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International Baccalaureate: Biology

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  1. Comparing successive phases of mitosis using the compound light microscope.

    In telophase the nuclear envelope forms around the new formed chromosomes which than unfold to chromatin. The cell wall forms and 2 cells separate from each other. Research question: How does the chromatin change throughout mitosis? Hypothesis: In prophase chromosomes will be seen inside the nucleus. In metaphase aligned chromosomes in the middle of the cell will be seen. Separate chromatids being pulled apart will be seen in anaphase. In early telophase two nuclei's inside one cell will be seen. Explanation of hypothesis: In prophase the chromatin in nucleus condenses to form chromosomes. In metaphase the chromosomes are line up in the middle of the cell.

    • Word count: 555
  2. Biological Membrane Lab

    It is predicted that the higher the concentration, the more the light absorbed and thus the more damage is caused to the plasma membrane. Hence, 40% causes the most damage to the membrane followed by 30%, 20%, 10% and finally 0%. Variables: * Independent Variable(s): Type of Alcohol (Methanol, Ethanol, 1-Propanol) and Alcohol Concentrations (0%, 10%, 20%, 30%, and 40%) * Dependent Variable(s): The amount of red pigment released ( Absorbance) * Controlled Variable(s): room temperature, test tubes, beetroot, colorimeter, lab- pro, and power supply.

    • Word count: 1270
  3. In Vitro

    The most common fertility treatment used is an injectable Gonadotropin (Gn) such as Follicle Stimulating Hormone (FSH). Close monitoring, including frequent Estradiol level checks and ultrasounds to monitor follicular growth, must follow the fertility treatment. After adequate follicular maturation, Human Chorionic Gonadotropin (HCG) is injected, which acts as an analogue of Luteinizing hormone (LH). LH is a hormone which matures the egg and weakens the wall of the follicle in the ovary, triggering Ovulation (approximately 36 hours after injection). However the egg is retrieved directly from the ovary using an ultrasound-guided needle.

    • Word count: 675
  4. Extended Essay: An Investigation Into the Differences In Life Expectancy For Males and Females In two Different Time Periods, 1900-1920 and 1980-2000.

    A number of vaccines were developed between 1900 and 2000. For example the first vaccine for Diphtheria was developed in 1923, which was closely followed by the discovery of a vaccine for pertussis (more commonly known as whooping cough) in 1926. These discoveries were later followed by the development of vaccines for Tuberculosis and Tetanus in 1927, influenza in 1945, [1] Poliomyelitis in 1955, [2] Pneumonia in 1977, and meningitis in 1978. [1] Through the use of intense immunisation programmes instigated by the World Health organisation, Smallpox, which killed an estimated 300 million people worldwide in the 20th century alone, was declared to have been eradicated worldwide in by the WHO in 1980.

    • Word count: 4418
  5. Free essay

    Factors that affect the population size of an immobile population

    Photosynthesis is the production of food compounds from carbon dioxide and water by green plants using energy from sunlight, absorbed by chlorophyll i.e. Photosynthesis is how plants feed. lightlightlil 6CO2 + 6H2O C6H12O6 + 6O2 Plants use the light to break down the water molecule into oxygen hydrogen ions and electons, were the hydrogen ions combine with the carbon dioxide to produce organic molecules, while the oxygen is released, and the electrons are used to produce ATP and NADPH+H to power up the production of the organic product TP from GP through the calvin cycle occurring in the stroma of the chloroplast of the plant cell.

    • Word count: 893
  6. LAB-What infuences blood pressure

    If someone exceeds 25, than there is higher probability of obesity and cardiovascular problems. The value below 19, on the other hand means that someone has underweight. These intervals are presented on the graph 1, and there is also small table nr1. below. Graph 1. The presentation of Body Mass Index intervals showing some tendencies. Table 1. BMI values and their interpretation. BMI General characteristic The risk of a disease Below 18,5 Underweight Low 18,5 - 24,9 Norm Average 25 - 29,9 Excess weight High 30 - 34,9 Excess weight I degree Higher 35 - 39,9 Excess weight II degree Very high 40 and more Excess weight III degree The highest The other way to determine obesity is to measure the waist size.

    • Word count: 5564
  7. Predator Prey Simulation Lab Report

    ==> PROCEDURE: 1. Place 3 "prey" on the table. 2. Toss 1 predator onto the table (evenly dispersed) and attempt to make the card touch as many "prey" as possible. In order to survive, the predator must capture at least 3 preys. It will be impossible for the predator to survive at this point. 3. Remove any "prey" captured and record the data for the 1st generation. 4. The "prey" population doubles each generation. Count how many hares are left on the table, double that number and add prey cards to the table. Record the number in the data table under the 2nd generation "number of hares".

    • Word count: 801
  8. extended essay

    From this statement, one can come to the conclusion that, "laboratory reproduction is radically human compared to conception by ordinary heterosexual intercourse. It is willed, chosen, purposed and controlled, and surely they are among the traits that distinguish Homo sapiens from others in the animal genus" 4. Numerous questions are asked on the subject matter of human cloning, such as: "Will cloning really help improve the problems in our society by creating smarter clones? What determines an "improved human"? Why is cloning still practiced, if it is shown to destroy certain important human values, such as: parenthood, marriage, and the family?

