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International Baccalaureate: Biology

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  • Marked by Teachers essays 11
  • Peer Reviewed essays 1
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  1. Biology- Extended essay. For this research, I investigated the effects of DDT and an Azo-Dye on the opercular movement of Mrigal (Cirrhinus cirrhosus) a fresh water fish.

    From the results that I recorded, and observed I can say that DDT, the Azo-Dye and the mixture of these two toxins reduce the opercular movement of Mrigal. The graphs show a clear trend of decline in the opercular movement. The results of the three investigations helped me conclude that DDT and the Azo-Dye both have a similar affect on the opercular movement of the fish and that the mixture of these two toxins is collectively more dangerous. These toxins affect the fishes by reducing their opercular movement with an increase in concentration.

    • Word count: 6440
  2. Testing the effect of characteristics of leaves on the transpiration rate of * Rubiaceae, Verbenaceae, Oleaceae, and Rutaceae

    The first stage is called photolysis. Light energy is to split water into one oxygen and two hydrogen atoms. Oxygen as waste product leaves a plant and ATP energy is also produced by absorbed light (Clegg, 2007). The second and last step is carbon fixation. In this part, carbon dioxide (CO2), hydrogen atoms from photolysis, and energy from ATP together form organic molecules of sugar, or glucose (Clegg, 2007). As mentioned before, oxygen leaves a plant. Not only oxygen but also water leaves the plant. More exactly, water evaporates from the plant mainly at leaves.

    • Word count: 4469
  3. In this extended essay I am looking at the effect of different kind of music on same species of plant. I will take Chickpeas (gram seeds) to perform a lab showing the effect of music on them. I will choose four different situations to see the effect of mu

    First I will take twenty seeds of chickpeas and divide it into four groups. Then I will germinate them placing them in cotton, soaked in water. At the same time I will write the name of the music on each group and will play the same kind of music written on the plate. I will play music on each group of plant for three hours a day. I will keep the plants that come in no sound group in an isolated room where all the conditions are similar to others but sound cannot be heard from there.

    • Word count: 5724
  4. 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
  5. 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
  6. 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
  7. 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
  8. 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
  9. 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
  10. 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
  11. 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
  12. Research Project . Should Research Into Biological Warfare Continue?

    While effective against the airborne spores antibiotics do not reduce the amount of virulence factor in victims. Even with antibiotic treatment, the virulence factors continue to cause damage within the body. Anthrax has seldom been released from the labs; this means that no one really knows how much potential it has as a weapon of mass destruction it has. However, it is still one of the most feared bioterrorist weapons around. Anthrax can be grown in a lab, and stored in a spore form for long periods of time (Generations).

    • Word count: 3404
  13. Genes of fruit fly practical write up

    This is because they both aren't sex related and they had very similar numbers for both male and female wild and black colour. In both crosses Wild type colour was dominant and ebony and black recessive, as when the wild type body colour has been added together there is roughly three times as many as there are ebony coloured body flies. Sable Coloured Body Table 2.1.4 Phenotype Observed Wild type 896 Sable body 296 Total 1192 Sable coloured body, Tan Coloured body and Yellow coloured body are all also very similar.

    • Word count: 3616
  14. The effect of toliet cleaning products on E-coli

    From a combination of contaminated surfaces and unsatisfactory hygienic practise the bacteria can be transferred from person to person. To minimize the transmittance of e coli from person to person in bathrooms many toilet cleaning agents have been developed. These come in many brands and varieties boosting characteristics such as fresh smells or longevity. But a common feature with all toilet cleaning products is that they remove harmful germs. Bacteria divide by the process of binary fission. In this process the bacterial DNA strand is replicated and then the cell is split, resulting in two identical cells.

    • Word count: 5204
  15. What is the effect of different body positions i.e. lying down, sitting and standing on the blood pressure?

    Literature values for the blood pressure of participants in a lying position is 115/70, 120/79 for participants sitting down and 121/78 for participants standing (OneTwentyOverEighty, 2007), where the lower value represents the diastolic and the higher the systolic pressure. Based on this literature, it is predicted that the blood pressure of the participants will be the highest when participants are in a standing position, second highest when sitting down on a chair and the lowest when lying down. Variables: Independent: the body position in which the participants remained in for a period of 2 minutes (before blood pressure was measured)

    • Word count: 3791
  16. Research Question (RQ) How does the position of the arm (cuff) in relation to the heart, affect the blood pressure[1] of non-diabetic, female, 16 year olds, in terms of Systolic Pressure[2] and Diastolic Pressure[3]?

    It is expected that the systolic and diastolic pressures values in this experiment, will change in a similar fashion to the SpO2 values in the Pulse Oxygenation experiment, as a result of moving the monitored arm. Thus it is hypothesised that when the monitored arm is held above the heart, the systolic and diastolic pressures will be lower than the control. 'The systolic and diastolic blood pressure measured with the arm perpendicular to the body was significantly lower than with the arm in a parallel position.'

    • Word count: 4586
  17. The effect of pvc piping on the breathing/heart rates of male year 12 students

    Providing that airflow is not simply restricted breathing through a straw is still very possible, however breathing becomes considerably more difficult. This will result in the frequency of breaths lowering. This consequently means that less oxygen will enter the body. This could in turn increase human heart rate (Blurtit, 2009). The human circulatory system is not a flexible apparatus. It is system of interconnected tubing that follows a predetermined pattern. In short that oxygen to surface area distribution ratio of the human body never changes.

