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GCSE: Green Plants as Organisms

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  • Marked by Teachers essays 56
  • Peer Reviewed essays 13
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  1. Marked by a teacher

    Biology Lab Report. Does light intensity affect the rate of photosynthesis?

    4 star(s)

    Apparatus: 7 boiling tubes, 7 rubber stopper, 1 black paper, capillary tube, lamp Materials: Pond weed, fresh sodium bicarbonate indicator Method: 1. CO2 was blown into some fresh bicarbonate indicator until it turns to red, which used for experiment. 2. The test tubes are set up like in the diagram 1 and placed at varying distances from the light source. For the control experiment, put in a dark place with no light. 3. The time taken for bicarbonate indicator in each test tube to turn from deep red to purple is taken and recorded.

    • Word count: 652
  2. Marked by a teacher

    Use of a redox indicator to show dehydrogenase activity.

    4 star(s)

    Leave for several minutes to reach the temperature of the water bath. 3. Mix the yeast suspension and TTC solution together and return the test tube to the water bath. Start the stopwatch immediately. 4. Observe carefully and note the time taken for any colour changes to develop. 5. Repeat this procedure at a range of suitable temperatures, for example 20?C, 40?C and 50?C. Results and discussion: The yeast suspension and TTC solution were placed in the water bath before mixing together because the contents of both test tubes need to be at the same temperature as the water bath.

    • Word count: 968
  3. Marked by a teacher

    Human Influences On the Environment.

    4 star(s)

    As forests are destroyed in this way, habitiats are removed from the animals living in them, therefore the biodiversity decreases. Forests also hold a big role in the water cycle as they release back the water that falls on them through transpiration. If trees are removed this may reduce the amount of water vapour that returns to the air, and may reduce rainfall either locally or in nearby regions which could inevitibly lead to drought. Trees also intercept the rain , lack of interception means that the water will not be slowed down on its journey to the ground.

    • Word count: 656
  4. Marked by a teacher

    Effect of different substrates on fermentation by Yeast.

    4 star(s)

    We do not know what yeast can do, we know that it can break down glucose, but we do not know if it can break down starch into glucose to release carbon dioxide. So this experiment should help me to see what yeast can do. Plan: Collect and set the apparatus up as shown in the diagram. Heat the water to 40�C. Weigh out 1g of yeast, 2g of substrate and 3ml of water, and put in the test tube.

    • Word count: 775
  5. Marked by a teacher

    To investigate the factors which affect the rate of cooling of a hot object.

    4 star(s)

    I will repeat the experiment three times for each volume of water starting from 50ml. Fair test I will do all the experiments on the same day so that the weather conditions and surrounding temperature are the same for all of my results. This is because on another day the weather conditions would be different and would effect the surrounding temperature and therefore effect the rate the water in my experiment cooled. I will use the same measuring cylinder for all my experiments because another cylinder would measure the required amount slightly different, as they are all slightly different.

    • Word count: 957
  6. Marked by a teacher

    transpiration lab

    3 star(s)

    Transpiration also cools plants and enables mass flow of mineral nutrients from roots to shoots. Mass flow is caused by the decrease in hydrostatic (water) pressure in the upper parts of the plants due to the diffusion of water out of stomata into the atmosphere. Water is absorbed at the roots by osmosis, and any dissolved mineral nutrients travel with it through the xylem. The rate of transpiration is directly related to whether the stomata are open or closed. The amount of water lost by a plant depends on its size, along with the surrounding light intensity, temperature, humidity, wind speed, and soil water supply.

    • Word count: 751
  7. Marked by a teacher

    Testing Starch in a (Variegated) Leaf - Lab Report

    3 star(s)

    5. Place the leaf samples in the hot alcohol for about 5 minutes. 6. When the samples have decolourised, remove them from the hot alcohol using a glass rod. 7. Place the leaf samples back into the hot water for a few seconds; be careful as they could be fragile. 8. Remove the samples from the hot water and spread them out onto a white tile 9. Drop iodine reagent onto the leaf samples, you may need to wait for a few minutes 10.

    • Word count: 526
  8. Marked by a teacher

    Why does the colour leak out of cooked beetroot

    3 star(s)

    Prediction I predict that as the temperature increases, so will the colour of the beetroot. I predict this because of the knowledge I have on membrane structures. The red colour you see in beetroot, is a red dye that comes from pigments present in the beetroot called betalains, which are present in the cell vacuole. When beetroot is cooked, the temperature causes the pigments to leak through the cell membranes, which would not happen if it was not cooked. This happens because the increase in temperature damages the cell membrane, which causes the cytoplasm and other substances to leak out.

