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
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
Using the streak plate method, compare the effect of two different brands of toothpaste on the growth of five different bacteria.
Biology experiment and investigation AIM: Using the streak plate method, compare the effect of two different brands of toothpaste on the growth of five different bacteria. HYPOTHESIS: The toothpaste containing higher levels of alcohol ingredients will have a greater effect of inhibition on the growth of bacteria than the toothpaste containing low levels of alcohol ingredients. This means that Colgate toothpaste will work better than the Sainsbury's own brand. METHOD: Wipe all work surface areas with 'Milton' using cotton wool, and wash hands with soap. Heat the inoculating loop in the Bunsen burner, on the blue flame, until the loop is red hot. Hold the loop upright to prevent any bacteria falling onto the hand. Leave the loop to cool for about ten seconds. Next, collect an agar plate with one bacteria already growing on the agar jelly. Remove the lid slightly from the plate containing the bacteria. Once the loop has cooled, insert it into the plate avoiding contact with the stem of the loop and the top of the plate. Wipe the loop over the slime until there is some in the loop. Using a prepared set agar plate, open the lid and swipe the loop over the set jelly without breaking it. First swipe the loop down the middle only a third of the way. Then swipe it across so the jelly is covered. Move the petri dish around whilst swiping the loop in a zigzag motion. Then
An investigation into whether varying light intensity at a stream affects the species diversity
An investigation into whether varying light intensity at a stream affects the species diversity Introduction: Foulden common has a variety of different habitats including grassland, young woodland, ponds, swamps, fenland, set-a-side and streams which enables a diverse range of organisms to be present in an area. Life for plants and animals in any medium is a constant struggle. Besides the physical environment, predators, parasites and other competitors that have to be contended with; but compared with a terrestrial existence, fresh water offers a relatively stable environment.i The small stream that runs a long the side of Foulden common is a tributary of the River Wissey, which eventually flows into the Great Ouse. The stream is spring fed so has a fairly high chalk content and so the waters are slightly alkaline. This is good for fresh water organisms, as the majority of fresh water organisms requite chalk (limestone: CaCO3) because they either have an exoskeleton or shell, both of which contain large amounts of chalk.ii The stream is quite shallow so available light can penetrate the bottom easily however light intensity levels vary considerably along the stream due to trees and bushes which are quite dense in places, spaced well apart in other places and totally absent in other regions. Aim: The aim of my investigation is to see whether varying light intensity
An investigation to determine the rate of bacterial growth in milk under different conditions.
An investigation to determine the rate of bacterial growth in milk under different conditions. Aim Fresh milk contains many microorganisms including the bacteria lactobacillus. Pasteurisation is the process where the milk is heated to a 72°c for 15 seconds, which kills most but not all of the bacteria. Under suitable conditions these bacteria reproduce rapidly. In anaerobic conditions i.e. when there is a lack of oxygen in the milk, the bacteria respire to produce lactic acid. The aim of the investigation is to determine the rate at which bacteria reproduce and therefore the rate at which they respire. This will enable us to determine how different sets of milk, react under different conditions. Although the rate of each bacterium does not change, as the density of bacteria increases through cell multiplication, the overall rate of oxygen uptake will increase. It is the rate of uptake that gives the colour changes in the rezararurin dye. The colour changes from blue to lilac to mauve to pink and finally it goes colourless. The rate of bacterial growth in the samples of milk is measured by the rate of microbial respiration, which is indicated by a fall in pH. A fall in pH is due the accumulation of lactic acid. The accumulation of lactic acid occurs when the density of bacteria increases through cell multiplication. As the density of bacteria increases the demand for
At the end of 1996 the IUCN announced that 33,730 species of plant are threatened with extinction. Should we care?
At the end of 1996 the IUCN announced that 33,730 species of plant are threatened with extinction. Should we care? "In one of our religious books it is written that the tree is like ten sons. It gives ten valuable things: oxygen, water, energy, food, clothes, timber, medicinal herbs, fodder flowers and shade." (Chipko leader, Sunderlal Bahaguna) Plants are essential to life on earth. They have the unique ability to fix carbon and synthesise all the primary metabolites essential for biosynthesis; for example, the 20 amino acids necessary for life. About 4 million species on earth rely upon the 380,000 species of plant (consisting of 250,000 higher plants) for survival (Green Inheritance, 1984). This number is not certain - estimates have been as low as 345,000 for species already named and described (Cronquist, 1981) and as high as 630,000 for species described plus an estimate of still unnamed and undescribed species (Schultes, 1972; Tippo and Stern, 1977). As described by Bahaguna, plants provide for us in many ways. On 8th April 1998 a major twenty-year study by botanists and conservationists was made public: on a worldwide scale one in every 8 plant species is presently facing extinction. The United States is the statistical leader among nations that harbours whole strains of soon-to-be-obliterated plants. According to the World Conservation Union's Red List,
Describe the main features of the environment occupied by Cyanobacteria including those that are from stromatolites.
