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International Baccalaureate: Biology

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  • Marked by Teachers essays 11
  • Peer Reviewed essays 1
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  1. Marked by a teacher

    Biology: Lab report Germination

    4 star(s)

    seeds are placed in a hot environment, then their germination will be positively affected compared to cress seeds grown in a normal light environment because seeds Variables The independent variables in this experiment were the light and the temperature. We put some of the cress seeds under a bright light and others in a dark cupboard. As for the temperature, we put some cress seeds in a stove and others in a fridge. The dependent variable in this experiment is the germination.

    • Word count: 1944
  2. Marked by a teacher

    The effect of temperature on amylase activity

    4 star(s)

    After adding in iodine, when amylase breaking down starch, less and less starch will be present and the color of this solution will become lighter and lighter. Equipments � 0.1% Amylase 0.5 ml � 1% Starch 5ml � 10 Test tubes and rack � Iodine solution � Syringes � Marker pen � Electronic water bath set at 20, 30, 40, 50, 60 and 70�C with thermometers � Dropper � Thermometer � Beakers � Spot-plates � Stopwatch Controlled variables � Same temperature of amylase and starch solution This can ensure that amylase can react with starch solution in the same temperature,

    • Word count: 1232
  3. Marked by a teacher

    Effect of substrate concentration on catalase activity (Biology IA)

    3 star(s)

    * 4% Hydrogen Peroxide Solution (5cm3) * 3% Hydrogen Peroxide Solution (5cm3) * 2% Hydrogen Peroxide Solution (5cm3) * 1% Hydrogen Peroxide Solution (5cm3) * 0.5% Hydrogen Peroxide Solution (5cm3) * Coloured Liquid * Distilled Water * 3x 20cm3 Syringes * 1x U-Shaped Tube (manometer) * 1x Stopwatch * 1x Retort Stand with clamps * 1x Rubber Bung * 1x Tube * 1x Forceps * 1x Scalpel * 1x Ruler * 1x White tile * 4x Plastic Containers * 1x Safety Goggles * 1 pair of gloves Procedure 1. The chicken liver was cut into pieces each measuring approximately 1cm by 1cm by 1cm.

    • Word count: 1206
  4. Marked by a teacher

    The Roles of ATP

    3 star(s)

    As far as it is known every living thing uses ATP as its primary source of energy, from bacteria to plants. At any instant in time a cell in the human body can contain about one billion ATP molecules, but this amount is used up quite quickly and is normally recycled straight away in the mitochondria where chemiosmotic phosphorylation occurs. One way that ATP is used is for muscle contractions, when you are running, walking, even me typing this essay, your body is using ATP to move muscles for movement, but not only movement, but it isn't only used for

    • Word count: 1166
  5. Marked by a teacher


    3 star(s)

    The cups used for the solutes must be completely dry before adding the solutes in. The same potato must be used to obtain all potato chips, in order to keep the water potential of the potato. The experiment must occur at room temperature. The same balance must be used, to achieve accuracy in measuring the mass. Equipment List: - Stop Watch - Electronic Scale - 1 whole potato - Cork Borer - 1 Piece of paper towel (cut into 5 pieces)

    • Word count: 1975
  6. Marked by a teacher

    The effect of Pectinase Concentraton on the production of apple juice

    By using a range of concentrations (1-5%) there should be a notable change in the results to show its effect in the production of apple juice as its concentration increases. Dependent - The volume of apple juice (ml) The volume of apple juice is the effect the concentrations have on and will vary depending on the concentration used and only due to the concentration. Control - To keep the experiment fair and ensure that the results are accurate, the following factors need to be kept the same: * pH - Different enzymes work better in different pH conditions as they have their optimum pH which allows them to react at different rates.

    • Word count: 1397
  7. Peer reviewed

    Enzyme Coursework. Investigation to find the effect of substrate concentration on the rate of an enzyme controlled reaction

    5 star(s)

    The rate of an enzyme controlled reaction are mainly affected by: temperature, substrate concentration, enzyme concentration and pH. By increasing the substrate concentration, there is a higher chance of a substrate colliding with an enzyme and subsequently reacting (as there is simply more substrate moving around in the solution). Increasing the substrate concentration further will cause the rate of reaction to plateau when all of the enzymes' active sites are constantly in use - at which point the enzyme concentration can be considered a limiting factor.

    • Word count: 1640
  8. Heart Recoil IA. Aim To compare the recoil and subsequent elastic limit of a mammalian aorta and vena cava.

