An Experiment to determine Water Potential in Potato Tissue.
An Experiment to determine Water Potential in Potato Tissue Introduction Osmosis is the movement of water molecules move from a region of high water concentration (high water potential) to a region of low water concentration (low water potential). The water molecules also move through a partially permeable membrane. Osmosis affects the shape of plant cells. When a plant cell is in a lower water potential (highly concentrated solution), water from the plant cell moves out and therefore it becomes flaccid, and this is when the cell membrane of the plant cell shrinks. When a plant cell is in a solution which has higher water potential, the water moves into the cell and therefore it becomes turgid, this is when the cell membrane expands. In both cases, it is only the cell membrane that changes its shape. The cell wall always keeps its shape. The mass of plant cells change as well. This is because water is moved into or out of the plant cell and therefore a change occurs to its mass. At equilibrium (when the solution's water potential and the plant cell's water potential are the same) there will be no movement of water. Therefore the shape and the mass of plant cell would stay the same. The tendency of water molecules to move from one place to another is measured as the water potential, which is represented by the sign ?. It is a Greek letter for Psi. The water molecules can
Does Traffic Pollution Cause Asthma?
Introduction In my case study, I aim to research whether there is a correlation between asthma and traffic pollution. I will show this by identifying traffic pollution, asthma and its causes. I will present this through graphs and text which include, how asthma is caused and if traffic pollution has an effect on it or not. I will study a range of articles and arguments whether people believe that traffic pollution is one of the causes of asthma. Page 1 Asthma and the statistics for it in children Page 2 Which gases come out of cars Page 3 Correlation graphs Page 4 Is there a correlation between traffic pollution and asthma Page 5 Reasons why there would be Page 6 Reasons why there wouldn't be Page 7 Conclusion References Asthma Symptoms of asthma occur when a person with asthma comes into contact with something that irritates airways. Airways will then tighten, swell and become narrower. Sticky mucus and phlegm builds up in the airway lining making them even more narrow and irritated. The airways are small tubes that carry air to and from your lungs. This diagram shows a normal air tube and then an inflamed one. STATISTICS FOR ASTHMA IN CHILDREN * In 2005, 27 children (14 and under) died from asthma * 42% of people with asthma say that traffic fumes stop them from walking and shopping in congested areas * One in ten children have asthma and it is
GAS EXCHANGE
Gas Exchange Gas exchange supplies oxygen for cellular respiration and disposes of carbon dioxide: an overview • Gas exchange is the uptake of molecular oxygen (O2) from the environment and the discharge of carbon dioxide (CO2) to the environment. • The source of oxygen, the respiratory medium, is air for terrestrial animals and water for aquatic animals. • The atmosphere is about 21% O2 (by volume). • Dissolved oxygen levels in lakes, oceans, and other bodies of water vary considerably, but they are always much less than an equivalent volume of air. • The part of an animal where gases are exchanged with the environment is the respiratory surface. • Movements of CO2 and O2 across the respiratory surface occurs entirely by diffusion. • The rate of diffusion is proportional to the surface area across which diffusion occurs, and inversely proportional to the square of the distance through which molecules must move. • Therefore, respiratory surfaces tend to be thin and have large areas, maximizing the rate of gas exchange. • In addition, the respiratory surface of terrestrial and aquatic animals are moist to maintain the cell membranes and thus gases must first dissolve in water. • Because the respiratory surface must supply O2 and expel CO2 for the entire body, the structure of a respiratory surface depends mainly on the size of the organism,
Genetic fingerprinting
25/11/09 Genetic Finger Printing ) Genetic fingerprinting is a method which identifies people using only samples of their DNA. It produces very precise results and is used a lot in forensic science and paternity testing. A small sample of hair, blood or other tissue is given. This sample will contain white blood cells which are broken open using detergent. Then enzymes cuts the DNA making it smaller and this is added to agarose gel. Finally the pieces of DNA receive either coloured or radioactive probes. The pattern is recorded and produces the DNA fingerprint. 2) Genetic fingerprinting Is used for : * Diagnosing Genetic disease - Mutations in the DNA can show inherited diseases and predicts tendency to some diseases. If particular diseases run in a family, it can help predict if individuals or their unborn children are at risk as well. * Forensic science - To match crime suspects to samples of skin, hair, blood or saliva found. * Paternity testing - The DNA from the mother, child and alleged father are compared. The DNA matching DNA between the mother and the child are ignored and the left over DNA from the father are observed and can determine who is the father. * Organ Donor - To match DNA samples between two people and ensure that they are compatible. * Study of animal - Scientists use the DNA to measure the amount of genetic variation between different species
A2 Biology Coursework -Investigation into the effect of different concentrations of antibiotics on the growth of bacteria
Biology Coursework Aim: My aim is to investigate the effect of different concentrations of antibiotics on the growth of bacteria. Hypothesis: I predict that as the concentration of the antibiotics increases the bacteria growth decreases Null Hypothesis There is no link between the concentration of antibiotics and the effects it has on the growth of the bacteria Theory Antibiotics work in 4 ways, which are listed below: . Cell Membrane Disruption - This involves making the cell fully permeable which results in substances moving into it causing it to burst and so kills the bacteria 2. Inhibiting Nucleic Acid Synthesis - This method doesn't kill the bacteria off but keeps the growth level static. The bacteria isn't able to replicate its DNA and so no binary fission occurs, causing the growth level to become static 3. Inhibiting Cell Wall Synthesis - This is where an antibiotic inhibits the enzyme required to form cross links within the cell wall and as a result the bacteria looses its structure and is unable to function properly . 4. Inhibiting mRNA Translation - This is where the Translation part of protein synthesis is inhibited by binding across the bacterial ribosome meaning proteins and enzymes the bacteria it requires isn't made and so dies. Having said how antibiotics work above, it is logical to presume that the higher the concentration of antibiotics
The Economic Impact of the Use of Enzymes in Industry.
