AS Edexcel Biology - Aim: To investigate the effect of caffeine on the heart rate of Daphnia (water fleas).

The effect of caffeine on heart rate. Aim: To investigate the effect of caffeine on the heart rate of Daphnia (water fleas). Background Information: Plants produce caffeine as an insecticide. Cocoa in South America, coffee in Africa and tea in Asia has all been used as 'pick-me-up' drinks containing caffeine. These days caffeine is used in a wide variety of soft drinks such as cola to enhance flavours. In addition to this, stimulant drinks such as Red Bull and Boost also carry high levels of caffeine as well as some weight-losing drugs and medicines such as Aspirin. IN humans, caffeine acts as a stimulant drug, causing increased amounts of stimulatory neurotransmitters to be released. At high levels of consumption caffeine has been linked to restlessness, insomnia and anxiety, causing raised stress and blood pressure. This can lead to heart and circulation problems. Hypothesis: I think that the Daphnia's heart rate will rapidly increase when the caffeine solution is added. This is because increases the amount of neurotransmitters released in the body so everything in the body will be working at a faster rate because of these. Planning: -Risk Assessment: 1. I need to be aware of weils disease so I will not come in to direct contact with the pond water and regularly wash my hands thoroughly throughout the experiment. 2. I will need to constantly keep my glassware on

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How can we prioritise species for conservation?

How can we prioritise species for conservation? Species becoming extinct: Species are facing various problems key to their survival such as destruction of animal habitats, damage to the natural environment of living things, for example trees are cut down to build homes, , Oil spills, acid rain and water pollution also add to the destruction of habitats. Moreover another cause for extinction is when animals are over-hunted for their meat, fur and other valuable parts.Another cause could be'when animals or plants arrive into a new habitat from a foreign place they sometimes introduce diseases that the native species can't fight. These "exotic" species can also prey on the native species'.[1] 'Ahmed Djoghlaf, head of the U.N. Convention on Biological Diversity stated that, "Extinction rates are rising by a factor of up to 1,000 above natural rates. Every hour, three species disappear. Every day, up to 150 species are lost. Every year, between 18,000 and 55,000 species become extinct. The cause: human activities." he said '.[2] Why conserve species: There are many advantages in conserving species not only the fact that we benefit from the diversity of animals and plants, as majority of our plants such as crops. Domestic animals are bred from wild relatives and can importantly benefit from the immense, scarcely tapped wild gene pools. Moreover Important requirements such as

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The Ways in Which Organisms Use ATP

The Ways in Which Organisms Use ATP ATP, the standard abbreviation of Adenosine-5'-triphosphate is a multifunctional nucleotide used in cells as a coenzyme, and can be best summarised as the standard energy currency universal to all organisms, and as such is utilised in metabolic (and other) processes throughout the cells of organisms, and is highly adapted to its function therein due to its high instability in aqueous solutions (eg tissue fluid) due to its easily hydrolysable phosphoannhydride bonds which when broken release a proportionally huge amount of energy. ATP is required during the contraction of skeletal muscle. ADP is released by the myosin head, this allows it to change shape thereby pulling the actin filament across itself. In order to detach the myosin molecule (for it to bind to a myosin binding site further along the actin) ATP binds to the myosin head, where it is hydrolysed to release ADP (which remains on the head) and inorganic phosphate. The energy released allows the myosin head to resume its normal position prior to the release of its ADP molecule, ready to bind further along the actin filament. Furthermore, ATP is utilised elsewhere within the same process, as it is used by carrier proteins on the membrane of the sarcoplasmic reticulum as a source of energy for the active transport of Ca2+ ions into the sarcoplasmic reticulum. It is when these

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Studying the Effect of Salt on Cress Germination