    • Word count: 713
  9. Marked by a teacher

    The Biological importance of water

    3 star(s)

    Because water can dissolve many substances, it can act as a transport medium. For example it can transport minerals to lakes and seas and can also remove metabolic wastes such as urea and ammonia in urine. Water has also a specific heat capacity. This means that a lot of heat energy is needed to change the state of water from liquid to gas (100�C to change from liquid to gas). This means that water does not change its temperature very easily. This is ideal in human and animal bodies as it allows the temperature of the body to stay maintained.

    • Word count: 641
  10. Marked by a teacher

    An experiment to measure the amount of oxygen bubbles given off in different strengths of sodium hydrogen carbonate

    3 star(s)

    Once these 3 minutes are over I will be taking readings on how many bubbles come out of the weed every 30 seconds and I will be taking ten readings. After I have took all these reading I will do the same again. But instead of the piece of pond weed being in water in will now be in 0.25% NaHCO3 and I will do the same leave it for 3 minutes so that the weed can get used to the solution and then I will start taking readings.

    • Word count: 923
  11. Marked by a teacher

    The effect of temperature change on the activity rate of Trypsin.

    3 star(s)

    A water bath was used to control the temperature of the mixture. Hot water from a kettle was used to heat up the Trypsin and milk mix, and ice was added to the water bath to cool it down when necessary. Trypsin was added to the milk and see how long it took for the milk to become transparent. A piece of paper was placed behind the test tube with writing on it. When the writing was clearly readable, the elapsed time on the stopwatch was recorded.

    • Word count: 679
  12. Marked by a teacher

    How are aquatic invertebrates adapted for gas exchange?

    3 star(s)

    An example of an aquatic invertebrate with this adaptation is the stonefly nymph, which was located in deep areas of slow moving water as it can get the oxygen it needs through this form of gas exchange. There were also organisms that had a circulatory system meaning that the oxygen they need is quickly transported via the blood that has obtained the oxygen by diffusion. The surface area to volume ratio also contributes to the high oxygen levels taken in.

    • Word count: 877
  13. Marked by a teacher

    Experiment to find the relationship between the size of the surface area to volume ratio of a container and the rate heat is lost

    3 star(s)

    * The independent variable is the size of the container and therefore the surface area to volume ratio. * The dependant variable is the rate of heat loss measured by temperature and time taken. Hypothesis * I think that the rate of heat loss will increase with a larger surface area to volume ratio and decrease with a smaller surface area to volume ratio over a period of time. Also I think that the rate of heat loss will decrease over a period of time.

    • Word count: 773
  14. Marked by a teacher

    Design a practical experiment to investigate the effect of light wavelength on the rate of photosynthesis.

    3 star(s)

    * Hold the test tube horizontally and then turn it upside down so that the pondweed enters the jar and attach the test tube to the clamp. Ensure that it is held firmly and that it is steady for safety reasons. * Take one of the coloured filters and wrap it around the jar. Use sticky tape to keep it in place if necessary. * Shine the lamp light onto the jar; make sure that it reaches the pondweed, at 10cm distance in each experiment so that the intensity of light will remain the same so that the results obtained are valid.

    • Word count: 681
  15. Marked by a teacher

    Factors Affecting the Rate of Photosynthesis

    3 star(s)

    The plant on which the theory and prediction will be tested will be Canadian pondweed. Aim: The aim of this experiment is to investigate how light intensity affects the rate of photosynthesis in Canadian pondweed. Variables: VARIABLE TYPE OF VARIABLE HOW MONITORED Light intensity Independent The distance between the plant and the light source will be carefully measured with a ruler Concentration of carbon dioxide Control The water will be saturated with sodium hydrocarbonate to ensure no change Temperature Control The room temperature will be constantly monitored using a thermometer Moisture Control The humidity of the classroom will be kept constant throughout Section of plant Control The same section of plant will be used for each observation Time Control A stopwatch will be used to ensure that each observation is only one minute No.

    • Word count: 852
  16. Marked by a teacher

    Determine the effect that temperature has on the rate of diffusion of food coloring in water.

    They are controlled by measuring out the amounts of each until they reach a set quantity. Therefore there is not too much or too little of the water or food coloring, which could cause an irregularity in the results. The water temperature is another controlled variable. The temperature of the water could vary, and has an effect on the rate of diffusion, which would therefore create uncertainty in the results, but it can be regulated by using a thermometer so that this does not happen.

