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International Baccalaureate: Biology

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  1. Biology practical

    Catalase also uses Hydrogen Peroxide to oxidise toxins including Phenols, Formic Acid, Formaldehyde and Alcohols. In this practical, the reactions occuring in the substances where catalase( in a form of liver) is added, are observed and recorded. The testing requires 8 test tubes ,which of 1 is filled with 4 ml of distilled water and from 2-8 is filled with 4 ml of fresh H202. Every test tube recives an additive,which is placed there after the H202/distilled water; Tube 1: cube of liver Tube 2: small amount of manganese

    • Word count: 445
  2. Types of organic compounds & where they are

    Results (a) Data Collection & Presentation "The type of organic compounds in some foods" Starch Test (Iodine Solution): Type of Food Color Known - Potato Black Unknown 1 - Tofu No Change; White Unknown 2 - Egg Solution No Change; Yellow Unknown 3 - Milk No Change; White Monosaccharide Test (Benedict's Solution): Type of Food Color Known - Glucose Solution Dark Orange Unknown 1 - Tofu Grey/Light Blue Unknown 2 - Egg Solution Grey/Light Purple Unknown 3 - Milk Dark Yellow/Brown Lipid Test (Sudan III solution): Type of Food Observations/Color Known - Vegetable Oil Thin, transparent, orange upper layer Thick,

    • Word count: 827
  3. Duchenne Muscular Dystrophy

    Early symptoms will appear at varying degrees, including, the ability to walk, sit straight, breathe normally, and move the arms and hands freely. All these weaknesses will increase with age, and may also lead to other health problems. Figure 1 below shows a sufferer of DMD: "DMD sufferer" Since DMD is a global disease, infecting children all over the world, all of them will of course need a wheelchair at some point, so the wheelchair will affect the lives of these children all over the world, to make them feel able.

    • Word count: 1852
  4. Isotonic Point of Potatoes

    Using a measuring cylinder (+/- 0.05 cm3) the same volume of water will be measured out for each solution. The duration of the exposure of the potato strips to the solution. The duration of the experiment will be the same for all the samples as all the potato strips will be removed from the specified concentration solutions at the same time, thus keeping the time constant Ambient Factors All the samples are kept in an air conditioned room where the room temperature is kept constant at 27.3 Co (+/- 0.1 Co) Surface area of the potatoes (cm2) (for each solution's samples.

    • Word count: 2446
  5. Penicillin - its discovery, properties and uses.

    For example, against cell wall biosynthesis or as inhibitors of protein biosynthesis. The evaluation of new antibacterial molecules typically follows a hierarchical procedure. First, a new compound is tested against a panel of bacterial strains, many of them pathogens arising from clinical isolates, and many of those possessing resistance to prior generations of antibiotics. If a new antibiotic candidate show that sufficient potency against marker strains, then the molecule may be evaluated in animals inoculated to have high levels of infections with specific strains of bacteria in particular tissues, such as bacterial infections of blood and bacteremia, to see if the candidate molecule is protective and curative.

    • Word count: 4653
  6. Exercise and Heart Rate Design lab

    treadmill for a minute * Lifting weights of 15kgs in each hand for a minute -DEPENDENT VARIABLE- Different heart rates -CONTROLLED VARIABLE- * The time spent (i.e.: one minute on each exercise) * The atmosphere and temperature should be the same for all exercises * The subject's pulse rate should return to normal before another exercise APPARATUS: To conduct the exercises we require, 1. A flight of stairs (long enough for the subject to run up it for a minute)

    • Word count: 623
  7. Mitosis Lab report

    The centrioles start to produce mitotic spindles, which are extending across the cell. Metaphase: The nuclear membrane is fully disappeared, and the mitotic spindles are rapidly extending across the cell. The spindles are then attached to the kinetochore of each chromosome, and the spindles align the chromosomes in the middle of the cell. They are aligned in the middle so that when separated in anaphase, the nucleus from the two daughter cells will get a copy from each chromosome. Anaphase: The chromosomes separate from the kinetochore, and so one chromatin from the chromosome goes to one side, and the other chromatin gets pulled to the other side.

