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International Baccalaureate: Biology

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  1. What is the time-course of enzyme to catalyze the breakdown of a protein, into its smaller units, amino acids?

    I will take the amount of green light absorbed by the solution; this will tell me the colour of purple that is present in the solution. The higher the protein concentration, the darker the purple or the solution and thus the more green light was absorbed. Figure 2: Colorimeter 2 To measure the amount of protein present in the samples, I will compare the absorbance of the samples given to the calibration results. For example, if the samples give an absorbance (AU)

    • Word count: 1093
  2. All animals and plants are attacked by parasites and pathogens; evolution is the results of an arm race between the parasite and the host

    Evolution occurs faster in pathogens than they do in humans (mammals). This is due to factors such as: the changing life span and generations of pathogens occur faster than those of humans. There are much higher populations of pathogens this allows more evolutionary changes to occur. Pathogens are smaller organisms; this means that there are fewer functions, less complexity and fewer physical aspects that need evolving, making mutation much easier. Pathogens are also simpler organisms and so a fewer changes in them will have much more of an effect than it would in a more complex organism like a mammal.

    • Word count: 949
  3. Beetroot Plasma Investigation. The main objective of this investigation is to focus on the effect of ethanol (C2H5OH) on the plasma membrane of a beetroot.

    It will be measured in percentage transmission by the calorimeter connected to the data logger therefore it will be quite precise. Independent Variable - * Concentration of Ethanol: The variable we will be changing is the concentration of ethanol solution used, which will be 0, 20, 40, 60, 80, and 100% ethanol, with an uncertainty of +/- 0.1%. Controlled Variables - * Volume of ethanol used - The volume of ethanol will be the same for every slice of beetroot in order to have a just experiment.

    • Word count: 1592
  4. Osmosis Investigation - effect of different strength of glucose solution on potato and apple strips.

    Volume of the glucose solution which is fixed to 20 ml. The volumes are kept constant at 20 cm3 by measuring them using a measuring cylinder at each trial. Materials: 50cm3 of 1.0 mol dm-3 glucose solution, distilled water, potato tuber, apple and filter paper. Apparatus: Boiling tube, cork borer, 15 cm ruler, razor blade, tile, 25.0 cm3 measuring cylinder, forceps, covered Petri dish, stop-watch, marking pen, labelling paper and a 50 ml beaker, 10 cm3 pipette. Data collection and processing: Quantitative data : Table 1.1: Table shows the recorded data for the initial length of the apple strips, cm and the final length of the potato strips, cm.

    • Word count: 2285
  5. A Local Ecosystem, Patterns in Nature,Life on Earth,The Australian Biota

    Glucose is what provides energy to the consumers which is vital for growth and reproduction. In addition, photosynthesis produces oxygen, which is essential for the process of respiration. This is important in ecosystems so that energy can be delivered to cells that can be used in growth, development and reproduction. * Identify uses of energy by organisms Energy from respiration powers all the processes of life. Some energy is released as heat, which can help keep the animal warm and maintain optimal temperatures for the chemical reactions that occur in cells.

    • Word count: 11141
  6. investigating the water potential of potato cells

    Water potential quantifies the tendency of water to move from one area to another due to osmosis, gravity, mechanical pressure, or matrix effects such as surface tension. Water potential has proved especially useful in understanding water movement within plants, animals, and soil. Water potential is typically expressed in potential energy per unit volume and very often is represented by the Greek letter ?. Hypothesis: in this experiment, 6 different concentrations of sucrose solution will be used to find the water potential of potato cells.

    • Word count: 1858
  7. Investitigation of Veins and arteries. Research topic: the elasticity of cows vein and aorta hung with different masses.

    In this experiment, I will examine the elasticity of these blood vessels. Materials and apparatus: * Cow's vein * Cow's aorta * 1 Stand and clamp * 1 Paper clips * 1 Ruler (+/-0.5mm) * 10 Weights of 100 grams each Method: 1. Cut out a ring of 3mm from the aorta and another from vena cava 2.

    • Word count: 506
  8. An experiment to investigate the action of saliva on starch:

    It is produced by all green plants as an energy store. It is the most important carbohydrate in the human diet and is for example contained in potatoes, wheat, maize (corn) and rice. Human saliva is rich in amylase, and the pancreas also secretes the enzyme. Iodine solution is used to test for starch; a dark blue colour indicates the presence of starch. Hypothesis: The longer starch and saliva are mixed, the more starch is broken down and the iodine will become brighter. As the solution is mixed with Benedict's solution and heated in a water bath, it will change it's colour, indicating that the starch in the solution has been broken down to reducing sugars by the amylase in the saliva.