PLANNING Initial Method . Prepare 8 sterile Petri dishes with a perfectly fitting circle of cotton wool and filter paper, this will sit on top of the wool 2. A control dish must also be set up using the same steps as above 3. Weigh out 8 different salt measures, at 0.25, 0.5, 0.75, 1, 1.25, 1.5 and 1.75 4. Measure out 8, 50ml beakers of distilled water 5. Add the one measure of salt into a beaker (1 beaker for each weight) and stir until the salt is dissolved and cannot be seen 6. Add one drop of Plant nutrient growth (e.g. baby bio) to each solution 7. Add each solution into individual Petri dishes which were made up earlier on, make sure the cotton wool and filter paper are allowed a small amount of time to absorb as much water as possible before the next step 8. Add 10 Cress seeds to each of the 8 solutions and place the lid on the dish 9. Place the dishes in are area which is well lit by natural light 0. Check the dishes each day for a week and top up each dish with the same solution if it is becoming dry, add the same amount to each dish (record what you add) 1. Count and record the percentage I chose to carry out my method in this fashion as it gave me the best way to see which salt concentration had the biggest effect. I chose 8 solutions as it gives me a good range to monitor the salinity effects. The solutions are based on findings in earlier research

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descrive the biological importance of water

Making up between 70 and 95% of the mass of a cell, and covering over three quarters of the planets surface, water is one of the most important compounds on this planet. A single water molecule is made up of one oxygen atom covalently bonded to two hydrogen atoms. Covalent bonds are formed by sharing electrons between the outer shells of the oxygen and hydrogen atoms. However, what makes water so unique is the fact that it remains a liquid at room temperature. Many similar sized molecules (ammonia has a molecular mass equal to that of water-18) remain in their gaseous form at this temperature. The reasons for this unique thermal property are hydrogen bonds. The nucleus of an oxygen atom is larger and therefore contains many more protons that that of a hydrogen atom. Therefore, the electrons shared in the covalent bond between the oxygen and hydrogen atoms have a greater affinity for the oxygen atom than either hydrogen atom. This pulls the electrons closer to the oxygen atom and away from the hydrogen atoms resulting in the oxygen atom having a slightly negative charge and the hydrogen atoms developing slightly positive charges. These slight charges mean that when water molecules are close together, positively charged hydrogen atoms are attracted to the negatively charged oxygen atoms of a different water molecule. These attractions are known as hydrogen bonds and

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Find the relationship between amount of fat and amount of energy produced in different foods.

July 2001 Biology Coursework Year 10 Aim Find the relationship between amount of fat and amount of energy produced in different foods. Planning I am going to ignite different foods and see how much heat energy they give out. The food that causes the biggest amount of change in temperature will have the most amount of energy. However, calculations have to be carried out to create an average energy output per gram. Variables Independent Variables: This will change from food to food, thus giving me a range of different results. In this experiment it will be type of food. Dependant Variable: This is the amount of Energy per gram which can be calculated Controlled Variables: These are the things that will keep the same, in order to sustain a fair test. These are; * Apparatus * Type of boiling tube * Distance of boiling tube from Bunsen burner * Distance of food from boiling tube * Amount of time taken to move ignited food to boiling tube Fair Test It is essential that I keep it a fair test in order to sustain accurate results for comparison at the end. To ensure a fair test, I must keep the controlled variables for every test I do. The apparatus must all be kept the same because there may be some minor differences in insulation properties, or measure of accuracy between them. If this were to happen, it would prevent me from sustaining accurate results. The same

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Mitochondria & Chloroplast

Mitochondrion Chloroplast Similarity Main power source of the organism Double membrane, and intermembrane space. Contain DNA and RNA, which are involved with the synthesis of the membrane and enzyme proteins, when the organelles replicate during cell division. Contain 70s ribosomes. Contain similar enzymes and coenzymes Both are involved in ATP production via a proton gradient (across the thylakoid membrane of chloroplast, across the cristae for mitochondria) Have ATP-synthatases appearing as stalked particles (on the thylakoid membrane of chloroplast, on the cristae of mitochondria) Have electron transport chains (on the thylakoid membrane of chloroplast, on the cristae of mitochondria) Self-replicate. Differences found in both plants and animals. found in plants only Help in respiration help in photosynthesis. No pigment contains thylakoid membranes and pigment molecules Matrix Stroma Releases energy from sugar Requires energy (light) to make sugar (glucose) Complex substances (sugar) are broken down into simpler ones. Complex substances (sugar) are formed from simpler ones. Krebs cycle Calvin cycle Compare chloroplast and mitochondria Chloroplast can only be found in plants, while mitochondria can be found in not only plants but also in animals. They have some similarities like: they both have double membrane and intermembrane space; Contain

