EOC Practice

1. EOC Practice

2. Page 10 1. People sweat to help maintain body temperature. What type of feedback happens when sweating regulates body temperature. • Negative feedback because sweating decreases body temperature. Note: Homeostasis—in a system feedback is when one factor causes another to increase (positive) or decrease (negative)

3. Page 10 • Plants use nitrogen to make proteins. What is present in the soil that makes nitrogen directly available to plants? • Bacteria Note: basic elements N, O, C are recylced through an ecosystem. N from the air is taken by bacteria where is it available as nitrogen in the soil (like fertilizer).

4. Page 14 3. How could M and K be more certain the results of their experiment are more reliable? • Repeat the same experiment in the same way. Note: To check reliabilty it is important that everything tested remains the same. Repeat the experiment. If you changed anything else, you would be testing something else.

5. 4. Write a conclusion for this controlled experiment Question: What is the effect of acidity of potato juice on the volume of foam produced when hydrogen peroxide is added to potato juice? In your conclusion be sure to • answer the experimental question (circle) • Include supporting data from the table(Sq) • explain how these data support your conc.(UL) • Provide a scientific explanation for the trend in the data (shade)

6. answer the experimental question If you increase the pH of the potato juice from 6 to 7 then to 8 the amount of foam produced increases with each step. However at pH 9 the amount of foam produced decreases to less than that of pH 7.

7. Include supporting data from the table At pH 6 an average of 24 ml of foam was produced while pH 7 and pH 8 produced 35 and 42 respectively. However, at pH 9, the volume of foam produced dropped to 30 ml.

8. explain how these data support your conclusion The data show that as the pH of the solution increases from 6,7,8 the volume of Foam also increases from 24,35,42. However, when the pH is increased to 9 only 30 ml of foam were produced.

9. Provide a scientific explanation for the trend in the data • The enzyme that releases oxygen from hydrogen peroxide is helped by higher pH. However, pH 9 is too high and this level inhibits the function of the enzyme. • At 9, the pH is too high and this level damages the potato so that enzyme cannot be released • A high pH of 9 interacts with the hydrogen perioxide and prevents the release of oxygen.

10. 5 What did Mike and Kelsey do to make the results of their experiment valid? • B. Calculated the average volume of foam for each acidity. Note: Validity in an experiment has a similar meaning to accuracy. If I wanted to accurately determine how fast you could run a mile my accuracy would increase the more times you ran it. Eventually, an average would be a more valid measure that if you only ever ran it once.

11. What is the effect of the temperature of potato juice on the time for bubbling to stop after hydrogen peroxide is added. Procedure: • Place 10ml of potato juice in 6 test tubes • Set two test tubes aside and place 4 in a water bath in a 250ml beaker. • Place the water bath on a hot plate and beginning heating. Place a C thermometer in the water bath • Label 6 graduated cylinders 2 at 20 degrees 1 at 40 degrees, 1 at 60 degrees. 1 at 80 degrees and 1 at 100 degrees.

12. 5. pour 5ml of H2O2 into a room temperature potato juice and record how many seconds bubbles continue to be formed. Record. • 6. when the temperature of the water bath reaches 40 remove one test tube of potato juice, add 5ml of H2O2 and record the time of bubbles. • 7. Repeat step six for 60, 80, and 100 degrees. • 8. Repeat using the second room temperature test tube of potato juice.

13. Controlled variables • 1. Controlled for temperature: one test had no increase in heat. • 2. Controlled for time one test tube had no heat but was tested after the same amount of time as the longest.

14. variables • Manipulated (independent): temperature of potato juice • Responding (dependent): time it took bubbles to stop.

15. Page 19 7. The green pepper plant has proteins that control the process of making glucose. How does the plant obtain these proteins? • The plant makes the proteins using the instructions in DNA • Becky and Juan want to increase the mass of food produced in the school garden. Which of the following questions could lead to a possible solution to this problem? c. Which plants product the most protein

16. Page 20 • What is the role of cellular respiration in plants? • To produce ATP

17. Becky and Juan used a greenhouse as a model of a garden ecosystem to predict effects of amount of sunlight on green pepper production in a garden ecosystem Describe two way the greenhouse model may lead to unreliable predictions about the effects of amount of sunlight on green pepper production in a garden ecosystem.

18. One way A greenhouse is kept at a constant temperature while the outdoor temperature varies a great deal. The warm temperature could make the pepper grow faster. A greenhouse can be kept at a constant humidity while it varies greatly outdoors. A higher constant humidity could increase pepper growth faster than outside.

19. 11. What caused the increase in the average beak size of the finch population after the 1977 drought? • Finches with bigger beaks were able to survive and reproduce.

20. Scientists must be careful that their activities in an ecosystem do not introduce any new organisms into that ecosystem. What might be an effect on the finch population Daphne major if a new bid species were brought to the island. C. The finch population would decline due to competition.

21. Before the drought. Daphne Major had 720 finches living on 80 acres of land. What was the population density of finches on Daphne Major? • 720 ÷ 80= 9 finches per acre

22. Why are the offspring of flowering plants genetically different from the parent plants? • Sexual reproduction produces offspring with new combinations of genes • What part of the cell produces ATP for the blueberry plant to grow? • A. Mitochondria

23. Blueberries contain sugars like glucose. What is the source of carbon for the glucose in blueberries? B. Carbon Dioxide in the air

24. Jose and Tasha want to improve the soil in the garden by increasing the population of worms in the soil. Describe how to begin solving this problem. • Research the problem • Under what environmental conditions do worms grow the best • What do worms eat—what diseases do they get • c. Are the different types of worms?

25. Explore idea Raise trial populations of worms in different soils that contain different nutrients. Keep a record of their numbers. Visit different gardens and locations—sample worm poplation and worm size. Figure out what worms like and need. Try sample enriched environments.

26. What is Reliability? • The idea behind reliability is that any significant results must be more than a one-off finding and be inherently repeatable. • Other researchers must be able to perform exactly the same experiment, under the same conditions and generate the same results. This will reinforce the findings and ensure that the wider scientific community will accept the hypothesis. • Without this replication of statistically significant results, the experiment and research have not fulfilled all of the • Read more: Validity and Reliability - How to Know if the Research is Correct?