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International Baccalaureate: Biology

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  1. Experiment Plan. What effect does 2 minute of each leg muscle stretch (hamstring, calf stretch, thigh stretch) before exercise have on the rate of increase of heart rate during the exercise?

    By definition, stretching is movement of a joint or muscle to full extension by lengthening the tissues. People stretch to increase their flexibility and range of motion; they stretch before intense work out sessions and to prevent injuries and rehabilitation. Stretching leg muscles before exercise leads to an increase in blood flow. This leads to a higher requirement of oxygen and this causes a higher than normal heart rate before the actual exercise. Since the blood is already flowing at a quicker rate the heart rate should increase at a slower rate.

    • Word count: 886
  2. Therapeutic Uses of Stem Cells

    The major purpose of the production of embryonic stem cells is for therapeutic treatments on living organisms such as humans or animals. Scientists that attain the right conditions for these cells are able to cultivate them for repair or replacement of injured, diseased, or dead organs and tissues.

    • Word count: 466
  3. How does the concentration of hydrogen peroxide affect the time (s) it takes the enzyme catalase to decompose it into water and oxygen gas?

    Controlled: 1. Mass (in grams) of pureed cow?s liver (catalase) 1. Each test will use 10 grams of pureed cow?s liver, containing the enzyme catalase. 2. If uncontrolled, the reaction time could be either increased or decreased because of the changed amount of the catalyst, create imprecise data. 1. Temperature 1. The lab will be kept at a constant temperature of 20 degrees Celsius. 2. Temperature is a primary factor affecting both enzyme activity and reaction speed.

    • Word count: 458
  4. Is the rate of passive transport through potato slices and saltwater and distilled water significantly different?

    Electronic balance (Error: ±.01g) 3. Table Salt (NaCl) 4. Potato 5. Corer 6. Knife 7. Distilled Water 8. Graduated Cylinder (±1mL) 9. Spoon 10. Balance paper 11. Ruler (± .1 mm) 12. Cups 13. 10 Plastic bags Procedure: 1. Core potatoes and cut them into 20 mm lengths. Cut 100 slices and put 10 slices in each plastic bag. 2. Set out 10 cup (5 for salt, 5 for water) and label them Cup 1 Distilled Water, Cup 1 Saltwater, etc.

    • Word count: 757
  5. Finding the vitamin C content of a lemon

    Then we had to determine the volume of lemon juice that is needed to decolorize the same amount PCPIP. This provided us with the concentration of vitamin C in the lemon juice. RESULTS We got separated into four groups and the results of all of the groups were in the end combined and the average was calculated. Our first result was that the indicator will change the color if we add 0.75 ml of 0.1 % C vitamin solution to it.

    • Word count: 408
  6. Biology SL Lab Report - Genetically Modified Crops and Health

    For my experiment to go through, I will need to travel to India. India is one of the cradles of rice cultivation and, also, the second most populated country in the world. Half of the population is fed by rice daily. Favorable locations for rice cultivation are moist and damp places near rivers. Because of this, the delta of the Cauvery river in south-east India is a good location for planting seedlings of rice plants. The rice in this area is perennial, meaning it lives long and is capable of re-growing without reseeding, year long.

    • Word count: 995
  7. 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
  8. 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
  9. 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
  10. 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
  11. 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
  12. 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
  13. 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 .....

    • Word count: 606
  14. 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
  15. 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
  16. Is there such thing as too much mammography?

    If removed at this stage they cannot harm patients.[4] Dr. H. Gilbert Welsh and Brittney A. Frankel, two Dartmouth researchers, did a study and concluded that even considering these benefits; it is true that there are a relatively low percentage of women who have found mammography useful. Dr. Welsh?s notes that of 138,000 women who are diagnosed with breast cancer due to mammography; 120,000 to 134,000 are not helped by the screening. ?The presumption is that anyone who has had cancer detected has survived because of this test, ? said Dr.

    • Word count: 972
  17. Assessing Water Quality in a Stream by Chemical Means

    Measuring turbidity: The turbidity was measured using a transparent plastic bottle. A turbidity disc was put on its surface and it was then filled with water. The water was then compared to the turbidity disc?s color and thus the turbidity was determined. 1. Measuring flow velocity: The flow velocity was measured using paper boats. A 10 meter long distance was measured and the boat was taken to starting point of the measured distance. Then, the speed of the boat was calculated.

    • Word count: 733
  18. The consequences of introducing alien species into a ecosystem

    Many alien species are transferred into marine ecosystems through the ballast water transported during commercial shipping operations. Alien species are often introduced into freshwater ecosystems such as estuaries, rivers, lakes and streams by humans discarding animals or plants formerly held in captivity. In some cases, species used as bait can invade freshwater ecosystems. Well-known invasive species include the Northern Snakehead fish, the Zebra mussel, the Sea Lamprey and the Asiatic Clam, Corbicula fluminea.

    • Word count: 425
  19. 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
  20. 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
  21. 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
  22. 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
  23. 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

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