    • Word count: 3373
  9. Modeling an Ecosystem's Carrying Capacity

    In recent years, scientist have successfully attempted to manipulate the carrying capacity of certain ecosystems by introducing foreign species to the areas; such cases include the introduction of wolves to Yellowstone National Park, and the introduction of both wolves and moose to Isle Royale. The theories that derived from the original studies of Howard Odum, and the recent findings of ecologist involved in such cases as Yellowstone and Isle Royale have lead to an understanding of the carrying capacity of an ecosystem.

    • Word count: 1932
  10. Genetic Variation

    The following part deals with chromosomal mechanisms. There are four different results that occur when there is chromosomal breakage. A deletion occurs when a chromosomal fragment lacking a centromere is lost. Sometimes a deleted fragment may become attached as an extra segment to a sister chromatid, producing a duplication. A chromosomal fragment may also reattch to the original chromosome but in the reverse orientation, producing an inversion. A fourth possible result of chromosomal breakage is for the fragment to join a nonhomologous chromosome, a rearrangement called a translocation. Crossing over greatly contributes to genetic variation in the fact that it is the reciprocal exchange of genetic material.

    • Word count: 974
  11. the ozone and the greenhouse effects

    The stratosphere consists of a relatively high concentrations of ozone. Ozone depletion is caused by the building up of man-made chemicals in the atmosphere. One of the main chemicals is generally known as CFC. CFC's do not break down they float in the atmosphere, they rise for about eight years until they reach the ozone layer where they are broken apart by large amounts of ultraviolet radiation. CFC's are able to "live" for about 20 to 100 years. Ozone depletion gets worse when the stratosphere is very cold.

    • Word count: 775
  12. Biology - Observing the Process of Guttation

    The differences in temperature in the exposed and enclosed containers may cause more or less water to be exuded through guttation. Guttation occurs when the atmospheric conditions cause a reduction in transpiration and an increase in humidity. Hypothesis: If plants usually perform the process of guttation under conditions of high humidity and low transpiration, then the leaves of the green bean sprouts grown inside the enclosed containers should exude more water than the ones grown in the exposed containers because there is greater humidity and less transpiration inside the enclosed container, causing the leaves of the green bean sprouts to

    • Word count: 3160
  13. Tuberculosis (TB) is a serious, re-emerging bacterial illness that usually affects the lungs. People with TB infection can take medicine to keep them from getting TB disease.

    There are two forms of TB: TB infection and TB disease (or active TB). Most people with TB have TB infection. What is the infectious agent that causes tuberculosis? Tuberculosis is caused by Mycobacterium tuberculosis, a bacterium. Tuberculosis is found worldwide. How do people get tuberculosis? Tuberculosis is spread from person to person through the air. People with TB disease of the lung spray the bacteria into the air when they cough, sneeze, talk, or laugh. People nearby can breathe in the bacteria and become infected.

    • Word count: 595
  14. Atomic structure for Biochemistry revision poster

    * There are 3 types: 1)Ionic bond: metal + non- metal (ex: NaCl, BeF2) and 2)Covalent bond: non-metal + non-metal (ex: O2, H2, N2) and 3)and 3)Polar Covalent bond: between 2 non-metals/metals, electrons are not shared equally.(ex: HCl) 1)London Forces ?Weakest, between atoms and molecules, Formed temporary by uneven number of electrons 2)Dipole-Dipole Forces ?between polar molecules ? positive end of one molecule attracts negative end of another molecule --Stronger than London forces 3)Hydrogen Bonds ?Strongest force ? between N, O or F of one molecule AND H of another.

    • Word count: 622
  15. Should CRISPR-Cas9 be used to revive extinct species?

    Although this method speeds the outcomes but is often misguided as it results in creating species that are not genetically diverse and incapable of adapting whenever there was any change in its environment. https://lh6.googleusercontent.com/FfAyVb31AH75JDOsznD5vlkCz27BO1jaFManXNRVpEHuwaWy4k--J-hX7mo9WaqTCggt8zvsubo6BZsIQec_Y_h9FmQKfjO6k4qa-aqeuxoj1uDJLpvzLK3RXrdP4TMh2pywZMZaklzup5j0Iw However, Scientists took other innovative approaches to fix the damage and revive extinct animals through gene-editing techniques. With the genetic engineering technology CRISPR-Cas9, researchers have discovered a way to reconstruct and edit DNA and restore the earth's natural restoration and function. CRISPR or (Clustered Regularly Interspaced Short Palindromic Repeats)

    • Word count: 1295
  16. Effect of Incandescent, Fluorescent and LED lights at 900 lumens on the concentration of vitamin C content in oranges and their effectiveness on metabolic efficiency

    Incandescent generate light by use of filaments and when power is applied, the filament glows generating heat and therefore light. Due to incandescent bulbs hot filament, they produce a continuous spectrum as all wavelengths of lights are present (Fielder 1). On the other hand, led produces lights through a cold process as it is stimulated by electron movement, hence creating photons, therefore, visible light and its wavelength is the only thing emitted by led bulbs (Lighting Division 1). Fluorescent lighting uses electricity to excite mercury gas and in the process emits ultraviolet light (Nave).

