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International Baccalaureate: Biology

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  1. Aim To investigate the effect of strenuous physical activities such as badminton and bodybuilding on the heart rate of subject compared to stationary position

    During the initial portion of the cardiac cycle, an electrical signal is generated in pacemaker cells that is distributed through the heart through an electrical conduction system. In response to that particular electrical stimulation, the myocardium of first the atria and then the ventricles undergoes contraction (systole), followed by sequential relaxation (diastole) of the two sets of cambers a fraction of a second later. This cycle of compressing on the blood in the ventricles during diastole induces pressure changes in the ventricles that cause one-way valves in the heart to close audibly at different intervals of the cardiac cycle.

    • Word count: 1355
  2. Investigating the effects of plant density on growth rate

    Once the seed has germinated, the roots will start to grow towards the soil and the sprout will grow upwards. As the first tiny leaves appear, photosynthesis is started. In the next stage of growth the plants start to compete for water and nutrients in the soil and also for sunlight and carbon dioxide above. Seeds that are planted too close to one another are known to grow taller initially to compete for sunlight (Dictionary.com 2012, Etiolation). However this growth will not last long because as they grow bigger, the plants will have to compete for other resources in the soil like space for roots, water and nutrients (Wikipedia 2012, Factors Affecting Growth).

    • Word count: 2132
  3. Measuring the effects of wind and light on the transpiration rate in a leaf

    This process is known as transpiration (Raven et al., 2002). Transpiration is a vitally important process in plants, and to study it further we designed and conducted an experiment to measure the rate of transpiration in the tomato plant, Solenum lycopersicum. In order to study the effects of varying weather conditions on the process, we studied how the transpiration rate would be affected by light, wind, and both light and wind (Vodopich et al., 2002). We hypothesized that these variables would increase the rate of transpiration.

    • Word count: 1277
  4. Stem Cell Research Essay

    The process of this bone marrow stem cell transplant begins with chemotherapy in order to kill the abnormal cancer cells as well as the normal cells present in the bone marrow. The new hematopoietic stem cells given to the patient via blood transfusion begin to produce new, healthy blood cells in a matter of a few days. Stem cells for transplants such as these are obtained from either adult tissue such as bone marrow; or from multicellular embryos such as embryos created during in vitro fertilization, embryos created in somatic cell nuclear transfer, germ cells or organs of an aborted fetus or from the blood cells of the umbilical cord after birth.

    • Word count: 1377
  5. Experimental Question: What effect does substrate concentration have on the rate of enzyme activity?

    Dependent Variable: Rate of the enzyme activity in the reaction (measured in secs) Controlled Variables: Type of Enzyme (constant catalase obtained from beef liver) Room Temperature (constant 25OC) Materials: 1. (1) 100mL Graduated Cylinder 2. (1) Test Tube with a rubber stopper 3. (1) 200mL Beaker 4. 3% Hydrogen Peroxide Solution (H2O2) 5. Distilled Water 6. Test Tube Rack 7. Stopwatch 8. Catalase obtained from beef liver (Enzyme Solution) 9. Forceps (1 pair) 10. Petri Dish 11. 6mm Disks cut from the filter paper Experimental Procedure: 1.

    • Word count: 1513
  6. Differences between prokaryotic and eukaryotic cells

    A Eukaryotic is composed out of 5 different ribosomes while a Prokaryotic is only composed of 3 different ribosomes. 1. There is more space within a Eukaryotic cell than there is within a Prokaryotic cell. 1. A cytoplasm in a Eukaryotic cell is filled with large and complex organelles, many of which are enclosed in their own membranes. A Prokaryotic cell contains no membrane bound organelles. 1. Eukaryotic cells are larger than Prokaryotic cells by 10 times. 1. Eukaryotic cells either have a plasma membrane or a cell along with the plasma membrane while prokaryotic cells have a plasma membrane in addition to a bacterial cell wall.

    • Word count: 632
  7. Outline Scientific Advances in the Fight Against AIDS

    HIV can be transmitted through direct contact of mucous membrane or bloodstream with someone containing the virus. The transmission can happen through many different ways, such as: unprotected sex, childbirth, blood transfusions, breast milk, injection drug needles and any type of blood direct contact. Even though, we have a lot information about what AIDS and HIV are and what they do to humans, scientists still have not figured out why the HIV virus is so powerful that can kill almost all human immune cells. It is scary how the amount of people contracting HIV is getting bigger everyday and that almost 90% of our population is infected by this virus, and from 42 to 59% of the people infected by it those do not have any type of treatments to go against this.

