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International Baccalaureate: Biology

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  1. Biology HL IA - Transpiration lab report

    Variables: the rate of transpiration (the amount of H2O taken, mm) (dependent variable) will be altered by reducing the area of leaves (cm2) (independent variable). Table 1 Controlled variables. Controlled variable Units Possible effect Method to keep it constant Light intensity m Would alter the rate of transpiration Windows will be covered, only the same day light lamps will be turned on in the laboratory Temperature �C Changes, shown by special apparatus, would be reduced by conditioning the room Humidity % Each change in humidity will be shown by special apparatus and then conditioning will be made Air movement m/s

    • Word count: 1725
  2. Cellular Respiration

    Pi 2 + 2 NADH + 2 H+ + 2 ATP + 2 H2O GLYCOLYSIS Step 1: Phosporylation: Step 2: Splitting 6C sugar to 2 x 3C sugars: Step 3: Energy release: - Glucose diphosphate will link back to glucose phosphate --> good thing is that it can be a inhibitor. - Glucose, glucose phosphate, fructose phosphate, fructose diphosphate, dhap and pgal, 2 pgal. Biochem of aerobic respiration - Aerobic respiration occurs within most living cells and is the process by which food molecules are broken down, in the presence of oxygen to produce energy - Glucose +oxygen --> carbon

    • Word count: 677
  3. Influence of yeast concentration on rate of cellular respiration

    was reached. The acceptable change in the temperature was � 0.05 �C. The amount of CO2 produced was kept the same through having the same distance of 5 cm in the manometer tube, as only the same amount of CO2 would move through that distance. The time has been measured since agreed level in the manometer tube was reached, in order to avoid the paralax effect. Mass of sugar and solution was controlled by using weighting machine and by keeping the same mass of each solution for different yeast concentration. Apparatus: * Yeast (20g)

    • Word count: 1471
  4. polygenic inheritance lab report

    177 9 18.95 169 7 24.14 180 9.5 22.43 166 6.5 25.54 185 10 20.24 171 7 24.43 Analysis Firstly the data will be given a Pearson correlation coefficient test to see whether there are correlations between the data obtained. In this test, if the number obtained from the test is 1, it means that there is a perfect correlation between the two data. However, if the number obtained from the test is 0 it means that there is no correlation at all.

    • Word count: 832
  5. Investigating an enzyme-controlled reaction: catalase and hydrogen peroxide concentration

    There was no reaction in the distilled water but as the concentration of hydrogen peroxide increased, 5% to 25%, the more amount of oxygen was produced, 2.00mL to 5mL in the first trial. Also, the conical flask became warm as the reaction occurred. It indicated that heat was released and it meant that there was an exothermic reaction. Data Processing Table 2: The average amount of oxygen produced in the different concentration of hydrogen peroxide Concentration of hydrogen peroxide% (mol L-1)

    • Word count: 3789
  6. Yeast fermentation

    is available for yeast reproduction and increase the amount of sugar the yeast can react with, we expect the yeast will use the sugar for energy and reproduction. Explanation Yeast can extract more energy from sugar when oxygen is present in their environment. In the absence of oxygen, yeast switch to a process called fermentation. With fermentation, yeast can still get energy from sugar, but less energy is derived from each sugar molecule. In this laboratory I will add the same amounts of yeast and water to different amounts of sugar in water bottles and cap them with a testing tube to see how much carbon dioxide gas is produced.

    • Word count: 1869
  7. Plant Science Lab Report

    Not only cells are affected in this process, the photosynthesis system can also get affected also. As because when the salt dehydrates the cells no water is available for photosynthesis. The salt also penetrates its way to the chloroplast. The salt would then accidentally be used in the process of photosynthesis. Therefore ending the process of photosynthesis. Controlled Variable: - Same type of plant - Same location - Same amount of water in plants - Same casing for the plant - Same amount of soil Independent Variable: - Concentration of NaCl (0%, 5%, 15%, 10%) Dependent Variable: - Growth of plant Materials: 1- NaCl [salt] 2- 4 plants of the same kind 3- 50 ml beaker

    • Word count: 1066
  8. Bipedalism vs. Quadrapedalism

    A bipedal organism has an easier ability to see ahead and find the quickest way to his home. If being on two legs makes traveling with food easier than the bipedal organisms will have the fastest time because they are using fewer muscles and body parts to get around. Ho: There is no difference between the amount of the time it takes to carry food between bipedal and quadrapedal organisms. Ha: There is a significant difference in the amount of time it takes to carry food between the two organisms. Variables Independent: Walking up the steps on four legs or two legs and carrying a book or no book.