    • Word count: 6452
  17. Environmental Mangement - Upland Burning in Ireland and the Effects of the Heritage Bill 2016.

    The Heritage Bill 2016 will also Acts amend and extend the Wildlife Act 1976 and outline the powers issued to the authorized bodies under the Act. Provisions will also be made in the Bill to amend the Canals Act 1986 (Department of Arts, Heritage and the Gaeltacht, 2016). The Bill comes as a manifestation of the Irish Government?s poor record in listening to the cohorts of people who value our natural heritage. This is evident in the lack of scientific rationale to support these changes (birdwatchireland, 2017).

    • Word count: 3429
  18. River Thame Investigation How does the distribution of mayfly larvae depend upon the rate of flow of the river

    Variables: Independent ? speed of the stream Dependent ? number of mayfly larvae Controlled ? number of times data collected at each site, how the samples are collected ? kick sample and speed probe, transect across the stream at three places, data collected on the same day ? similar weather conditions. Method Materials: Speed probe from field centre, macro invertebrate net, Wellington boots, meter ruler, string, temperature probe The stream was sampled at the place it enters the field centre, where there is a meander and as it leaves the field centre ? just after a weir.

    • Word count: 1271
  19. Causes of Alzheimers Disease

    Plagues are clusters of protein fragments called beta-amyloid that are built up between the nerve cells. Tangles are made up of twisted strands of protein called tau. http://thebrain.mcgill.ca/flash/d/d_08/d_08_m/d_08_m_alz/d_08_m_alz_1a.jpg Beta-amyloid is a fragment of a protein found in the neuron?s cell membrane called amyloid precursor protein (APP). APP is a transmembrane protein, which means the APP molecule passes through the cell membrane of neuron. In order for beta-amyloid to be released from the APP molecule, two enzymes must be involved which are beta-secretase and gamma-secretase. http://thebrain.mcgill.ca/flash/d/d_08/d_08_m/d_08_m_alz/d_08_m_alz_1b.jpg First, beta-secretase cut the peptide chain of APP outside the cell membrane at a certain length.

    • Word count: 715
  20. What are the uses of enzymes to diagnose a disease?

    To diagnose whether a patient has a disease, the doctor will take some blood in order to look for abnormal amounts of specific enzymes in the blood and then measure the plasma levels of the enzyme. Below is an image illustrating this. (Figure 1 taken from ?Clinical Enzymology?) Higher levels intracellular enzymes indicate cell damage as enzymes are meant to be inside the cells. If you find them in the plasma that means the cell walls have been damaged. Although if someone has low levels, it could also simply be because of genetics or due to the fact that it is natural change with age.

    • Word count: 1120
  21. Comparing the Sexy Sons Hypothesis and the Pathogen Avoidance Models Effects on Sexual Selection

    The pathogen avoidance model states that females select for males with secondary sex traits in order to distinguish between the diseased and the healthy males in order to stay safe from pathogens. Both theories are widely used to explain many evolutionary trends, but are they mutually exclusive? It is possible that both theories are correct in certain scenarios. However, one must look into the mechanisms of both in order to find out. Overview of Sexy Sons Hypothesis The sexy son hypothesis which was popularized by Ronald Fisher is currently stated as a possible explanation for the great diversity of ornamental traits in animals.

    • Word count: 4422
  22. Designing an Osmotic Potential Experiment with Potatoes

    I will also be setting up an experiment to show the mass change of the vegetables in each of the solution, and trying to find the osmotic potential of the vegetable. Hypothesis. According to particle theory, water molecules are in constant motion. As they move, they hit the membrane and create a pressure against the membrane called the water potential. Solutions with a low water potential have a high solute (osmotic) potential. Therefore, solutions with a high water potential have a low solute (osmotic)

    • Word count: 1923
  23. Genetically Modified Organisms Essay

    With the world?s population expected to reach 9 billion by 2050 demand for critical resources such as proteins continue to exceed supplies. Scientists are close to developing and engineering a genetically modified salmon. Genetically Modified organisms (GM or genetically modified organisms) are organisms or plants with altered DNA, giving them greater resistance to pesticides and herbicides and improved nutritional content. GM foods were originally intended to reduce the diseases and pesticides on crops, leading to a larger output of crops for a cheaper price.

    • Word count: 2042
  24. Investigating the Effects of Salt on Seed Germination

    The dependent variable (the variable being measured): The dependent variable is going to be the percentage of seeds that germinate over one week in each petri dish/NaCl solution. We will count the total number of seeds in each petri dish and after one week; count the number of seeds that germinated so that we can calculate a percentage. The control variables (the variables kept the same): The other variables, which we need to keep constant, are: * The same number of seeds used for each petri dish (10 seeds).

    • Word count: 2728

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