    • Word count: 851
  17. Peer reviewed

    Water is a molecule composed of two elements of hydrogen covalently bonded with one element of oxygen

    5 star(s)

    The hydrogen bonds also allow water to have high surface tension. This happens because, although one hydrogen bond is relatively weak, when many of these bonds are formed between two molecules it causes the bonds to be sufficiently strong and quite stable. Hydrogen bonding also influences cohesion, the clinging of a water molecule to itself or adhesion, the clinging of a molecule to another molecule. Water is known as the "solvent for life" or the "universal solvent". Water is a good natural solvent because it exits in the liquid state in its natural habitat.

    • Word count: 750
  18. Peer reviewed

    Transpiration stream

    4 star(s)

    Root hair cells have a high surface area to volume ratio to efficiently absorb water. As water enters root hair cells, it has three routes for it travel along symplastic pathway, apoplastic pathway and vacuolar pathway. In the symplastic pathway water crosses the cellular membrane of root hairs and enters the cytoplasm of the cell, it travels between connecting cells through the plasmodesmata, this process occurs due to diffusion of water molecules from high concentration to low concentration. However the process is quite slow.

    • Word count: 951
  19. Peer reviewed

    Osmosis Coursework

    3 star(s)

    The process of diffusion is how we can smell an open bottle of perfume from the other side of the room. Perfume Particles Air Eventually these two types of particles will mix to become evenly concentrated about the room. Osmosis is similar, in a way that water molecules move through a semi-permeable membrane, to where water is least concentrated from where it is most concentrated.

    • Word count: 344
  20. Free essay

    The Affects of Light Intensity on the Rate of Photosynthesis

    3 star(s)

    3. Fill the test tube with water, and put the plant in the tube. 4. Make sure that the plant, which was put in the test tube fully, sinks in the water. 5. You need to wait two minutes before you can start counting the oxygen bubbles. 6. Make sure that you use the same plant for every experiment. 7. Make sure that the temperature is the same, for accurate readings. 8. As soon as the two minutes is over, you start the oxygen bubbles. 9. After the second five minutes are over, turn on of the lamps on, and wait for wait another two minutes.

    • Word count: 699
  21. Peer reviewed

    Photosynthesis Simulation

    3 star(s)

    30 seconds 1 9 30 20 2 9 30 22 3 9 30 26 4 9 30 30 5 9 30 33 6 9 30 34 Experiments Carbon Dioxide Concentration Time to taken to measure the oxygen bubbles in seconds Number of Oxygen bubbles Produced every 30 seconds 1 10 30 21 2 10 30 23 3 10 30 26 4 10 30 27 5 10 30 31 6 10 30 32 Variables: Independent: in this investigation two factors will be changes, carbon dioxide concentration and light intensity.

    • Word count: 552
  22. Peer reviewed

    an evaluation of the impact of glaciation on human activity

    3 star(s)

    The development of Sima has affected the flow of water that flows to the falls. In the summer the discharge of water was 12 meters per second so it is a spectacular site. This second example is a negative. This negative is to do with the increasing and improved roads that had to be built. The transport rout have been increased and improved because when Sima was being built you can't just have one single road you have to have lots of roads connected to each other like the a and b roads we have in Norfolk.

    • Word count: 857
  23. Free essay

    How Plants Produce Food

    Broad to give a large surface area for absorbing sunlight 2. Flat and thin with air spaces between cells to allow gases to circulate between cells easily 3. They contain large numbers of chloroplasts to trap sunlight energy 4. They have networks of veins to allow water to reach all parts of the plant 5. They are thin and flexible to allow them to bend rather than break Limiting factors Anything that slows photosynthesis is a limiting factor, since plants need carbon dioxide and light and require warmth for reactions to occur these can all be limiting factors.

    • Word count: 794
  24. The amount of sunlight there is affects how much starch is there in the leaf so I think the leaf with sunlight will have starch but the one without will not have any starch

    Materials (Apparatus): 1.2 plants 2. Plastic bag 3. Beaker 4. Test tube 5. Lighter 6. Bunsen burner 7. Tripod stand 8. Wire gauze 9. Thermometer 10.Alcohol 11.Water 12.Iodine 13.Dropper Diagram Method Use two identical plants and put one of them with a lamp. 1. Cover one plant with black plastic bag. 2. Wait for several days. 3. Prepare all the materials needed for the experiment 4. Set up the equipments. 5. Take one leaf from the both plants. 6. Put the beaker filled with hot water on the wire gauze. 7. Turn the valve to open. 8. Light the lighter.

    • Word count: 660
  25. Mung bean lab report - examining the effect of light on growth.

    Now place one bottle in an entirely dark environment, and the other in a generally light environment. After a week, gather the two bottles and remove the mung bean sprouts from each bottle. Record the height of each mung bean sprout, and calculate the average height of the sprouts that grew in the dark environment and the average height of the sprouts that grew in the light environment.

    • Word count: 461

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