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.
Investigating the effect of Sucrose Concentration on the Rate of Osmosis in Potato Chips.
G.C.S.E Science: Investigating the effect of Sucrose Concentration on the Rate of Osmosis in Potato Chips Sophie Chapman 25th March 2003 Aim: I shall carry out a sequence of independent experiments in order to investigate how the rate of osmosis in a potato chip is affected when the concentration of sucrose solution is varied. Apparatus: 300ml Sucrose concentration 300ml Distilled Water 2 x 100ml beaker 1 x 100ml Measuring Cylinder 1 x Potatoes 1 x Forceps (Tweezers) 1 x Scalpel Chipper 12 x Polystyrene Cups 1 x Stop - clock Tissues 12 x Sticky Labels 1 x Pen 1 x Calculator 1 x Ruler (measuring mm) 1 x Balance 1 x Polythene Food Bag Cardboard Apparatus Justification: To complete the experiment, I need 300ml distilled water and 300ml sucrose concentration as I intend to carry out 12 tests (using 6 different volumes but each shall be repeated twice) each using a 100ml of liquid whether it be pure water, pure sucrose concentration or a solution containing both. I will detail about the exact volumes of water and sucrose concentration that I want to use in each experiment, in the written procedure. I shall use varied amounts of sucrose solution for each test in order to adjust the concentration - a solution containing more sucrose has a greater concentration than a solution containing less sucrose solution. It is essential that the concentrations be
An Investigation into the Effects that Different Light Intensities have on the Speed of Woodlice:
An Investigation into the Effects that Different Light Intensities have on the Speed of Woodlice: Introduction: Woodlice are one of the easiest terrestrial arthropods to obtain in large numbers throughout the year. Porcellio scaber, the most common species is not difficult to identify with the naked eye, and is large enough to be handled without employing special techniques. Their behaviour is relatively simple yet providing perfect examples of kinesis and taxis. i A species, which shows taxis, can orient the direction of their movement with respect to the source of an external stimulus whilst kinesis is a steady-state dependence of the movement velocity on the stimulus intensity.iii Thus it is clear that kinesis will be the important response in my investigation as I am not concerned with the stimulus direction. Woodlice lack a waxy cuticle on their exoskeleton and have a high surface area to volume ratio. This means that they are prone to desiccation. As a result, much of their behaviour is concerned with reducing water loss. Woodlice will therefore tend to congregate in more humid, cooler and darker regions where their water loss will be lower.ii Although light does not affect the physiological state of woodlice in the same way as humidity and temperature, it plays a very important part in woodlice behaviour. Woodlice have a negative photokinesis- they move faster as
Research question - Is using dogs for work ethical?
Dog behaviour CDA Introduction There are many ways that animals are connected to our lives. Some of us have them as pets, and even people who don't have a pet still have products (such as medicine) that have been tested on them. According to a website called 'The vegetarian site' very well known companies such as 'Max factor', 'Vaseline' & even 'Kleenex' have products that are animal tested. Some people protest that animal testing is not ethical because of the pain the animals have to endure for our benefit, but others argue that a lot of the medicine we have now wouldn't of existed if it hadn't of been so. A lot of argument has also gone into the concept of conditioning. We condition animals and even people without noticing we are doing it. Dogs are trained to sniff drugs in an airport and even children have a daily bed time that they are used to. So when J.B Watson sprung a debate about ethics when he conditioned Little Albert (who was just a baby at the time) to be afraid of rats and other things that looked similar, he had opened a controversy. Does there have to be pain to gain? Or will we ever find out if a dog thinks it is ethical for itself to be entered into a race? We were studying at school the behaviour and characteristics of animals that are similar to those of human beings alongside the ethics to support the current world debates & trends. This particular
How does the concentration of a sucrose solution affect the rate of Osmosis in Potato Cells?
Jennie Lace 10c How does the concentration of a sucrose solution affect the Rate of Osmosis in Potato Cells? PLAN I have chosen to investigate how the rate of osmosis taking place in potato cylinders varies when I change the concentration of the surrounding sucrose solution. I will vary the concentration of sucrose in the solution, and carry out various measurements on the potato cylinders before and after the experiment, to see what affect changing the concentration has had. I predict that with the lowest concentration of sucrose, the potato will increase in mass, because of water moving into the cells. The percentage increase will then get smaller each time I increase the concentration of sucrose in the solution. At some point, the mass of the potato will not increase, and will be the same as it was before (when there is no net flow of water particles in or out of the potato cells). After this, the mass of the potato will start to decrease as I keep on increasing the concentration of the sucrose solution. At some point the potato cylinders will lose all the water that they are able to, and the percentage mass loss will stop decreasing. This is what I expect the graph of my results to look like: Osmosis is the movement of water particles from a weak solution (a hypotonic solution) to a strong solution (a hypertonic solution. It happens through a selectively
To determine the water potential of a potato tuber cell using varying salt solution.