    Vena cava ((length with mass-length without mass)/ length without mass) x100 ((3.6-3.4)/3.4) x 100 5.8% Aorta ((3.8-3.3)/3.3) x100 15.2% Observations From observations, the walls of the aorta are clearly thicker and feel tougher than the vena cava. The aorta is also light in colour (light flesh pink) whilst the vena cava is a darker plum red. Analysis The first two tables of results above shows the elastic recoil of the vena cava and the aorta. It demonstrates as the length of the vena cava/aorta when the mass is put on and when the mass is removed to see if it has stretched. The mass increases down the table from no mass (0)

    • Word count: 1491
  9. Plant Cromatography Lab Report. How does the use of different colored leaves affect the amount of colour traveled within paper chromatography?

    Temperature Throughout the experiment, the four samples had a room temperature of 23 � 0.05. This is because the use of different temperatures throughout the experiment can have an effect on the colour observed within paper chromatography. Time All four chromatographs were placed within the test tubes at relatively similar times to ensure that there is an insignificant time difference between the four samples. Thus, this could reduce the percentage error within the experiment. I. Methods Materials & Apparatus * 4 Test tubes * Filter papers * Glass rod * Two disposable gloves * Graduated cylinder (50 ml)

    • Word count: 1037
  10. Biology Lab Report - Effects of Mouthwash on Oral Bacteria

    Mouthwash may also be used to help remove mucus and food particles deeper down in the throat. This experiment therefore aims to find out the effectiveness of mouthwash against oral bacteria. Mouthwash 'A' is 'Oral B - Natural Mint', an anti cavity mouthwash designed to prevent the occurrence of cavities in teeth. Mouthwash 'B' is 'Scope-Mint', is anti bacterial in nature. Mouthwash 'C' is 'Listerine-Cool Mint', is antiseptic. The last variable is distilled water, the control in the experiment. 1.

    • Word count: 1085
  11. Protein Digestion Design Lab. To detect the amount of protein molecules or short polypeptide chains in the cooked egg white for this experiment, the biuret reagent will be used.

    Every enzyme functions most effectively at a specific pH. For example, pepsin, the protein-digesting enzyme secreted by the cells of the stomach lining, functions optimally at a pH of 2, depending on the substance being digested. On the other hand, trypsin, a protein-splitting enzyme secreted by the pancreas, functions optimally in an alkaline medium at a pH of 8.5, depending on the substance being digested. Most intracellular enzymes have pH optima near neutrality and do not operate successfully in an acid or alkaline medium.

    • Word count: 1521
  12. Research Question: Which method of DNA extraction (using a centrifuge or not) will yield the most DNA, and which fruit (banana, papaya, or strawberry) contains the most DNA?

    extracted from each source Controlled variables: initial amount of fruit used in each trial, identical method of DNA extraction (aside from the use of centrifuge) Materials and Methods Equipment * 90% isopropyl alcohol * 100mL graduated cylinder * dishwashing soap solution * test tube rack * Test tubes for centrifuge * Centrifuge * 500mL beakers * Salt (NaCl) * pipets * coffee filters * fruits (papaya, strawberry, banana) * Plastic zip-lock bags * Electronic balance beam * Glass stirring rods Procedure 1.

    • Word count: 1065
  13. Experiment - Influencing the Rate of Photosynthesis with Light Intensity and Carbon Dioxide Concentration

    However, gradually temperature will decrease the rate of photosynthesis as the enzymes denature. Purpose and Hypothesis Purpose: To determine the affect of light intensity and carbon dioxide concentration on the rate of photosynthesis. Hypothesis: If the light intensity and amount of CO2 increases, then more oxygen bubbles will be produce because the rate of photosynthesis has increased. The rate of photosynthesis will increase because increased light intensity increase the energy chlorophyll absorbs, which then produces more productions including oxygen. The carbon dioxide concentration increase allows the enzymes to be saturated which also increases the rate of photosynthesis.

    • Word count: 1744
  14. Enzyme Lab. pothesis: If liver and potato tissue are tested for the amount of catalase and peroxidase, then it will show that liver tissue has more catalase than potato tissue has peroxidase.

    Placed the rubber stopper in the test tube. 8. Observed for 30 seconds, collected data, and recorded it in the data table. 9. Cleaned and dried the test tube and placed it back in the test tube rack. 10. Massed 2g of finely chopped potato tissue. 11. Measured 1 mL of 3% H2O2 and added it to the test tube. 12. Placed potato on the side of the test tube so that it was not touching the H2O2. 13.

