Carbon Dioxide + Water When the yeast is mixed with sugar it soon starts to respire. The yeast uses sugar and oxygen to produce carbon dioxide, water and energy by aerobic respiration. Glucose is phosphorylated, eventually producing two molecules of pyruvate. The process is called Glycolysis and takes place in the cytoplasm of cells. The presence of oxygen enables pyruvate to enter the mitochondrial matrix where it is oxidatively decarboxylated to make acetyl CoA by the dehydrogenase.

    • Word count: 4943
  12. Marked by a teacher

    An investigation into the effect of temperature on the rate of respiration in yeast

    4 star(s)

    As can be seen from the diagram, if the enzyme changes shape, the active site (the area where the substrate reacts) would no longer be able to fit the substrate. This would mean the enzyme would lose its effect; the substrate would not break down. This happens when the temperature is too high; the process is called "denaturing". When an enzyme reaches a certain temperature, it will have so much energy that it is de-shaped; it is "denatured". This diagram shows how a denatured enzyme will not work: The enzymes will hardly work at very low temperatures (they wont be active).

    • Word count: 2409
  13. Marked by a teacher

    Design an Experiment to show how exercise can affect Heart Rate in Humans.

    4 star(s)

    132.00 131.67 25 N/A N/A N/A N/A 30 140.00 141.00 145.00 142.00 35 N/A N/A N/A N/A 40 150.00 151.00 153.00 151.33 * The values highlighted in red were identified as anomalous in this table of results as they did not fit with the general trend of the results. These results were therefore omitted from the calculation for the averages. * The values of averages in the table are noted to 2 decimal places. Graph: The following graph was made to show the relationships between the average heart rate (beats/minute)

    • Word count: 2960
  14. Marked by a teacher

    The circulatory system.

    4 star(s)

    The heart 1. The blood enters the right-hand atrium. The blood is deoxygenated. 2. The right atrium pumps this blood into the right ventricle. 3. The right ventricle pumps the blood through the pulmonary artery to the lungs where oxygen is picked up. 4. The blood then returns to the left atrium through the pulmonary vein. 5. The left atrium pumps the blood into the left ventricle. The blood leaves here through the aorta to be distributed to the rest of the body.

    • Word count: 746
  15. Marked by a teacher

    Investigate the effect of altitude training on the density of blood.

    4 star(s)

    The hemoglobin is eventually excreted. Haemoglobin is the substance that transports oxygen and is found in the red blood cells. It is an iron-containing oxygen-transport in the red cells of the blood in humans. The molecule is mostly protein mutations in the gene for the haemoglobin protein result in the hereditary diseases sickle cell anaemia, as well as a group of diverse but rare diseases called hemoglobinopathies. At the centre of the molecule is a heterocyclic ring, which is a ring like back bone whose atoms are not all of the same element.

    • Word count: 4715
  16. Marked by a teacher

    Does Caffeine Affect Heart Rate?

    4 star(s)

    In high doses they can make you anxious, irritable and even psychotic. Caffeine perks you up by stimulating the heart and suppressing the effect of adenosine, one of the brains inhibitory chemicals. FAIR TEST: It is important that this experiment is kept to a fair test because if it isn't then the results will not be accurate, as I need them to get accurate results. I can get the experiments to be a fair test by trying to keep the Daphnia that we use to be the same one so that it the cardiac output of the Daphnia isn't different.

    • Word count: 1757
  17. Marked by a teacher

    Investigation into the density of mock blood.

    4 star(s)

    The maximum amount of oxygen with which haemoglobin can combine is said to be 100%, in this case the haemoglobin molecule is said to be saturated. At low partial pressures of oxygen, the percentage saturation of haemoglobin is very low. At high partial pressures of oxygen, the percentage saturation of haemoglobin is very high. Therefore in the capillary in the lungs, where the partial pressure is high, the haemoglobin will be 95-97% saturated. However in an actively respiring muscle, where the partial pressure of oxygen is low, the haemoglobin will be about 20-25% saturated with oxygen, that is the haemoglobin is carrying only a quarter of the oxygen that it is capable of carrying.

    • Word count: 2527
  18. Marked by a teacher

    Explain how arteries, veins, and capillaries are adapted for their functions. Describe what happens in coronary heart disease and explain how lifestyle may contribute to the development of this disease.