    • Word count: 1627
  8. Browning Enzyme

    In order for me to calculate an appropriate mean and to calculate the standard deviation (this will improve my accuracy) Null Hypothesis: The rate of browning is not increased by an increase in the temperature in which it is place. Hypothesis: When fruits or vegetables are peeled or cut, enzymes contained in the plant cells are released. The presence of oxygen from the air, the enzyme polyphenolase causes the conversion of phenolic compounds to melanins (brown pigment). Polyphenoloxidases, in plants, are usually found in the chloroplasts, although they can be released from here ripening.

    • Word count: 3503
  9. Pros and Cons of GMO crops

    A gene, which is the physical unit of heredity, contains a molecule that decides the function and structure of all organisms, called the DNA. The DNA molecule is made up of four different nucleotide basis that are linked up together in pairs within a long string, forming a code. Whether it is a blade of grass or a human being or a pond scum or an insect, their DNA consists of the same nitrogenous bases (figure 1), but arranged in a different sequence.

    • Word count: 3780
  10. Enzyme Lab

    The amount of water displaced is a result of the enzyme-catalyzed reaction. By using different concentrations of the substrate (H2O2), we are able to find out just how much a change in the concentration of substrate affects the rate of the enzyme-catalyzed reaction. Therefore, by finding out what concentration produces what results, we can apply this to instances where we may want to alter the rate of enzyme-catalyzed reactions to aid us in a way that is in our convenience. Hypothesis The higher the concentration of substrate is, the faster (more water displaced)

    • Word count: 2553
  11. Osmosis Lab

    Hypothesis The higher the concentration of salt solution in the beaker (environment outside of the semi permeable tubing), the faster the rate of osmosis will be out of the "cell". The lower the concentration of salt in the solution, the slower the rate of osmosis will be. This is due to the fact that the salt (solute) decreases the concentration of the water outside of the cell, which contains a 100% water (solvent). Water will go out of the higher concentration inside the cell and out to the lower concentration where the salt is.

    • Word count: 2432
  12. Molecular Genetics: differentiating between various molecular databases

    For this experiment, the amino acid sequences for the protein Insulin were used, mainly because these are short and easier to compare. * The type of family to which the four species belong to is also a control variable. For this experiment, the four chosen species belong to the rodent family. This will help us investigate the differences among the species of the same family. * The characteristics of the species that were compared during the experiment were a control variable.

    • Word count: 2435
  13. Environmental Factors affecting plant growth

    * The amount of light received by the plants was a control variable. Every time the plants were placed in the same place which was next to the window. So, daily they received the same amount of light. * The tubes were also a control variable. The tubes in which the plants were placed were all of the same size. They all had a volume of 22cm3. * The water retaining gel powder was also a control variable as well. In each tube about 2.2g of it was used. * The weighing scale used to measure the plant gel was also a control variable.

    • Word count: 4338
  14. Pill Bug Lab

    They are also most active at night and prefer higher levels of soil, so the amount of soil they are living in could affect their activity. I collected my bugs from my family's garden in my backyard and from potting soil that I found around San Bruno park. I created the habitat I would keep them by, first, putting a moist paper two at the bottom of a plastic container. Then I put soil and a little bit of vegetation on top of that, and finally, I put the Pill bugs in their new habitat.

    • Word count: 2087
  15. Protists - Study Guide

    It gave rise to the organelles that we see today in eukaryotic cells. 3 structural features of the mitochondrion: - has its own DNA with a slightly different genetic code and its own ribosomes - is enclosed in a double membrane - replicated through binary fission, like bacteria 4. The nucleus became surrounded by a double membrane because when it became reliant to the host cell, in order to stop macromolecules from diffusing freely between the nucleoplasm and the cytoplasm, a double membrane must be formed to act as a barrier.

    • Word count: 1602
  16. Enzyme-Substrate Specificity

    In this case, hydrogen peroxide is the substrate. The rate at which this substrate of the enzyme is broken down will be calculated by the measuring the temperature by placing a thermometer near the core of the reaction. The highest temperature at each of the different substrate concentrations will be recorded and used. This particular situation will aid us into discovering a possible trend between the rate of enzymatic activity and substrate concentration. We predict that as we increase the concentration of substrates added to the enzyme, the rate of enzymatic activity will increase.