    • Word count: 1284
  9. affect of light intensity on rate of photosynthesis

    Dissolve 1g of NaHCO3 (use balance to weight NaHCO3) in water to give CO2 supply 3) Mark each beaker with letters A, B, C, D, and E 4) Measure pH level of the 5 beakers before the experiment 5) Place same size Inelodea (7 cm long) in to beaker A 6) Place the beaker 20 cm apart from the lamp (using ruler to measure this distance) 7) Measure the pH of the solution each 2, 4, 6 and 8 minutes 8) The experiment is repeated for beakers B, C, D with distance 40 cm, 60 cm and 80 cm away from the lamp 9)

    • Word count: 1045
  10. Identification of Organic Compounds

    The copper ions immediately react with oxygen to form copper oxide which forms a reddish brown precipitate. The redder the solution looks, the more copper oxide there is, and therefore the more sugar is in the solution. Problem Can the effect of the reaction of the Benedict's reagent to test for the presence of simple sugars (monosaccharides and reducing sugars) with the known solutions be used to determine the unknown solution? Hypothesis Based on the background information, if the Benedict's reagent causes the solution to turn green, yellow or brick-red, then we can conclude that there is a presence of

    • Word count: 3984
  11. effect of microwave radiation on lentil seeds lab report

    "The experimental results showed that it is possible to heat the plants with microwaves without visible damage, and no increase in susceptibility to gray mold" (International Society for Horticultural Science) "microwave pretreatment can improve the inner energy of seeds, lead to an enhancement of cotyledon enzymes, and speed up the metabolism of the cell" (Journal of integrative plant biology) My hypothesis is that if the seeds were micro waved for 10 seconds, they will sprout before all the other variables and the control.

    • Word count: 1870
  12. IB Genetic Unit Notes

    Halving of the chromosome number of gametes is essential because at fertilisation the number is doubled. Therefore each of the daughter cells will have half the number of chromosomes of each type is present in the nuclei which is called haploid (n) [mitosis produces two daughter cells that have the full number of chromosomes which is called diploid (2n).] Meiosis undergoes two divisions of the nucleus - meiosis I and meiosis II. 4.2.2: Define homologous chromosomes Homologous chromosomes resemble each other in structure.

    • Word count: 4474
  13. Factors Affecting the Rate of Photosynthesis Lab

    room's lights will stay on, and I will include this in the measurement of light using a lux meter), time allowed for plant to photosynthesize between trials (I will let the plant sit for 1 minute under the intensity of the light I am testing and then commence counting bubbles every 30 seconds for 3 consecutive trials) Hypothesis: I expect that, at low light intensities, the rate of photosynthesis will be slower than the rate of photosynthesis at higher light intensities because the chlorophyll in the elodea is absorbing less light, so fewer bubbles will be produced, compared to higher intensities.

    • Word count: 2151
  14. Invertebrate Biodiversity Lab

    Most invertebrates in the area will be attracted to the smell of the olive oil, and when they eventually fall in they will not be able to escape due to the slippery environment resulting from the olive oil. The oil will also suffocate them. If more invertebrates and a greater biodiversity are found in Area 2 then the conclusion can be based on the absence of human influences and also the greater availability of food and shelter, which has not been destroyed by human activities.

    • Word count: 3386
  15. Radioactive Lab

    The techniques are varied and complex. The methods involve a number of assumptions with varying degrees of certainty. The most common dating methods are radiocarbon (often called carbon-14), used for dating materials of biological origin. Half-life is the amount of time it takes for half of the atoms in a sample to decay. How accurate is radiometric dating? I don't believe it is that accurate and it is unreliable. The interpretation of these ratios, in terms of age, depends upon theories. Theories are just assumptions that are not necessarily true or valid. The nuclear decay process seems to be random yet predictable.

    • Word count: 613
  16. Plant Science

    Nitrogen promotes rapid growth, increases leaf size and quality, and promotes fruit and seed development. Phosphate ions are a component of cell membranes, certain proteins, all nucleic acids and nucleotides, it is involved in energy transfer such as ATP and ADP. It activates coenzymes for amino acid production used in protein synthesis; and it is involved in many other metabolic processes required for normal growth, such as photosynthesis, glycolysis, respiration, and fatty acid synthesis. Potassium ions helps to determine an anion-cation balance in cells and activates enzymes to metabolize carbohydrates for the making of amino acids and proteins.

    • Word count: 805
  17. Hill Reaction Lab

    This is the photosynthesis factor which behaviour is investigated. Dependant variable: the rate of photosynthesis, id est the speed of the bubble which is affected by the excess by the waste product, oxygen. This is the best way to have a good estimation of the rate of photosynthesis, which we are trying to establish a relationship with light intensity. Controlled variable: Local and ambient temperature (of the room), the experiment was done in the same room with the school air conditioning system keeping the room at a constant temperature.