    4 star(s)

    This is effectively a double circulatory system as both ventricles pump blood and both atria receive blood simultaneously. The pulmonary system starts in the right ventricle where deoxygenated blood is pumped via the pulmonary artery to the lungs. Here it is reoxygenated and returned to the left atrium via the pulmonary vein. The systemic system pumps the oxygenated blood from the left ventricle via the aorta. The aorta branches into the carotid artery that serves the head and forelimbs, the hepatic artery the liver, the mesenteric artery the gut, and the renal artery the kidneys and lower limbs.

    • Word count: 1756
  19. Marked by a teacher

    Anaerobic Yeast Respiration

    4 star(s)

    We can back this prediction up with scientific knowledge, to assure its accuracy. As the heat of the water bath surrounding the yeast solution increases, the particles of carbon dioxide and glucose will move around more, and at a faster pace, hence is it more likely that some particles will collide and create a reaction. The particles will move around at a greater pace because there is excess energy produced by the increasing heat which needs to be vented in some way, and as movement is the simplest way.

    • Word count: 1264
  20. Marked by a teacher

    The Effects of Exercise on the Heart Rate

    4 star(s)

    There may then be a period when the muscles are working anaerobically, without oxygen. A waste substance of aerobic respiration is pyruvic acid; this is then converted into CO . But when anaerobic respiration is taking place the pyruvic acid is oxidised and is converted into lactic acid. The lactic acid would begin to build up from the oxidation of pyruvic acid in muscles. Muscular contractions would become difficult because lactic acid prevents the conversion of energy quickly. If the muscles continued to work anaerobically then muscular cramps would begin until finally they would not work at all.

    • Word count: 3358
  21. Marked by a teacher

    The Advantages and Disadvatages of Designer Babies

    3 star(s)

    Fertility Institutes proudly claimed that this was just the icing to the cake, and therefore plan to offer pretty much any conceivable customization as technology now makes it available. Opponents however condone the company for shattering moral and ethical boundaries. Like it or not, the era of designer babies is officially here and there is no going back. For decades a technology called pre-implantation genetic diagnosis, or also known as PGD, has enabled IVF clinics to screen embryos for numerous of potentially and often deadly diseases before the embryo is implanted into the mother?s womb.

    • Word count: 3658
  22. Marked by a teacher

    Enzymes Essay; Enzymes used in the Baby Food industry

    3 star(s)

    This is because the baby's digestive system is not strong enough to break down the large molecules of proteins in regular food. This also helps as it lets the large protein molecules to partly break down into amino acids. Enzymes are known to be biological catalysts; these enzymes consist of various types of proteins that work to drive the chemical reaction for a specific action or nutrient.

    • Word count: 412
  23. Marked by a teacher

    In this case study I will discuss the cases for and against the statement: The MMR vaccine could be linked to autism.

    3 star(s)

    You become immune to the disease. This is called immunisation. Shortly after the MMR vaccine was introduced there was a speculation that it could be linked to autism. In this case study I will discuss the cases for and against the statement: The MMR vaccine could be linked to autism. (1) What is MMR? MMR stands for Measles, Mumps and Rubella. Measles is a virus that can be spread by water droplets produced by coughs and sneezes. A rash appears after four days of having caught the disease. There are also other symptoms that may occur earlier than four days.

    • Word count: 1575
  24. Marked by a teacher

    OCR GCSE Case Study: Is MMR Safe?

    3 star(s)

    Measles is probably the worst, most fatal illness out of the three included in the vaccine. Measles is an infection of the respiratory system caused by a virus. It can lead to chest infections, fits and brain damage. Before the vaccine was introduced, about 90 children in the UK died each year due to measles. Mumps is a viral disease caused by the mumps virus. Before the development of the vaccine, it was a common childhood disease worldwide, and is still a major threat in third world countries. It causes swelling around the jaw and can lead to viral meningitis, deafness and swelling of the testicles and ovaries.

    • Word count: 1195
  25. Marked by a teacher

    Biology Data Analysis-Does heart rate effect reaction time?

    3 star(s)

    I predict that if we have a faster pulse rate, the better our reaction times will be. If you think, when your heart is working faster, you have more blood flowing around your body...including voulentary muscles, there would also be more oxegen. A faster heart rate also produces aderenaline. The Experiment In this experiment, 8 girls were tested and 4 boys, 12 people in total. Lesson time was used to carry out this experiment. And we had the classroom and any equiptment in the classroom. Firstly we recorded our test buddy's reaction times when they had a resting heart rate.

    • Word count: 1694

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