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Effect of nitrate concentration on the growth of Duckweeds

Introduction & Method At the beginning of the experiment, I put on a lab coat to protect myself from any danger that may occur. I made sure that all my equipments were clean and dry before I started, and I also measured the temperature of the room to confirm it was around room temperature. I then made sure that the ice cube tray was clean, I put a little label on one end of the tray to indicate my starting point row of the ice cube tray. I then made a little note to myself that the label indicated the row which will contain the 0.0% x 10-3 concentration of nitrate in the solution, and the rows onwards will contain the concentration of nitrogen in solution in ascending orders which I will use (0.0, 0.4, 0.8, 1.2, 1.6 and 2.4 % x 10-3). I Whilst pouring the solutions into a glass beaker I put on goggles and gloves to protect my eyes and hands from any contacts with the ammonium nitrate solution, as any contact can lead to irritation of the skin and eye. I poured 80-90cm3 of the 1st concentration which contained 0.0% x 10-3 of nitrate into a 100cm3 glass beaker. Next I used a clean syringe to measure out 25cm3 of the solution into the 1st well (near my label). The tray had 3 wells in a row and there were 6 rows, I repeatedly added 25 cm3 of the same ammonium nitrate solution into the remaining two wells of that row, so that I will obtain a result of three replicates with each

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An investigation into the effect of different sugars on respiration in yeast.

An investigation into the effect of different sugars on respiration in yeast. I am going to carry out an experiment, measuring the effect of different sugars on the respiration in yeast. In order to make a justified prediction I have researched different aspects of scientific knowledge, including respiration, yeast, sugar structure, enzymes and the collision theory. Glycolysis http://people.eku.edu/ritchisong/301notes1.htm Glycolysis is the splitting of a monosaccharide into two molecules of pyruvate. It takes part in the cytoplasm of a cell. Glycolysis begins with a monosaccharide with six carbon atoms, and ends with two molecules of pyruvate, each with three carbon atoms. For the first steps of glycolysis, energy from ATP is needed. However, energy is released in later steps to generate ATP. For every molecule of glucose, a net gain of two molecules of ATP is produced. The first stage of glycolysis is called phosphorylation, and results in hexose bisphosphate. This is shown in green on the above diagram. Hexose bisphosphate then breaks down into two molecules of triose phosphate. Hydrogen is removed from the triose phosphate and transferred to NAD to produce reduced NAD. These hydrogen's can then be used in oxidative phosphorylation to produce ATP. The end products of glycolysis are pyruvates, which still contains a lot of chemical potential energy. There are two

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Human Impact at Hastings Point Hastings Point is a small settlement on the coast just south of Tweed Heads and the NSW border.

Human Impact at Hastings Point Hastings Point is a small settlement on the coast just south of Tweed Heads and the NSW border. The effects have been largely felt at Hastings Point; human impact has been the cause of a great deal of damage to the abiotic and biotic factors of the surrounding environments such as the mangroves, rocky shore, and sand dunes. Hastings Point in the last 5 years to 10 years has been subject to a great deal of negative development, corrupt council members which has resulted in sewage flooding, dredging , sewage into the creek, mangrove degradation, destruction of rocky shore environments and longshore drift. The mangroves are being destroyed for development; the rocky shores are suffering from people taking too many sea urchins and oysters which destroy the wildlife. The sand dunes have been degraded by humans walking all over the dunes which wear them down and have caused them to be so far back from the water. (3), (1) and (4) One of the main concerns of human impact in Hastings Point is the residential and the commercial development that was approved by the corrupt council members and the development areas never underwent environmental checks which has led to a great deal of damage. When unchecked development happens and sewage pipes get cracked, eutrophication can happen and decaying algae can build up and cause the water which the sewage has

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