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International Baccalaureate: Biology

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  1. Water potential of potato cells experiment.

    It was also very rigid and hard. 0.1M solution:- The potato chip increased in mass. It was relatively hard and rigid but not as much so as the chip immersed in distilled water. 0.2M solution:- The potato chip decreased slightly in mass. It felt the same as before 0.3M solution:- The potato chip decreased in mass. It was a bit softer than before submersion. 0.6 M solution:- The potato chip decreased mass. It was very soft and flexible. Results: Sucrose solution concentration (M)

    • Word count: 755
  2. Fermentation lab report. Bubbles were observed when three sugars were added to the yeast solution (glucose, lactose and maltose)

    As for the measuring device, we calculate the least reading and divide it by 2 and so in this case the least reading on the cylinder is 2, therefore the uncertainty is ±1 Graph (1) This graph presents the change in level of water in the cylinder ±1 cm3 every 300 seconds, using the four types of sugar. Data Processing To measure the rate of reaction due to the fermentation of yeast using different types of sugars, the volume of the carbon dioxide should be calculated first.

    • Word count: 902
  3. Many opinions about how to tackle the research and development of viruses and vaccines has to do with two entities: the federal government and the private sector.

    After the Spanish Flu began declining in early 1920 (Anderson, 2006), the study of viruses picked up slowly. 1939 was the first time that the characteristics of a virus, specifically the growth of bacteriophage in a cell and the burst which releases them, was accurately described (Helton, 2009). This research was one of many monumental steps toward our current understanding of viruses (Anderson, 2006). Now that the importance of understanding and predicting viruses is accepted, the issue we face in the 21st century is how to reach the most number of people in the least amount of time with the most effective solution. This question, however, requires insight into the entities that predict and react to viruses today.

    • Word count: 1080
  4. Bionics and Prosthetics - the future possibilities.

    Part One - The Neurobiology of the Human Body The human body is a brilliant machine on its own. With its own system of fuel flow in the form of blood and veins, and an engine-like heart, the body is truly a machine. Yet what makes this even more prominent is the interconnecting nexus of electrical impulses in our body, complete with main circuitry being the brain and spinal cord. This nexus is able to send unlimited messages to all its parts, able to grow and shrink with age, and most importantly able to control all movements and thoughts.

    • Word count: 1094
  5. Soil testing lab

    Percent of Water = Loss in mass after drying / mass of original soil * 100 Masses of the soil and pans (+/- 0.01g) Original Soil After Oven Empty Pan Soil Water Mass of original soil Percent Water in the Soil % Soil A 160.35 138.20 13.30 22.15 147.05 15 Soil B 142.40 124.78 13.30 17.62 129.10 14 Sample Calculation: 1. Soil Water = 160.35 ? 138.2 = 22.15 1. Mass of original soil = 160.35 ? 13.30 = 147.05 1.

    • Word count: 699
  6. bio lab - The Effect of Temperature (C) on the Rate of Diffusion in seconds

    One drop of food colouring will be used for all trials. Concentration of the food colouring The concentration of the food colouring should be kept the same. If there is an increase in the concentration then there will be more molecules in the same amount of volume and that will result in a decrease in the rate of diffusion. More molecules will have to move from region of high concentration to a region of low concentration and thus take more time. To keep this variable controlled, food colouring of the same type and brand will be used.

    • Word count: 1576
  7. Genetic engineering has been a controversial topic

    The gene to be inserted into the genetically modified organism must be chosen and isolated for identification. After the gene is isolated, the gene is inserted into a bacterial plasmid. At the construction stage, the gene can be modified for better effectiveness, and to control the location and level of gene expression. Then, gene targeting uses homologous recombination to target desired changes to a specific endogenous gene. Next, in the transformation stage, the genes to be inserted are cloned into a binary vector, which when constructed, will naturally insert the genetic material into the plant cells. In the selection stage ( since not all the organism?s cells will be transformed)

    • Word count: 1496
  8. Does the color of light affect the growth of an Alaskan pea plant?

    The embryo within a seed will eventually die while it is dormant if it doesn?t begin germination by a certain time. Depending on the seed, the length of viability can be a few weeks, to hundreds of years (Germination). Germination begins when dormant seeds are under conditions that are necessary for growth and survival, such as light, water and warmth (Kennell). Germination is the process in which growth in a plant seed are activated from a resting stage and begin to grow (Kennell).

    • Word count: 1488
  9. Enzyme Experiment Design

    My aim is to find the maximum rate of reaction at which the enzyme is working at its greatest efficiency when increase in concentration will result in no increase in enzyme activity. Research Question What is the effect of substrate (hydrogen peroxide) concentration on the rate of reaction between hydrogen peroxide and catalase? Hypothesis I believe that as the substrate concentration (hydrogen peroxide concentration) increases that rate of reaction will also increases. However, as it reaches the maximum substrate concentration, when all active site are full and working at maximum efficiency.