    • Word count: 1016
  8. The Effect of pH on the activity of enzyme Catalase

    When the enzyme shape is altered, it becomes denatured. Variables: Table 1: Variables Selected for this Experiment Variables Independent Variable Different pH concentration Dependent Variable Time to raise the manometer fluid to rise by 5 cm Control Variables Temperature, same amount of potatoes, same amount of pH solution, same amount of H2O2 Materials and Methods: 1. Fresh potato 2. Boiling tube -1 3. Single bore rubber bung 4. Cork borer 5. White tile 6. knife 7. Small beaker 8.

    • Word count: 904
  9. How does cooking affect the amount of vitamin C in lemon juice?

    The volume of glacial acetic acid used. 4 cm3 of glacial acetic acid used for dilution in all types of lemon juice. 4. Type of fruit used to prepare juice sample. Juices are extracted from lemon fruits for every trial. This is because different fruits contain different concentration of vitamin C, thus using variety of fruits will greatly affect the reliability of the data. Apparatus & Materials / Procedures Refer to the handouts. DATA COLLECTION AND PROCESSING 1. Data Collection 1.

    • Word count: 2693
  10. Female Fertility Problems Essay

    According to FertilityCommunity.com (Ovulation Disorders), ?Ovulation disorders, infrequent or absent ovulation (anovulation), frequently result in infrequent periods, (oligomenorrhea).? The results of ovulation disorders are fewer oppurtunities for conception to occur in a woman, causes the egg not to break though the follicle (caused dues to hormone imbalances, because LH levels might be decreased), creates difficulty discovering the periods in which the woman is fertile, and cause a preterm or late release of the egg making the egg off sync with the other factors that are imperative for fertilization and implantation to occur.

    • Word count: 1406
  11. The Story of the Discovery of DNA

    Meanwhile during this time, the only research regarding DNA was able to prove that the genetic material was DNA, but the structure of the molecule remained unknown. However, there was little known information concerning the structure of DNA termed Chargaff?s Rules which resulted from Chargaff?s study of DNA from various species. He discovered a ratio of nitrogenous bases. He recorded that there were equal proportions of adenines to thymines as well as guanines to cytosines. The significance of this took a while to get noticed.

    • Word count: 1266
  12. The Importance of Sleep

    Sleeping helps your brain recover knowledge you may have forgotten during the course of the day. It also helps us remember the sequence of events; it has been found that long term memories are formed while we sleep, this being accomplished by the brain replaying memories while we sleep. Sleep not only strengthens the content of memory, but also reestablishes the order. Consequences of Sleep Deprivation âImpaired Memory and Thought Process âFatigue âIncreased Pain âDepression âPoor memory âDecreased Immune Response Caffeine and other energy stimulants can temporarily overcome the effects of sever sleep deprivation, but only for a limited amount of time.

    • Word count: 647
  13. Effect of Detergent on Membrane Permeability

    Question: What is the effect of detergent on organic membrane? Aim: To be able to use the colorimeter to measure the amount of absorbance and transmittance of the betalaine pigment in the beetroot and find out the effect of different concentration of detergent on the cell. Hypothesis: Null Hypothesis: 1. If the percent increment of detergent increases when applied on the beetroot, the light absorption rate from the colorimeter will remain the same because there is no relationship between the concentration of detergent to the absorption rate Alternative Hypothesis: 1.

    • Word count: 2436
  14. The Effect of Alcohol on Biological Membranes

    Discard the ethanol. 5. Prepare five ethanol solutions. To do so, repeat Step 3, substituting ethanol for methanol. Place each solution in the second row of wells. See Figure 1. 6. Prepare five 1-propanol solutions. To do so, clean your pipette and repeat Step 3, substituting 1-propanol for methanol. Place each solution in the third row of wells. See Figure 1. 7. Now, obtain a piece of beet from your instructor. Cut 15 squares, each 0.5 cm X 0.5 cm X 0.5 cm in size. They should easily fit into a microwell without being wedged in. While cutting the beet, be sure: ? There are no ragged edges.

    • Word count: 1405
  15. Determine the effect of average height of males and females and whether their mean heights are more or less the same

    The gender of the child also factors. For most peoples in the world, adult males on average tend to be taller than adult females. For males mother?s height is added to father, plus 5 inches, the sum is then divided by two. For females, mother?s is added to father?s, again calculated in inches, but five inches are subtracted from the total, divided by two. This is a predictor of a child's height in adulthood, save a few inches. Family members are likely to be of similar stature.