    • Word count: 3095
  17. DNA; Past, Present, and Future

    and prokaryotes do so in the cytoplasm. Chromatin proteins in the chromosomes compress and organize DNA, thus maneuvering the interactions between DNA and other proteins. DNA was discovered for the first time in 1869, by Swiss physician Friedrich Miescher. He discovered a microscopic substance in the cellular nuclei of the pus of discarded surgical bandages, which he named "nuclein". A short while later, in 1919, Phoebus Levene discovered the general structure of DNA; the sugar and phosphate base. Although he thought that DNA consisted of a string of nucleotides through the phosphate groups, he was incorrect in suggesting that the chain was short and the bases repetitive in a fixed manner.

    • Word count: 2564
  18. Factors affecting the rate of transpiration

    As the cohesion tension theory explains it, water molecules are polar, meaning that they stick to one another. If one molecule moves, it pulls adjacent molecules. The water is able to evaporate out of the leaf through diffusion as the leaf has a high water potential and the air has a low water potential, making it possible for water molecules to pass down the concentration gradient from the spongy and palisade mesophyll cells into the leave's internal air spaces before diffusing out into the air. Teachers aim Investigate rate of water loss of a plant under different environmental conditions.

    • Word count: 1646
  19. Biology Lab Design Glucose concentration

    Variables Variables Units Range Independent Fruit used - - Dependent Percentage of absorbance % 1-100 Controlled variables are maintained at a constant Controlled Variables Units Possible effect(s) on results Method of Control Volume of benedict's solution added & Volume of the fruit juices ml This is done to ensure the full reaction between the benedict's solution and the sample of fruit juice. 4.5 ml of benedict's solution and fruit juice will be added to the boiling tube using a syringe.

    • Word count: 1407
  20. Phantom Limb Syndrome

    (Abstract from "Missing Limbs, Still Atingle, Are Clues to Changes In the Brain") Phantom limb syndrome describes the perception of sensation of an already amputated limb. The victims that have this condition feel that the amputated arms or legs are still attached, and oftentimes they have the misleading imaginations where they can feel and even complete jobs with their missing hands or feet; for example, one could try to gesture while he is talking even though he doesn't even have a full arm. However, the most common symptom and the majority of this disturbing sensation is pain; it's called the phantom pain.

    • Word count: 1511
  21. Designer Babies

    Geneticists are able to differentiate between both chromosomes by means of a simple light-sensitive dye, which, of course, stains the X chromosomes a shade darker, due to the presence of denser DNA. (Designer Babies - TIME.) After having chosen the desired gender, the fused egg and sperm may now undergo a Pre-implantation Genetic Diagnosis (PGD), during which the growing embryo is screened for genetic diseases and characteristics before being inserted into the carrying mother. A choice is now present, the parents may either implant the embryo and await the surprising characteristics, or they may actually allow the geneticists to sort the embryo's genetics, in order to perceive the wished for traits.

    • Word count: 1110
  22. Protein Purification Lab

    Solid proteins/food samples tested Steamed tofu Boiled boneless skinless chicken breast Boiled egg white Cheddar cheese Mixed nuts Hypothesis The protein digestion rate of different types of solid proteins will be different. The type of solid protein with the highest protein to fat concentration ratio will have the highest digestion rate as it takes more energy to break down lipids as one gram lipids gives off 9 calories compared to 4 calories from protein. Lipid is hydrophobic macromolecule which means it will water in the stomach thus decrease the digestion rate.

    • Word count: 3014
  23. Botany Lab Report

    The soil where plants live is dry due to water shortage. Plants have smaller leaves and they grow closely to the ground. Their leaves have wax for protection from dehydration and white hair on some plants also help to reduce the evaporation of water on leaves' surface and reflect sunlight. Leafless plants carry out photosynthesis at their green stem (cactus). Plants like cactus and Ponytail Palm has a cone shaped thick stem to store water. Those characteristics help plants in extreme environment to survive.

    • Word count: 1379

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