    • Word count: 1151
  15. Osmosis Lab. What is the effect of concentration of blackcurrant squash on osmosis in chipped potatoes?

    This is because there is a higher concentration of water in the chipped potatoes. In other words, the water moves outside the potato chip through the permeable membrane since there is a higher solute concentration outside the potato chips. Variables Independent Dependent Control Blackcurrant Squash Concentration (%) Change in mass of chipped potatoes (g) Total amount of solution Size of chipped potatoes Type of blackcurrant Squash Distilled water Control of Variables We controlled the variables by keeping the same amount of solution using a measuring cylinder, same size of chipped potatoes using the ruler and same size of borer, the same type of blackcurrant squash and distilled water throughout the experiment for consistency and accuracy of data.

    • Word count: 1185
  16. Experiment to find the water potential of the cytoplasm of potato cell (Solanum tuberosum linnaeus

    strips/g (0.02g) % Change of mass of the potato (Solanum tuberosum linnaeus) strips/% 0.1 1 0.05 9.43 2 0.04 7.27 3 0.04 6.90 4 0.04 7.02 5 0.04 7.02 0.2 1 0.02 3.57 2 0.03 5.17 3 0.03 5.26 4 0.02 3.17 5 0.01 1.54 0.3 1 -0.01 -1.79 2 0.00 0.00 3 0.00 0.00 4 -0.01 -1.39 5 -0.01 -1.00 0.4 1 0.02 -3.23 2 -0.02 -3.03 3 -0.01 -1.00 4 -0.01 -1.82 5 -0.02 -3.33 0.5 1 -0.05 -8.20 2 -0.04 -6.56 3 -0.04 -5.71 4 -0.03 -5.00 5 -0.04 -6.67 X 100% = % change in mass Table 1.2 % Change in mass of the potato (Solanum tuberosum linnaeus)

    • Word count: 1840
  17. Biology lab. Observing plant and animal cells using the light microscope

    They zone tightly to each other. Each cell has a dense transparent cover (cell wall, which supports the form of the cell) with the more subtle areas - pores, which can be discerned only under high magnification, using them cell gets the nutrients and take out unwanted substances. The composition of membranes of plant cells is of special substances - cellulose, which gives them durability. Inside is a colorless viscous substance - cytoplasm. In the cytoplasm there is a small, dense nucleus (containing the genetic information), where we can see the nucleoli. Some cells do not have any nucleus, it means that they are already dead.

    • Word count: 1075
  18. Experiment. The dependence of the rate of photosynthesis on light intensity

    And if yes - how and to what extent? Research question How the light level may affect the release rate of oxygen during photosynthesis? Chemical studies of Lavoisier (1775, 1781) led to the conclusion that plants convert carbon dioxide into oxygen only in the presence of light. Light in photosynthesis plays a role not only catalyst, but also one of the reactants. A significant portion of the light energy used by plants during photosynthesis is stored as chemical potential energy in the products of photosynthesis.

    • Word count: 1096
  19. Osmosis Lab. Aim: To investigate the effects of different solute concentrations on osmosis, calculate water potential, and plant cell plasmolysis.

    Tomorrow, remove the potato cylinders from each solution and blot them with paper towel. Data Collection and Processing: For the experiment, data was taken from six different samples. We cut six of the same size potato cores and measured the mass. After we measured the temperature of each cup filled with water and the solutions. Five of the cups had a different amount of sucrose solution and the sixth cup was just filled with water and its constant. Placing the potato wedges in the different solutions, the osmosis began to work and I left the cups sealed for a day.

    • Word count: 1056
  20. Lab Report: Coral Reef Ecosystem - LIT Technique. This experiment aims to assess the sessile benthic community of coral reefs in around the Pramuka Island (one of the islands amongst the Thousand Islands located in Indonesia)

    29.5 - 30.2 Sand, dead corals 30.2 - 30.8 Soft coral (Simularia sp) 30.8 - 31.2 CB 31.2 - 31.7 Sand, dead corals 31.7 - 32.8 CSM 32.8 - 33.25 Sand, dead corals 33.25 - 33.55 CB 33.55 - 34.2 Sand, dead corals 34.2 - 34.5 CB 34.5 - 38.4 Soft coral (Simularia sp) 38.4 - 38.7 Sand, dead corals 38.7 - 39 CE 39 - 40.3 CSM 40.3 - 41.6 Sand, dead corals 41.6 - 41.8 CM 41.8 - 42.8 CSM 42.8 - 43.7 CE 43.7 - 45 CB Processed Data: SITE 1 CORAL TYPE CALCULATION CSM CM Soft coral (simularia sp)

    • Word count: 1504
  21. Potato IA Lab. This experiment tested osmosis when dealing with different concentrations of salt on the outside of the membrane.