    • Word count: 626
  16. Deteremining The Effect Of Substances On Membrane Of A Cabbage Cell

    Substance added to cabbage discs pH (±) Color Distilled water 6 slightly violet NaOH (1mol/dm³) 14 yellow HCl (1mol/dm³) 1 red Ethanol 5/6 purple only right around the cabbage discs near the bottom; clear on top of liquid Cabbage discs boiled in distilled water 5/6 purple, but less intense color than the red or yellow Table 2: Raw data collected by Bolayır’s group on color change of cabbage in different substances with average pH obtained. Discussion As we conducted our experiment using heated distilled water, ethanol, HCl, NaOH, and distilled water we had the opportunity of observing how different substances with different properties and even under different conditions affected the membrane of a cell.

    • Word count: 1164
  17. (IB) Ecology Observation Report. The tree that Ive chosen to observe from March to June is located between the playground and the Main Hall

    From research, I have found a web article illustrating on method of classifying pines[1], which belong to Class Pinus. I am not yet certain whether or not ?X? belongs to Class Pinus, but this article may serve as blueprints for formulating my own dichotomous key. Initial Observations My initial observations on Mar. 27th provided me with basic knowledge about Tree ?X.? ?X? has needle-like leaves whose color ranges from olive yellow to dark green. Yellowish leaves tend to be more located to the bottom of the tree whereas the top has mostly dark green leaves.

    • Word count: 1666
  18. Do the different dilutions of yeast cell suspension affect the number of yeast cells per cm3 that counted using haemocytometer under the microscope?

    This is because when more distilled water used, the smaller the ratio of yeast suspension to distilled water become. It means that the less yeast cell suspension will occupy the dilutions per cm3 as the yeast cell suspension get more diluted because the yeast cells had been widely distributed. Variables Independent variable : Different dilutions of yeast cell suspension which are one-to-hundred dilution (1/100), one-to-one thousand dilution (1/1000), one-to-ten thousand dilution (1/10,000), one-to-hundred thousand dilution (1/100,000) and one-to-one million dilution (1/1,000,000).

    • Word count: 1627
  19. What is the color of pigment that can be found in green plants at different wavelength using a colorimeter?

    Qualitative data: Mustard: 1. The green mustard was put into the boiling water and then it become softer than it was before. 2. The mustard was grind using a mortar until it become it form of paste. 3. When it was in that form, it released an odor that can be smell. 4. The colorless acetone was added and grind together. 5. Then, the solution produce was transfer into centrifuge tube and after the process using the centrifuge was done, the layer between supernatant and the precipitate which both are green in color.

    • Word count: 1339
  20. THE EFFECT OF TEMPERATURE ON THE MOVEMENT OF PIGMENT THROUGH THE CELL MEMBRANES

    ________________ Mean= sum of all data values/the number of data values. ________________ this is the formula of standard deviation. It measures the Spread of the data values from the mean. ________________ CONCLUSION Figure 1 showing cell membrane structure From the graph it is evident that as the temperature increases, the % transmission of light through the solution(distilled water and anthocyanin) decreases.Therefore it can be deducted that temperature is one of the factors that affect the diffusion of anthocyanin because the amount of anthocyanin diffused in the distilled water was dependent on the temperature level the sample was in, for example at 45°c,the % light transmission was 99.4%(0.6% absorption)

    • Word count: 1013
  21. Bio practical - The influence of pH on the activity of catalase

    catalase on hydrogen peroxide as the number of oxygen bubbles produced per minute were different for each buffer solution with a different pH level whilst every variable was held constant. The optimum pH of catalase is pH7 as it produced the highest average of 99 oxygen bubbles per minute. As the pH moved away from pH7, less oxygen bubbles were produced, for example pH3 had the lowest average of 11 oxygen bubbles produced per minute as it was the farthest from pH7.The bell shaped best curved fit on graph1 supports this explanation.

    • Word count: 947
  22. Experiment-Effect of Temperature on the Action of Amylase Enzyme

    Thus, the rate of reaction of amylase correlates to the absolute value of the rate of change in absorbance of the solution. A rapid decrease in the absorbance of the blue-black color equates to a high rate of reaction of amylase, whereas a slow decrease in absorbance signifies a low rate of reaction. In this experiment, an external variable of temperature will be manipulated into the amylase enzyme to determine the effect of temperature on the rate of reaction of amylase enzyme.

    • Word count: 2152
  23. Biology Investigation - Comparing the populations of two plant species in same area.

    Research question: Which species is more populated in the IB MCKK compound? Aim: To compare the population sizes of Mimosa Pudica and Chrysopogon aciculatus (Retz) Trin in IB MCKK compound. Hypothesis: Mimosa pudica will occupy larger areal coverage in IB MCKK compound than Chrysopogon Aciculatus (Retz) Trin. IB MCKK compound is a windy area and populated with many small butterflies. Using insects and wind as medium of pollination, this is such an advantage for the growth of Mimosa Pudica populations in this area.

    • Word count: 1452

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