    • Word count: 1140
  9. Hair Lab Report - investigate the force needed to break down a hair and to investigate if characteristics found in different hairs make a change in the strength these have.

    Choose a hair, and tight it to the force meter apparatus. You should already have the first weight (100g) hanging from this apparatus. 4. Be aware that the hair is correctly tightened up, if it does, start adding more weight. First the cylinder weighing 100 g and afterwards the 10g weights. 5. When the hair breaks, record the amount of weight that it was put. 6. Repeat steps 3, 4 and 5 with all of the other hairs. Results: Name Color and type Treatment Length (cm)

    • Word count: 648
  10. Examine how the concentration of hydrogen peroxide affects the rate of reaction of the enzyme catalase.

    * Controlled variable: Temperature Materials: * Yeast Catalase * Hydrogen Peroxide * Test tubes * Beakers * Test tube rack * Stop watch * Pipette * Distilled Water * Pipette filler * Gas syringe * Stand Method: 1. Add 100% of hydrogen peroxide into the beaker. Connect this, to the gas syringe and measure the volume of oxygen produced every 30 seconds. 2. Every 30 seconds shake the beaker twice and then clean it. 3. Add 80% of hydrogen peroxide and 20% of distilled water into the beaker.

    • Word count: 775
  11. Experiment Colours of Light (Wavelength) absorbed by green plant

    This will ensure that the contents of the extracted pigments will be subjected to different colours. 440nm, 470nm, 490nm, 520nm, 550nm, 580nm 590nm and 680 nm Dependent Variable The amount of absorption of light by the extracted pigments. The value of light absorbed is measured from a calorimeter. The calorimeter will register the result of the absorption of light corresponded to the wavelengths. - Controlled Variable How to control Type of organisms used The experiment is carried out by using the same organism in the experiment which is plant organisms.

    • Word count: 3998
  12. How the Heart Works

    The middle layer is called the myocardium which consists of all the contracting muscles (cardiac muscles). The inner layer is called the endocardium, and the smooth inner lining is in contact with the actual blood of the heart. Endocardium is also present in the soft inner lining of blood vessels. In humans, and all other vertebrates (backbone), the heart is composed of cardiac muscle (cardiac comes from kardia, the Greek word for "heart", and literally means "related to the heart"), a special type of muscle fiber not found anywhere else in the body, and connective tissue.

    • Word count: 2950
  13. How are interactions between neural cells established and maintained?

    The exact form of the adult cell is controlled by the location of progenitors during differentiation, as well as by diffusible factors acting from a more distant site, usually the final location to which the differentiated cells will migrate. Signalling molecules influence the differentiation of neural stem cells. For instance valproic acid (VPA) actively suppresses glial differentiation, instead encouraging the development of adult neurons, via upregulation of the neurogenic basic helix-loop-helix transcription factor (Hsieh, Gage 2004). The mesenchymal stem cell (MSC)

    • Word count: 1440
  14. Stomach Cancer

    There are two main forms of stomach cancer, diffuse and intestinal, with the diffuse type affecting more of the non typical individuals, eg females and younger (see risk factors below). Diffuse and intestinal stomach cancers differ both in location and causative factors. 90% of stomach cancers are adenocarcinomas derived form the glandular tissue. Risk Factors As stomach cancer is multifactorial there are no causative factors as such, rather risk factors and predisposing factors, the most significant of which is Helicobacter pylori infection.

    • Word count: 939
  15. Independent Research Project Vital Lung Capacity

    Individuals with asthma have trouble breathing due to blockage of the airways. A spirometer was used in order to measure and determine the vital capacity of each of the two participant groups: individuals with asthma and individuals without asthma. Respectively, the mean vital capacity values of both these groups were calculated and compared and contrasted with each other. Based on medicinal investigation, it is hypothesized that there will be a minor difference between the average lung capacity of individuals with asthma and individuals without asthma. Confounding variables in this experiment such as the age of the subjects, the equipment used and the environmental factors in the testing situation are closely inspected to avoid any invalid results.

    • Word count: 2355
  16. Enzyme IA Biology

    when cooled. Independent Variable: Temperature of enzyme liver -Increased the liver temperature by 22�C from room temperature of the catalase solution to correlate a high temperature at 44�C -Decreasing the liver temperature by 22�C from room temperature of the catalase solution to correlate a low temperature 0�C -Increase is by 22�C because in order to reach 0�C it must be decreased by 22�C from room temperature -Begin with room temperature Dependent Variable: Amount of Oxygen produced from the liver, Hydrogen Peroxide reaction (ml)

    • Word count: 2188
  17. IB biology Respiration IA

    Since increasing time increment of exercise should require more energy, it is expected that the rate of CO2 production will increase; therefore the time it takes for BTB to change color will decrease. Research Question: What is the effect on increasing time of exercise on the rate of CO2 production? Variables: The independent variable is time spent exercising The different levels of the independent variable are 30 seconds, 60 seconds and 90 seconds The dependent variable is the time taken to change BTB color The controlled variables include type of exercise, volume of BTB, straw length, color gauged, same timer per test subject, same test subject per trial.