    If there is a higher concentration of salt on the outside of the membrane, then water will move across the membrane to the outside in order to reduce the concentration of salt. Variables: Independent variable: Salt concentration Dependent variable: Weight of potato cores Constants: Amount of distilled water Water temperature Size of potato cores Type of potatoes Type of salt Room temperature Apparatus: - 5 Red potatoes - 1500 mL distilled water - 15 Plastic cups - Table salt - 500 mL beaker - 100 mL graduated cylinder - 1 cm diameter corer - Stir plate - Permanent marker -

    • Word count: 1457
  22. Surface Area to Volume Ratio Simulation Experiment. The comparison between surface area : volume ratio and time taken for agar blocks to decolourise.

    Agar blocks Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Average 1 3723.00 3634.80 3624.00 2425.20 3655.20 3332.20 2 2889.00 2895.60 3460.80 2357.40 2459.00 2812.36 3 2160.60 2114.4 2487.00 2238.00 2126.80 2225.24 4 1769.40 1866.00 1920.00 1638.00 1683.00 1784.28 5 1444.20 1324.20 1518.00 1590.00 1419.40 1459.12 Table 1.3: The comparison between surface area : volume ratio and time taken for agar blocks to decolourise. Agar blocks Surface area : Volume ratio Averaged time taken for agar blocks to decolourise/s (�0.01s)

    • Word count: 1622
  23. Research Question: Does the duration of exercise have an increased effect on a persons heart rate?

    - The Type of exercise will be restricted to Jumping Jack. This is done because different exercises are more taxing than others, by at least each individual will be performing the same degree of activity. - Each person will record their base-level heart rate by exercising for 0 seconds. - The Temperature of the room will remain constant by allowing all individuals to exercise in the same room. Materials: -Clock Procedure: 1. Gather at least 10 students for exercise and 1 other student to watch time 2.

    • Word count: 1935
  24. How Does Exercises And Tea Affect Heart Rate And Blood Pressure rate as well.

    I will be testing these factors by two different kind of experiment firstly after drinking a cup of tea, and secondly after doing a hard exercise. FIRST EXPERIMENT (TEA): Materials: -Tea bag - boiling water at 100 Celsius - 275 ml glass cup - Stethoscope. -Sphygmomanometer �5 mmHg -Stopwatch �0.01 sec. General Information: Blood pressure and Pulse rate must be measured with a beat Per Minute (BPM) and the pulse rate with Millimetre of Mercury Variables: a) Independent: amount of tea. b) Dependent: -The results of different values of blood pressure and pulse rates (-Pulse Rate �1 BPM) I reached.

    • Word count: 1628
  25. Catalase lab. This intent of this lab is to investigate how the factors of different pH levels and how they affect catalyze activity on the decomposition of hydrogen peroxide.

    Planning (a) Research Question- What affect does the change in pH level of hydrogen peroxide (??2??2) have on the amount of height of the bubbles (??2 liberated) when hydrogen peroxide (??2??2) reacts with a catalase enzyme after one minute? Hypothesis- When the pH level of the hydrogen peroxide (??2??2) is too high or too low from neutral pH (pH of 7), the oxygen (??2) liberated from the catalase activity will be decrease. Variables- Variables Units Range Independent Variable pH level of hydrogen peroxide (H2O2)??2??2 solution Hg In pH pH levels of 2, 4, 6, 8, 10 Dependent Variable Height of the foam (oxygen (??2)

    • Word count: 1867

IB Biology is the study of living organisms. The four basic concepts which run through the course are: evolution, equilibrium within systems, universality versus diversity, and structure and function. These concepts give the student a strong foundation upon which other detailed knowledge can be built. You will also be completing a significant amount of practical work and an experimental approach is strongly emphasised.

Assessment is both externally and internally organised. The external examinations are a mixture of multiple-choice, short answer and extended answer tests.The extended answer examinations require you express yourself in a concise and scientific manner and some great examples of these IB Biology essays can be found on Marked by Teachers. Science can bring enormous benefits to societies and you will be encouraged to become a responsible and ethically minded scientist.


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