    • Word count: 5810
  18. Extended Essay- How is production of carbon dioxide (CO2) during digestion affected by the type of carbohydrate consumed, in reference to artificial versus natural?

    This paper specifically focuses on the affects of digesting carbohydrates, and its effect on the release of carbon dioxide and other gases. The problem might lie just with the fact of eating natural or artificial carbohydrates. The differences between the two forms of carbohydrates will be singled out, and reasons for the release of carbon dioxide will become apparent. The question to begin with is: How is production of carbon dioxide (CO2) during digestion affected by the type of carbohydrate consumed, in reference to artificial versus natural?

    • Word count: 4260
  19. Biology Lab - frequency of cell division in animal and plant cell

    Each stages of mitosis cycle were drawn on the diagram. The actual length, width and the magnification of the cell and the frequency of the mitosis were recorded and calculated on the back of the diagram. At the end, the calculated magnification of the cell was recorded on the bottom right of the diagram. The length and width of the cell and how many times it would fit across the width and the length of the field of view were estimated and recorded on the paper. To remove the slide, the nosepieces were rotated back to low-power and the coarse adjustment was used to put the stage further away from the objective lenses.

    • Word count: 3043
  20. Bio lab - Oxygen Consumption in germinating and non-germinating seeds

    10 seeds were placed in the test tubes and a layer of non-absorbent cotton was placed on top of the KOH solution cotton. 5. For equal volume, beads were added to each of the test tubes with the dormant seeds since dry peas take up less space than the same quantity of germinating peas. The test tubes were capped with the stopper fitted with a pipette, tip pointing outwards. 6. The pipette was put into the water to find out the consumption of the oxygen.

    • Word count: 6392
  21. Ecology Open Investigation Does the geographic location affect the biotic and abiotic factors in Brown Lake and 18 Mile Swamp located at North Stradbroke Island.

    [3] Beside the swamp is a four wheel drive track that extends from the Causeway. This track was built for vehicles. Because Brown Lake and 18 Mile Swamp is located in different parts of the island, in this investigation, biotic and abiotic features of Brown Lake and 18 Mile Swamp will be compared to see if the geographical location affect the features of the site. Abiotic features such as colour, turbidity, oxygen levels, pH level, salinity, nitrites, nitrates and temperature will be sampled and tested in this investigation.

    • Word count: 6399
  22. Lung Capacity Fitness Level

    [6] Vital Capacity = IRV (inspiration) + ERV (expiration) Diagram 1.1: Graph showing the different breathing activities [7] There are several factors which affect one's potential lung capacity. Factors such as: * Gender - as males have larger lung capacity than females * Height of person - the taller the person is the tendency that they will have a larger lunch capacity then a shorter height person * Smoking - smoking damages the lungs and slowly diminishes its functions thus causing the lungs to become weaker * Exercise - athletes have a larger lung capacity then non-athletes * Breathing illnesses - eg; asthma can affect one's breathing activity as the lungs are weak and have difficulty handling rapid changes in physical breathing activity (such as sprinting)

    • Word count: 6468
  23. Allelopathy. Open Investigation Will increasing the number of allelopathic sunflower plants effect the height growth of a non-allelopathic bean plant when the two types of plants are grown next to one another?

    * Reduce the ability of plants to compete with allelopathic plants which are excreting the chemicals Plants that are under stress from such things as the existence of pests and diseases, less than optimum access to nutrients, sun or moisture, possess a higher risk of being eliminated by allelopathic plants. Diagram 1.1: Plant external structure [8] Allelopathic chemicals can be released from any part of the plant, it merely depends of what type of plant it is. Allelochemicals can be released from can plants' leaves, flowers, roots, fruits, or stems.

    • Word count: 7463
  24. The effect on osmosis on the egg shell

    VARIABLES Apparatus Units Range INDEPENDENT VARIABLE 1. Different concentration of salt solution - [%] 0-10 % DEPENDENT VARIABLE 1. Mass change of eggs* Electronic balance [g] [�0.01 g] *thanks to this, indirectly mass change In eggs will be measured Possible effect(s) on result UNCONTROLLED VARIABLE 1. Size of air cell inside the egg It affects degree of egg's immersion and may affect process of osmosis as it reduces contact surface between surrounding and content of egg (which is separated by semi-permeable membrane 2.

    • Word count: 3500
  25. Reaction Time

    Introduction To be able to participate in certain sports activities one needs to, to some extent, be fit. Strength, endurance, flexibility, balance and agility are some of the factors which might decide who wins a game of some sport. Another factor that contributes to having an advantage in sports is a fast reaction time. Reaction time is the time between a stimulus and the beginning of the reaction to given stimulus.1 The time to respond to the stimuli, which is the time it takes to carry out an action or the movement speed to carry out the reaction, is not included in the reaction time.

    • Word count: 5267

IB Biology is the study of living organisms. The four basic concepts which run through the course are: evolution, equilibrium within systems, universality versus diversity, and structure and function. These concepts give the student a strong foundation upon which other detailed knowledge can be built. You will also be completing a significant amount of practical work and an experimental approach is strongly emphasised.

Assessment is both externally and internally organised. The external examinations are a mixture of multiple-choice, short answer and extended answer tests.The extended answer examinations require you express yourself in a concise and scientific manner and some great examples of these IB Biology essays can be found on Marked by Teachers. Science can bring enormous benefits to societies and you will be encouraged to become a responsible and ethically minded scientist.


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