Aim To determine the water potential of a potato tuber cell using varying salt solution. Introduction Osmosis is the diffusion of water molecules from a region where it has higher water potential to a region where it has lower water potential through a partially permeable membrane1. As osmosis is a type of diffusion the same things that affect diffusion have an effect on osmosis some of theses things are: * The concentration gradient - the more the difference in molecules on one side of the membrane compared to the other, the greater the number of molecules passing through the membrane and therefore the faster the rate of diffusion2. * The surface area - the larger the area the quicker the rate of diffusion * The size of the diffusing particles - the smaller the particle the quicker the rate and polar molecules diffuse faster than non-polar ones3. * The temperature - the higher the temperature the more kinetic energy the particles have and so the faster they move. From the diagram4 we can see the process of osmosis in a simple expression. On the right side there is pure water, which has the maximum water potential of 0. Water potential is the pressure created by water. As you can see from the diagram the pure water is pushing its way through the semi permeable membrane at a high pressure. This is its water potential. Water potential is measured in kilopascals (kPa)
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
Biology Coursework - Osmosis
Contents Pg. 3 - Plan: Introduction & Aims Pg. 4 - Plan: Osmosis Research Pg. 6 - Plan: Potato Cell Research Pg. 8 - Plan: Variables & Non-Variables Pg. 9 - Plan: Proposed Method Pg. 10 - Plan: Hypothesis Pg. 11 - Preliminary: Introduction and Aim Pg. 12 - Preliminary: Variable and Controlled Variables Pg. 13 - Preliminary: Method Pg. 15 - Preliminary: Results Pg. 17 - Preliminary: Graphs Pg. 18 - Preliminary: Conclusion & Evaluation Pg. 19 - Experiment: Equipment Pg. 20 - Experiment: Safety Pg. 21 - Experiment: Method Pg. 22 - Results: Table Plan: Introduction & Aims In this coursework, I will be studying the process of Osmosis. To do so I will carry out an experiment, this will look at the effects of Osmosis on chips of potato in a sucrose solution. The experiment will involve placing identical potato chips into different sucrose solutions with varying concentrations, after 45 minutes, I will take the potato chips out of the solutions and weigh them, changes in mass would indicate Osmotic activity. My aim is as follows: "To investigate the effect of varying concentrations of sucrose solution on the amount of osmotic activity between the solution and a potato chips, identical in size" I hope that by the end of the investigation, I will have a better understanding of osmosis and a conclusion that demonstrates that knowledge. Plan: Osmosis Research To
Rates of Reaction
Introduction In this investigation I am investigating the reaction between hydrochloric acid and calcium carbonate (known as limestone). The rate of reaction is basically the speed a reaction takes place- meaning how long it occurs for. Chemical reactions only occur when reacting particles collide with each other with sufficient energy to react. The minimum amount of energy that causes them to react is called the activation energy - simply because it activates the reaction. There are many variables that need to be taken under consideration when measuring the rate of reaction. These can include catalysts, surface area, temperature or concentration of the liquid. In this case the dependant variable is the concentration of the liquid. These variables can either decrease or increase the rate of reaction. Theoretical Background When a reaction takes place it has to overcome a minimum energy barrier known as the Activation Energy. If the particles collide with less energy than the activation energy then nothing worth noting happens. "You won't get a reaction unless the particles collide with a certain minimum energy called the activation energy of the reaction." (Taken from www.chemguide.co.uk). Only those collisions, which have energies equal to or greater than the activation energy result in a reaction taking place. The reason why collisions have to overcome the
Biology notes
AQA GCSE Biology Unit 2 Summary Notes 2.1 Animal and Plant Cells Cells * Cells are the smallest unit of life. * All living things are made of cells. * Most human cells, like most other animal cells, have the following parts: o nucleus o cytoplasm o cell membrane o mitochondria o ribosomes * Plant cells also have: o cell wall o chloroplasts o permanent vacuole What do these structures do? * Nucleus - controls the activities of the cell. * Cytoplasm - where most of the chemical reactions take place. * Cell membrane - controls the passage of substances in and out of the cell. * Mitochondria - where most energy is released in respiration. * Ribosomes - where protein synthesis occurs. * Cell wall - strengthens plant cells. * Chloroplasts - absorb light energy to make food in plant cells. * Permanent vacuole - filled with cell sap in plant cells. Other facts: * The chemical reactions inside cells are controlled by enzymes. Examples: o Enzymes for respiration are in the mitochondria. o Enzymes for photosynthesis are in the chloroplasts. o Enzymes for protein synthesis are on the ribosomes. * Cells may be specialised to carry out a particular function. Examples: Tissues, organs and systems * A tissue is a group of similar cells carrying out a particular function. * An organ is a group of different tissues carrying out a particular function. *