    • Word count: 815
  10. Biology Research Paper-Gigantism is a condition characterized by abnormal or excessive growth and height significantly above average

    The term ?gigantism? does not apply to those who are simply ?tall? or ?above average? whose heights appear to be the healthy result of normal genetics and nutrition. If excess growth hormone occurs after normal bone growth has stopped in adulthood, the condition is known as acromegaly, which is a long-term condition in which there is too much growth hormone and the body tissues get larger over time. Symptoms include: congestive heart failure, glucose intolerance, and diabetes if left untreated.

    • Word count: 1449
  11. What is the effect of pH levels on the net production, given by the change in dissolved oxygen, in Chlorella pyrenoidosa?

    In this experiment, the effects of pH on the net production, from change in dissolved oxygen, were studied. Question: What is the effect of pH levels on the net production, given by the change in dissolved oxygen, in Chlorella pyrenoidosa? Hypothesis: If the test bottles (150 mL containers) are filled with about 20 mL of cultured Chlorella pyrenoidosa sample and 130 mL of pH solutions from pH 6, 7, 8, 9, and 10, and the test bottles are exposed to conditions suitable for survival of Chlorella pyrenoidosa , then the test bottles that contain the optimum pH, that is the

    • Word count: 5357
  12. Biology lab What effect does age have on the breathing rate and heart rate during exercise?

    The candidate had to count their breathing rate per minute. Every exhale and inhale was considered one. The candidate then took to the stairs where the subject ran at his own pace. Each candidate ran for 1 minute (60 seconds) under a stopwatch or phone. Once the participant had run 1 minute, the pulse and breathing rate it taken quickly for one minute. Again the candidate measures their own breathing rate as the heart rate is taken for him by the wrist or the neck (depending on where we found a good beat)

    • Word count: 934
  13. Design Lab on Enzyme Activity

    As the reaction continues, however, the rate at which oxygen is released gradually slows down. The explanation for this is that as more and more substrate is converted to product there are fewer and fewer substrate molecules to bind with enzymes. As fewer substrate molecules are left the reaction becomes slower and slower .The reaction can be stopped through denaturation of the enzyme most likely through injection of the acid HâSOâ or an increase in temperature. Hypothesis 1: The rate at which the enzyme catalase breaks down hydrogen peroxide varies with time. Investigation plan: In the reaction between hydrogen peroxide and catalase the rate of the decomposition of hydrogen peroxide can be measured by measuring the rate at which oxygen gas is given off.

    • Word count: 621
  14. Enzymes (REVISION)

    Substrate The substrate of an enzyme are the reactants that are activated by the enzyme. Cofactors An additional non-protein molecule that is needed by some enzymes to help the reaction. Tightly bound cofactors are called prosthetic groups. Cofactors that are bound and released easily are called coenzymes. Many vitamins are coenzymes. Inhibitors Inhibitors are chemicals that reduce the rate of enzymic reactions. The are usually specific and they work at low concentrations. They block the enzyme but they do not usually destroy it. Many drugs and poisons are inhibitors of enzymes in the nervous system FACTORS THAT AFFECT ENZYME ACTIVITY Substrate concentration Non-enzymic reactions The increase in velocity is proportional to the substrate concentration .....

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  15. Overview of Cells & Energy (Revision)

    lenses to provide magnifications. Cannot resolve details better than about 0.2 mm(micrometers) Advantages of light microscopes: Enables user to see larger structures within eukaryotes and distinguish individual prokyrotes. They are user-friendly: small, portable, easily-prepared slides, relatively cheap to buy and maintain. Both living and dead material may be viewed. Material is rarely distorted by preperation. Thicker materials may be viewed Allows experimenter to view image directly. Allows for specimen to be observed in natural state. Slides are simple to prepare Faster Color Can observe movement. Electron microscopes: Uses an electron beam instead of a light beam, and electromagnets instead of lenses.

    • Word count: 1875
  16. IB Biology Digestive System

    - Enzymes are globular proteins that increase the rate of a reaction by lowering the activation energy. - The Digestive enzymes are released into the gut from glands to break down larger molecules. - By lowering the activation energy with enzymes, the reaction does not require high temperatures and this is beneficial to the process because high temperatures are damaging to the cells and proteins. 4. State the source, substrate, products and optimum pH of one amylase, one protease and one lipase. Enzyme Salivary Amylase Pepsin Pancreatic Lipase Source Salivary glands Wall of Stomach Pancreas Substrate Starch Proteins Triglycerides (fat or oils)

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  17. When one species influences another species evolutionary development it is known as Coevolution

    The communal relationship between the insect and the flower for survival is coevolution. Not only does the relationship that Darwin observed help the species survive, but it also causes them to evolve in order to achieve a more seamless relationship with each other, and thus a better probability of survival. The two species will evolve through natural selection to better fit each other?s niche. If a flower has a very deep nectary, insects that have long proboscises will be able to reach the nectar of the flower and survive, while insects with short proboscises will die.