    • Word count: 2214
  18. Photosynthesis Lab

    Method Material Used: * Chloroplast solution pre-extracted from spinach * Diluted DCPIP solution * Pipette * Small beaker * Vernier Colorimeter with 8 plastic cuvettes for the DCPIP-Chloroplast-Buffer solution * Phosphate reaction buffer * Lamp with a 40W light bulb * 1 meter ruler * A timer Steps: 1. The colorimeter wavelength was set to 635 nm. 2. A cuvette was filled with the 2 ml of buffer and 1ml of chloroplast solution it was then placed into the colorimeter to calibrate it (Averaging 100% absorbance).

    • Word count: 1717
  19. Brain Cancer and Cell Phones

    The research takes place in part of a large international study, which is known as "Interphone", and it is coordinated by the World Health Organization's Cancer Research Institute. Scientists are using lab rats to observe if there are any connections between cell phones and brain tumor. They believe that the risk of getting brain tumor is due to the microwave radiation in mobile phones, where the magnetic field is attracted from the telephone posts. Dr Henry Lai and Dr. N.P Singh believed that, "the radiation changed brain cell membranes in the rats - and the effects are so severe that it could affect humans, too."

    • Word count: 1520
  20. To investigate the effect of varying phases of mitosis on the duration of each of the phases by measuring the percentage number of cells

    In other words, prophase takes the longest time while anaphase takes the shortest time in mitosis of two roots. Independent variable Different phases of mitosis, from prophase to telophase Dependent variable The average percentage number of cells in each phase of each root 3. Apparatus and Materials Apparatus 1 Microscope Material 1 slide of the root tip of Allium 1 slide of the root tip of Vicia faba 4. Procedure See the worksheet 5. Results Table 1 showing the number of cells in each phase of mitosis in Allium Different phases in mitosis Number of cells Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 Sample 7 Prophase 58 30 29 33 35 37 24 Metaphase

    • Word count: 1309
  21. To investigate the amount of protein present in different types of milk by measuring the mass of protein in each types of milk.

    stirring the solution All types of milk are stirred for 90s Rinse the acid Run distilled water through the precipitate to rinse off the acid 3. Apparatus and Materials Apparatus 2 50ml measuring cylinder 2 100ml beaker 1 syringe 1 funnel 1 stopwatch 1 petri dish 1 electron balance weighing up to 0.1g 1 busen 1 glass rod Materials 20ml dilute HCl 40ml full cream milk 40ml skimmed milk 40ml goat's milk 40ml soya milk 2g MgSO4 4 filter paper 4 cheese cloth Distill water 4.

    • Word count: 1582
  22. To investigate how the different concentrations of hydrogen peroxide influences the activity of catalase.

    Hypothesis The rate of breakdown of hydroxide peroxide by catalase would decrease as the concentration of hydrogen peroxide decreases. This is because the amount of hydrogen peroxide decreases, thus the activity of catalase will also decrease. Independent variable Concentration of hydrogen peroxide solution, 6%, 3%, 1.5%, 0.75%, 0.375% Dependent variable The rate of breakdown of hydrogen peroxide by catalase is measured in term of time Controlled variable Variable How it is controlled Volume of hydrogen peroxide used 5cm3 of each H2O2 solution is used The amount of chicken liver used A piece of chicken liver is used for each concentration The length of the fluid in the manometer rises The length of the fluid in the manometer to rise

    • Word count: 1024
  23. IB Genetic Lab

    The dependent variable is inheritable gene, which is where the phenotype derives from. The controlled variables are that only females were surveyed, the same measuring tape, and the method for measuring arm span that was used throughout the experiment, and that when measuring height, the individual had to remove her shoes to ensure that no extra height was added. Materials * Measuring tape (750cm � 0.1cm) * Paper with observation tables * Pen Procedure 1. Ask the female to stretch her arms so that the arms are parallel to the ground and perpendicular to their body.

    • Word count: 1824
  24. Affect of temperature on enzyme peroxidase

    thus increasing the rate of reaction, or the enzyme activity.1 Also, the collisions between substrate and active site happen more frequently at higher temperatures due to faster molecular motion, and this also results in increase in enzyme activity.2 However if the temperature of the enzyme peroxidase increases beyond the optimum temperature of the enzymes, then the rate of reaction or the enzyme activity will dramatically decrease, which will be indicated by a longer time in seconds taken for the red water to reach the marked distance.

    • Word count: 2995
  25. Investigating Macromolecules and their Properties

    Since proteins are made up of amino acids, and amino acids react with Biuret reagent, one of our solutions which would be a protein will turn either pink or violet depending on the complexity and concentration of the protein. (MadSci Network). Benedict's solution is a chemical reagent used to identify monosaccharides (simplest form of carbohydrates, also known as simple sugars). It is prepared from sodium carbonate, sodium citrate and copper (II) sulfate. The solution changes its color according to the concentration of monosaccharides present.

    • Word count: 2090

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