Biology Part A: By Samantha Johnson 424 . Describe the main features of the environment occupied by Cyanobacteria including those that are from stromatolites. Cyanobacteria can be found in just about every imaginable environment on earth. Their primary inhabitations however are in wet or damp conditions, for example wet rocks, ponds, rainforests, streams and soil. They grow in water that is salty, salted or fresh and in cold or hot springs where no other micro algae can exist. Most marine forms of cyanobacteria grow along the shore where the washed up sea weed and other material sit (the zone between low and high tide) to obtain their nutrients. Cyanobacteria are also well-known for existing in freshwater localities with various trophic states. For example in Eutrophic lakes where water is murky and contains lots of plants to Oligotrophic lakes where water is very low in nutrients, which means that few algae grow there. This water is very clear. They have even been found on the fur of polar bears, giving them their greenish tinge. Other colonies of cyanobacteria live on wet rocks or sediments, sometimes forming what appears to look like mats over these rocks which survive there for millions of years. These are stromatolites. It is believed that cyanobacteria have been around for millions of years. Scientist have discovered that stromatolites are cyanobacteria in
C:Documents and SettingsIbrarMy DocumentsAntibiotic Resistant Bacteria.doc
Antibiotic Resistant Bacteria Bacteria's are one-celled organisms that were discovered in 1676 by Anthony Van Leeuwenhoek. Many people like to define bacteria as a germ, but in reality germs are a form of bacteria. Most bacteria are not harmful to one's body but helpful in ways no one expects. (Lietz 6) For example bacteria located in soil that is used to grow food by turning dead animals and plants into the rich, dark topsoil. (Leitz 7) They also make shelter for humans and animals. Bacteria are removed from ones teeth and body after brushing and bathing daily. (Leitz 59) It is always completely surrounding everyone daily and no matter where you go it will always be with you at all times. (Leitz 10) Dr. Alexander Fleming discovered penicillin in 1928 and this penicillin was made of mould and killed many types of germs and was later tested on rabbits and resulted in no harm to the rabbit. The problem was that no one was able to make large quantities of it so it was not used very often. (Leitz 45) After ten years of consistent growing of the penicillin it was finally able to be used on a few dying patients. (Leitz 46-47) In late 1942 penicillin actually began to sell and save lives all over. This form of mould known as penicillin is a form of an antibiotic. Antibiotics are a bacteria fighter that made from mould and fungi. It is a drug that became very common and worked
Ecosystem p2.doc
Ecosystem An ecosystem is generally an area within the natural environment in which physical (abiotic) factors of the environment, such as rocks and soil, function together along with interdependent (biotic) organisms, such as plants and animals, within the same habitat. Ecosystems can be permanent or temporary. Ecosystems usually form a number of food webs. At the base of an ecosystem, primary producers are actively converting solar energy into stored chemical energy. Photosynthesis is the process of converting solar energy, water, and carbon dioxide into carbohydrates and oxygen. The process occurs in two steps: first light energy is absorbed by chlorophyll to split a molecule of water releasing hydrogen and oxygen. The second step uses the energy to convert carbon dioxide to carbohydrates. Processes of Ecosystems This figure with the plants, zebra, lion, and so forth illustrates the two main ideas about how ecosystems function: ecosystems have energy flows and ecosystems cycle materials. These two processes are linked, but they are not quite the same Energy flows and material cycles. Energy enters the biological system as light energy, or photons, is transformed into chemical energy in organic molecules by cellular processes including photosynthesis and respiration, and ultimately is converted to heat energy. This energy is dissipated, meaning it is lost to the
Water has a number of unique properties, making it vital for organisms to survive. Without it, life would not ever have evolved. It provides surface tension, allowing many organisms to support themselves
Water Water is essential to life itself; with out water life on earth would not exist. Water is a major component of cells, typically forming between 70% and 95% of the mass of the cell. This means that we are made from approximately 80% water by mass and some soft bodied creatures such as jellyfish are made of up to 96% water. Water also provides an environment for organisms to live in, 75% of the earth is covered in water. The properties of water are essential for organisms to live in for a variety of reasons. The one that is most evident is its transparency. The fact that light can travel through it allowed marine life millions of years ago to develop a more sophisticated detection device other than sonar, sight. This is evident with many types of fish using visual effects to deter predators, like schools of fish in a large mass to make it seem as though they are bigger than they actually are. Coupled with the fact that light can travel through water, so can heat; which is essential for aquatic plants to photosynthesise. Water has a molecule of oxygen contained within it; this means that aquatic Organisms such as dogfish are able to extract that molecule for respiration using a series of vascularized gills. Water is kept flowing over these gills by a specialized pumping system. And it is due to the density of water, in comparison to air, that prevents the gills from