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  18. There are many examples of natural selection. One of the most famous is that of Darwins finches.

    A warbler finch has a small pointed beak and it catches flying insects on the wing. The cactus finch has a long thin beak so that it can probe between the spines to take nectar from the cactus flowers and eat the seeds. The woodpecker finch has a very hard beak that it uses to hammer wood, and it is able to use a cactus spine to probe the bark for insect larvae. Another commonly referenced example of natural selection was observed in the 19th century in Great Britain, and was caused due to polymorphism of colouration in moths.

    • Word count: 846
  19. Investigation of osmosis in potato strips by measuring the length of the strips after a incubation in various sucrose concentrations

    If there is a difference between two different solution concentration. The one with highest solute concentration is hypertonic in relation to the one with lowest solute concentration. The solution with the lowest solute concentration solute is hypotonic to the one with high solute concentration (hypo means under or less than). These words can only be used to compare solutions. Considering that two solutions are separated by a selectively permeable membrane. The solution that is hypertonic to the other has higher solute concentration and therefore the water concentration is lowered compared to a hypotonic solution where the solute concentration is lower and the water concentration is higher.

    • Word count: 2642
  20. How will changing the percentage of glucose concentration affect the light transmission percentage from the release of betacyanin caused by the permeability of cell membranes of beetroot cells?

    Hypothesis I predict that as the concentration of glucose increases, the solution will become darker in colour thus the light transmission percentage will decrease. This is due to the water potential of the surrounding glucose solution being lower than the water potential inside the beetroot cell causing water to exit the cell through osmosis. As the cell becomes flaccid for a long period of time, it will start to wilt. This causes the cell membrane to tear away from the cell wall and the permeability to increase so the red pigment betacyanin would be realeased.

    • Word count: 2072
  21. Nucleic Acids and Proteins Exam Prep. Notes

    7.1.4 Distinguish between unique or single-copy genes and highly repetitive sequences in nuclear DNA. Nuclear DNA The nucleus of a human cell contains nearly 2m of DNA, but genes make up only a proportion of this. The DNA in a eukaryotic cell can be divided up into two types: Unique or single-copy genes, which make up 55-95% of the total Highly repetitive sequences, or satellite DNA, which account for 5-45%. The repetitive sequences are typically between 5 and 300 base pairs long and may be duplicated as many as 100 000 times in a genome.

    • Word count: 1291
  22. Experiment to test touch sensing in boys and girls

    - The time it took each gender to try to guess the letter they were feeling. Control Variable: - Location - Age (between 5-6) - Time of day Materials - Box with two compartments and two holes big enough for hands to be able to go through. - Bag - Two alphabets with Styrofoam letters - Two stopwatches Procedure: Insert a Styrofoam alphabet into each box compartment. Separate the students by gender and tell them that it is a game. Pick a girl and a boy to do the experiment and set them side by side with their hands by their sides and facing the box.

    • Word count: 979
  23. Comparing the effect of different antimicrobials on the growth of E.coli

    It is effective against Hemophilus influenzae, Streptococcus pneumoniae, Mycoplasma pneumoniae, Chlamydia psittaci, Chlamydia trachomatis, Neisseria gonorrhoeae, and many others. Tetracycline prevents growth of bacteria by preventing the bacteria to manufacture proteins that they need to survive.?[7] Research question Does a higher concentration of an antimicrobial have a stronger inhibiting effect on Escherichia coli? Which of the antimicrobials has the strongest inhibiting effect on the growth of the bacterial culture of Escherichia coli?

    • Word count: 2736
  24. An experiment to determine the effect of caffeine on heart rate

    The same method is used while finding the heart rate. The time gap between drinking the energy drink and taking the heart beat after drinking This will remain as 1 hour for each experiment and a stopwatch will be used to ensure that the time gap remains 1 hour in each case. The measuring cylinder used to measure the volume of the energy drink The same 250ml measuring cylinder will be used while measuring the volume of the energy drink needed.

    • Word count: 1002
  25. Modifying a simple hydrolysis of sucrose experiment to measure Michaelis Menten constant for the dextrase content of yeast

    Using a clean pipette in each case, transfer the following into each fermentation tube. (1㤠of distilled water, 0.5% sucrose, 1% sucrose, 5% sucrose, 10% sucrose, 20% sucrose) For each tube, add 1㤠of yeast and top up with distilled water. (Mix the yeast by swirling the flask before putting the yeast to each tube) Push each fluid-filled fermentation tube to end of each test tube with pencil. Tap the outer tube firmly to release any bubbles trapped at the mouth of the inner tube.

    • Word count: 1645

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