Version A. AP* Biology: Photosynthesis. Name: Period

Transcription

1 Name: Period Version A AP* Biology: Photosynthesis Directions: Each of the questions or incomplete statements below is followed by four suggested answers or completions. Select the one that is best in each case and enter the appropriate letter in the corresponding space on the answer sheet. Questions 1-4 Cuvette 1 Cuvette 2 Cuvette 3 Cuvette 4 Phosphate 1 ml 1 ml 1 ml 1 ml Buffer Distilled Water 3 ml 3 ml 3 ml 3 ml + 3 drops DPIP 1 ml 1 ml 1 ml 1 ml Unboiled 3 drops 3 drops Chloroplasts Boiled Chloroplasts 3 drops Students in a biology class performed a controlled experiment designed to test the effect of several factors on the rate of photosynthesis. The 4 cuvettes were assembled as outlined in the table above. DPIP (2, 6 dichlorophenol-indophenol) is a blue dye that becomes colorless when reduced and was used as an electron acceptor in this experiment. A spectrophotometer was used to measure the percentage of light passing through each cuvette (transmittance) every 5 minutes for 30 minutes. During the course of the experiment, cuvettes 2, 3, and 4 were exposed to light, while cuvette 1 was kept in the dark. 1. After 30 minutes, which cuvette would be expected to have the highest level of transmittance? A) Cuvette 1 B) Cuvette 2 C) Cuvette 3 D) Cuvette 4 2. Which of the following molecules is DPIP replacing in this experiment? A) ATP B) H 2 O C) NADP + D) ADP 3. Which of the following best predicts the expected result for Cuvette 1? A) The transmittance level in cuvette 1 will gradually increase over the course of the 30-minute experiment. B) The transmittance level in cuvette 1 will gradually decrease over the course of the 30-minute experiment. C) The transmittance level will increase and then decrease in cuvette 1 over the course of the 30-minute experiment. D) The transmittance level in cuvette 1 will remain the same over the course of the 30-minute experiment. (1)Test Questions are Copyright by College Entrance Examination Board, Prenceton, NJ. All rights reserved. For face-to-fact teaching purposes, classroom teachers are permitted to reproduce the questions. Web or Mass distribution prohibited. (2) AP is registered traemark of the College Entrance Examination Borard. The College Entrance Examination Board was not involved in the production of and does not endorse this product. Permissionis granted of individual classroom teahcers to reproduce the activity sheets and illustation for their own classroom use. Any other type of reproduction of these material is strictly prohibited. 2

2 Version A 4. Time in Minutes % Transmittance 0% 4% 7% 12% 18% 21% 26% The percent transmittance for Cuvette 3, as measured by the spectrophotometer, are shown in the table above. Which of the following most likely explains these results? A) These results are expected since not all of the thylakoid membranes were disrupted by boiling nor were all of the enzymes involved denatured. B) These results are expected results based on the presence of cuvette 3 in the light. C) The chloroplasts were inadequately heated; boiled chloroplasts should have higher levels of transmittance due to the increase in molecular movement. D) The light intensity to which cuvette 3 was exposed was inconsistent during the course of the experiment. 5. Carbon dioxide is passed into a solution of bromothymol blue indicator until the blue acid solution turns yellow. A sprig of elodea, an aquatic plant, is then placed into this yellow solution. After a few hours in the sunlight, the yellow solution contining the elodea turns blue. Which of the following best represents the purpose of this experiment? The purpose of this experiment is to show that A) To demonstrate that oxygen is given off during photosynthesis B) To demonstrate that carbon dioxide is used during photosynthesis C) To demonstrate that carbon dioxide is given off as a byproduct of photosynthesis D) To demonstrate that Bromothymol blue changes to bromothymol yellow under acid conditions 6. The different isotopes of carbon do not differ appreciably in their chemical properties. This is used in chemical and biological research, in a technique called carbon labeling: carbon-14 atoms can be used to replace nonradioactive carbon, in order to trace chemical and biochemical reactions involving carbon atoms from any given organic compound. If plants are grown for several days in an atmosphere containing 14 CO 2 in place of 12 CO 2, which of the followoing is the most likeley result? A) Large amounts of radioactive water will be released from the stomates. B) There will be an increase in the activity of RuBP carboxylase in photosynthetic cells. C) Small amounts of 14 C will be detected in the growing leaves. D) A large increase in 14 C will occur in the starch stored in the roots. 2