    • Word count: 2178
  18. ProblemWhat kind of roles the factors of pH levels and temperature have on various reaction rates. What roles inhibitors and activations play on enzymatic reactions.

    Investigating the uncatalyzed rate of decomposition, an individual was picked from the group to come in the following day and test the effect of leaving the H2O2 in room temperature for 24 hours. By comparing the results between the two, we were better able to understand the effects enzymes play in reactions. Emphasis: Data Analysis and Collection Objectives: Before doing this lab you should understand: * the general functions and activities of enzymes; * the relationship between the structure and function of enzymes; * the concept of initial reaction rates of enzymes; * how the concept of free energy relates

    • Word count: 2663
  19. Digestion Lab. The specific purpose of this lab (activity 4) was to investigate fat digestion by pancreatic lipase and the action of bile, and to recognize whether fat digestion is ongoing or completed (2).

    Methods: The experiment was carried out by placing 6 test tubes, labeled 1 to 6, on the test tube holders in the incubation unit. Each test tube holds different solutions: test tube 1 contains lipase, vegetable oil, bile salts, and pH 7.0 buffer; test tube 2 contains lipase, vegetable oil, deionized water, and pH 7.0 buffer; test tube 3 contains lipase, deionized water, bile salts, and pH 9.0 buffer; test tube 4 contains deionized water, vegetable oil, bile salts, and pH 7.0 buffer; test tube 5 contains lipase, vegetable oil, bile salts, and pH 2.0 buffer; test tube 6 contains lipase, vegetable oil, bile salts, and pH 9.0 buffer.

    • Word count: 929
  20. This experiment was conducted to determine food preference of planaria. Planaria are freshwater creatures. They live in lakes, streams, and other freshwater bodies.

    Gather materials. 2. Label the choice chambers A, B, C, D, and E 3. Fill all of the choice chambers with 100mL of water 4. Place on type of food in each of the choice chambers, completely in one of the chambers (excluding the last choice chamber, which will have no food) 5. Add five planaria to each chamber that does not have food in it 6. Allow the planaria to move as they please for fifteen minutes 7.

    • Word count: 593
  21. Yeast Population

    The different amounts of sugar that will be used in this experiment will be, 0g, 1g, 2g, 3g, 4g and 5g. This is the independent variable because this is the variable that will be altered, while the others will be controlled. Dependent Variables The dependent variable in this experiment was the yeast population. This will be recorded through the observations through the microscope. This is the dependent variable because it depends on the independent variable, as sugar affects the yeast population.

    • Word count: 1624
  22. The aim of the experiment: To investigate the effect of different glucose concentrations on the rate of fermentation.

    This causes an increase in yeast activity and the overall rate of fermentation. Level of sugar and salt: It is well known that yeast fermentation is retarded in the presence of high concentrations of sugar and salt. This inhibitory effect is related to the high osmotic pressure gradient created outside of the yeast cells due to high concentrations of sugar and/or salt .But in presence of appropriate sugar concentrations rate of fermentation will increase , but it will eventually stop."(1) 1 http://www.dakotayeast.com/help-fermentation.html Ethanol fermentation "Ethanol fermentation (performed by yeast and some types of bacteria)

    • Word count: 1587
  23. Seed germination experiment. Aim: To investigate the following factors affecting seed germination (warmth, water, light, air)

    * Boiling tube rack: to hold the boiling tube while we are preparing the experiment V) Method: We put five boiling tube in a boiling tube rack. In the five boiling tube we put a cotton wall at the bottom with 10 seeds on it. Then we take one of the boiling that we put aside. This boiling tube will be the case with no water.

    • Word count: 564
  24. Ecology Design IA

    Many epiphragms are calcareous, or contain high calcium-carbonate content. This aids in the strength of the bond between the organism and the surface it wishes to attach itself to. "Gastropods can also create a calcerous epiphragm, prior to annual hibernation." (Wikipedia, 2010) An epiphragm is not to be confused with an operculum, which is a physical attachment to the muscular foot which allows the organism to retain its moisture. While any epiphragm does essentially allow the organism to stick to the surface indefinitely, the organism can be removed from the surface with a certain amount of force.

    • Word count: 1735

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