The Economic Impact of the Use of Enzymes in Industry Enzymes are very precise protein molecules with a high specificity which are used to catalyse chemical reactions by lowering the activation energy required for the reaction to take place. It is these properties of being able to break down substances easily and bind specifically to certain chemicals that make enzymes very useful in many industries and practices throughout the world. In addition to this enzymes are not used up in experiments so products of processes are not contaminated with enzyme which could be a problem. This essay explains 3 uses of enzymes, in industry and food, diagnosing and analysing, and treating disease, explaining the function and advantages of enzyme use in each example. An enzyme is a biological catalyst, used for speeding up chemical reactions in cells. They are all proteins; and work by making and breaking bonds. They are not used up during a reaction, and a good catalyst can accelerate a reaction by up to 10 times. When they do this, they reduce the activation energy needed for the reaction, which means that the rate of reaction is increased. For example, catalase increases the decomposition rate of hydrogen peroxide into water and oxygen. It lowers the activation energy of the reaction from 75 kJ per mol to 21 kJ per mol. One molecule of catalase can break 40 million
Heat loss from animals
Saira Hamid 1CM BIOLOGY COURSEWORK Heat loss from animals Investigation: To investigate heat loss from animals. Aim: To find out how body size affects the rate of heat loss. Background: The way heat is transferred from the animal to its surroundings can be done in three ways, convection, conduction and radiation. Convection: hot gases expand and become less dense, therefore rise and are replaced by cooler gases this is called the cooling affect. This happens in animals with less body coverings. Where the environmental temperature has a greater difference to that of the animal. Conduction: is when molecules transfer heat vibrating and passing on the vibration. This occurs when the animal is in direct contact with a surface, so the vibration molecules are passed from the animals' feet to the surface it is in contact with. Radiation: there are no molecules are involved in this type of heat transfer, so therefore the heat is transferred by waves. Some animals such as the polar bear, which lives in arctic conditions, has had to adapt in its environment, because it has to decrease the amount of heat loss and instead conserve the heat. Just like the polar bear other animals such as the camel have had to adapt to live in the desert conditions so therefore it needs to increase the amount of heat loss. Both these animals have had to adapt to the environment that they live
How the Mass of Plant Tissue is Affected by a Range of Water Concentrations
How the Mass of Plant Tissue is Affected by a Range of Water Concentrations I will make my investigation fair test by making sure that only the independent variable which is the water concentration changes. There are several control variables which I must ensure I keep the same: * Light * Temperature * Oxygen level in the water * Carbon dioxide level in the water * Size and type of chip I will make sure these remain the same throughout the experiment by: Light: I will carry out the experiment in the same place in the room. Temperature: I will carry out the experiment in the same position in the room. Oxygen level in the water and carbon dioxide level in the water: These are not likely to change much, but I will get the water from the same source. Size and type of chip: I will cut the chips all to the same size and get them from the same source. Prediction I predict that the lower the concentration of water that is in the test tube, the more mass the potato chip will lose. Reasons for Prediction I think that that the end mass will be higher when there is a higher concentration of water because the plant tissue will take in more water. Therefore the more water in the tissue the higher the mass will be. The plant tissue will absorb the water through a process called Osmosis. Osmosis is the movement of water molecules from an area of high concentration to an area
Cloning means making a living thing from another living thing such as a plant or animal. The process uses the genes of the first so they both have identical DNA.
TRANSLATION PRACTICE -1st year CLONING Cloning means making a living thing from another living thing such as a plant or animal. The process uses the genes of the first so they both have identical DNA. Cloning isn't new. Nature has been doing it for billions of years with plants. Things like potatoes and grass send out shoots which can grow into a whole new plant. If you grow a plant from a cutting it's a type of cloning. And identical twins are naturally-occurring clones of each other even though they're genetically different from their parents. In the last few decades scientists have been trying to clone animals. They transplant DNA (the gene pattern which makes living things unique) from the cell of one animal into the cell of another which has had its DNA taken out. Now scientists in America have announced that they have created a clone of a human embryo. In 1997 Dolly the sheep became the first ever cloned mammal. Scientists in Scotland used a new type of technique. When Dolly was born months later, it had taken 276 tries to get it right. Since Dolly, cows, pigs, monkeys, rodents, cats, mules, horses and dogs have been cloned. Animals or plants with special qualities could be mass produced to help in the manufacture of important drugs. You could replace pets which have died or even repopulate endangered or extinct species. In 2001 the first
Investigation to find out how light intensity effects the rate of photosynthesis
Investigation to find out how light intensity effects the rate of photosynthesis Contents * Introduction * Aim * Hypothesis * Variables * Precaution * Fair Testing * Apparatus * Method * Diagram for Method * Results * Analysis of Results and Graphs * Conclusion * Evaluation * Errors, limitations and Improvements Introduction Flowering plants, like all living organisms, need a supply of food. They need it as a source of energy in respiration and they need it as raw material for growth and repair. Animals and most micro- organisms get their food in an organic form: they eat products from other organisms (such as fruit and eggs) or, nowadays, the organic substances made in laboratories and factories. Animals and the microorganisms that do this are called consumers. Due to the flowering plants can make their own organic food from simple inorganic substances and an outside source of energy, they are called producers. Once the producers have made their food they use it in the same way as the consumers do as a source of energy and as raw material for growth and repair Photosynthesis The simple inorganic substances from which flowering plants make their food are carbon dioxide (CO2) and water (H2O). These contain no energy that a flowering plant can use an outside source of energy is needed to combine them into a compound that the plant can use as food. The source