3 Version A Questions 7 and 8 Irradiance is a measure of the density of radiation incident on a given surface usually expressed in watts per square centimeter or square meter. The graph above shows the relationship of photosynthetic rate and irradiance (light intensity) as it is influenced by both temperature and carbon dioxide level. 7. According to the graph presented, the greatest rate of photosynthesis occurs when CO 2 is present at A) High concentrations and low temperatures B) Low concentrations and high temperatures C) High concentrations and low irradiance levels D) High concentrations and high irradiance levels 8. Based on the data presented in the graph, which of the following conclusions is most reasonable? A) The rate of photosynthesis at 660 ppm CO 2 is more dependent on temperature than the rate at 330 ppm CO 2. B) Photosynthesis is unaffected by temperature. C) The rate of photosynthesis is inversely proportional to light intensity. D) Attempts to increase photosynthetic yield in field crops should involve the lowering of CO 2 levels. 3

4 Version A 9. Which of the following is an important difference between light-dependent and light-independent reactions of photosynthesis? A) The light-dependent reactions occur only during the day; the light-independent reactions occur only during the night. B) The light-dependent reactions occur in the cytoplasm; the light-independent reactions occur in chloroplasts. C) The light-dependent reactions produce ATP and NADPH; the light-independent reactions use stored energy in ATP and NADPH. D) The light-dependent reactions utilize CO 2 and H 2 O; the light-independent reactions produce CO 2 and H 2 O. 10. A customer observes that a particular potted plant in a restaurant was bigger and greener than other plants in the room. When asked, the owner said that he poured leftover club soda (carbonated water) into that plant s pot every day. Which of the following best explains how the club soda affected that plant s growth? A) The basic ph of the club soda caused the plant to grow rapidly. B) The roots received more moisture, and the leaves were exposed to more CO 2. C) Oxygen bubbles from the club soda oxygenated the grill. D) The roots absorbed the CO 2 necessary for photosynthesis. 11. Photosynthesis is a process used by plants and other organisms to convert the light energy captured from the sun into chemical energy that can be used to fuel the organism's activities. All of the following could reduce the yield of photosynthetic products EXCEPT A) Increased photorespiration B) Fewer Calvin Cycle enzymes C) Reduced carbon dioxide concentrations in the air spaces of the leaf D) Increased frequency of stomata openings 4

5 Version A Questions 12 and 13 Intact chloroplasts are isolated from blended spinach by low-speech centrifugation and are suspended in a cold, protective buffer. If these chilled chloroplasts are illuminated the presence of an oxidized colored dye, one may observe the reduction of the dye as it loses it color. An experiment is set up to determine the optimal reduction potential of the chloroplasts under different wavelengths of light energy. The chloroplast suspensions are individually or simultaneously exposed to the following wavelengths of light by the use of special filters: 550 nanometers (green), 650 nanometers (red), and 700 nanometers (far-red). All exposures are at the same light intensity. The data are given below. 12. According to these data, which of the wavelengths of light energy provides the least energy potential for photosynthesis? A) 550 nm only B) 650 nm only C) 550 and 650 nm D) 650 and 700 nm 13. The greatest reduction of the blue dye by two different wavelengths of light suggests which of the following? A) There are two pigment systems present within the same chloroplast, both absorbing at the same wavelength. B) Different portions of the plant (stems, leaves, etc.) absorb light from different wavelengths. C) Both red and far-red light are transmitted by chloroplasts. D) There are at least two pigment systems with different absorption spectra present within the same chloroplast. 5

6 Version A Questions In a classroom experiment designed to test the effects of various environmental variables on the rate of photosynthesis, each group of students cut 40 identical leaf disks and removed the air bubbles from the spongy mesophyll layer of the leaf disks using the barrel of a syringe as a vacuum; the volume of the air bubbles was replaced with water, which caused the previously-buoyant leaf disks to sink when placed into a cup of water. Twenty leaf disks were placed in a cup containing 200 ml of distilled water, while another twenty leaf disks were placed in a clear cup containing 200 ml of a 0.5% sodium bicarbonate solution. Once all the leaf disks in each cup had sunk to the bottom, both cups were set 30 centimeters away from a 60 watt light source. Students recorded the number of leaf disks that were floating at one-minute intervals until all of the leaf disks in at least one of the cups were floating. The students results are shown in the table below. 14. Based on the data, how long does it take for the half the leaf disks in the bicarbonate solution to rise? A) Between 9 and 10 minutes B) Between 11 and 12 minutes C) Between 10 and 11 minutes D) After 12 minutes 6

7 Version A 15. Which of the following is the most likely explanation for the results of the leaf disks in the cup labeled distilled water? A) The student did not properly remove the air from the leaf disks during the laboratory set-up, which caused none of the leaf disks to rise during the experimental period. B) Since the leaf disks lacked a critical reactant to perform photosynthesis, they did not rise during the experimental period. C) The lack of light prevented the leaf disks from rising. D) The cups were mislabeled; thus, the leaf disks in the cup labeled distilled water were actually immersed in a 0.5% bicarbonate solution, which prevented them from rising. 16. After completing the experiment described above, students designed their own experiments to test various environmental factors on the relative rate of photosynthesis. One student set up two cups, each with 200 ml of 0.5% bicarbonate solution. The bicarbonate solution of one cup was heated to 35º Celsius, while the other was kept 20º Celsius. She cut out 40 identical leaf disks and removed the air from each leaf disks using a syringe plunger to create a vacuum. She then sank twenty leaf disks to the bottom of each cup. She exposed each cup to a 60 watt light source, and kept each cup at a distance of 20 centimeters from the light source. Which of the following best summarizes the question the student was investigating? A) How does light intensity affect the rate of photosynthesis? B) What is the effect of bicarbonate on the rate of oxygen production in spinach? C) How is the rate of photosynthesis affected by temperature? D) Which type of plant is most effective at performing photosynthesis? 7

8 Version A Questions A different student designed an experiment using the same floating disk method. His data is shown on the graph below. 17. Which of the following statements is best supported by this student s data? A) Photosynthesis is affected by the diameter of the leaf disks. B) Chard is more affected by changes in light intensity than other species of plants. C) Kale performs photosynthesis at a slower rate than other plants due to its low number of stomata per cm 2. D) Rates of photosynthesis vary among different species of plants. 18. Based on the data collected, which species of plant had the highest initial rate of photosynthesis? A) ivy B) spinach C) chard D) kale 8

9 Version A 19. Which of the following conclusion statements is best supported based on the experiments outlined in the diagram above? A) The oxygen gas produced during photosynthesis comes from water. B) CO 2 is the source of the oxygen released during photosynthesis. C) NADPH is made during the Calvin Cycle. D) The oxygen released by water is incorporated into organic compounds such as glucose. 20. All of the following are common to C 3 and C 4 photosynthesis EXCEPT A) Photolysis B) Initial step of CO 2 fixation C) Cyclic photophosphorylation D) Noncyclic photophosphorylation 21. Under which of the following conditions would photosynthesis be favored over photorespiration? A) a high concentration of O 2 within the spongy mesophyll of a plant s leaves B) a sunny and windy day in an arid environment C) a high concentration of CO 2 within the spongy mesophyll of a plant s leaves D) the majority of stomata on a plant s leaves are closed 9

10 Version A Questions 22 and 23 A student monitored the cytoplasmic ph of plant leaves over a 36-hour period. The results are shown in the graph below. 22. Which of the following best interprest the data shown above? A) Acidic compounds are produced during the night and day but degraded only at night. B) Acidic compounds are produced during the day. C) Acidic compounds are produced during the day and degraded at night. D) Acidic compounds are produced during the night and degraded during the day. 23. Which of the following biochemical processe is occurring within the leaves of this plant? A) CO 2 is being fixed by PEP carboxylase in the bundle-sheath cells. B) CO 2 is being joined to RuBP by Rubisco in the bundle-sheath cells. C) CO 2 is being joined to RuBP by PEP carboxylase in the bundle-sheath cells. D) CO 2 is being fixed by PEP carboxylase in the mesophyll cells. 10

11 Version A Questions 24 and 25 The graph below shows the relationship between CO 2 uptake by leaves and the concentration of O 2 (percent of atmosphere in growth chambers) and CO 2 (ppm in growth chambers). 24. According to the information presented in the graph, which of the following conditions would produce the most G3P? A) 100 ppm CO 2, 20% O 2 B) 100 ppm CO 2, 80% O 2 C) 200 ppm CO 2, 20% O 2 D) 200 ppm CO 2, 80% O Which of the following explains why there is an inverse relationship between the percent oxygen and the relative carbon dioxide uptake, as shown in the graph above? A) A higher concentration of O 2 causes an increase in the relative CO 2 uptake. B) O 2 is not necessary for photosynthesis. C) As O 2 concentration increases, CO 2 decreases. D) O 2 competes with CO 2 for RuBP caboxylase activity. 26. All of the following occur in cyclic photophosphorylation EXCEPT A) Electrons move along an electron transport chain. B) Electrons in chlorophyll become excited. C) ATP is produced. D) NADPH is produced. 27. Which portion of an illuminated plant cell would you expect to have the lowest ph? A) Thylakoid membrane B) Thylakoid space C) Stroma of chloroplast D) Cytosol 11

12 Version A 28. The photosystem known as P680 and which is involved in only noncyclic phosphorylation has its electron holes filled by electrons from A) Photosystem I B) Photosystem II C) NADPH D) Water 29. In the process of photosynthesis, the production of ATP is directly linked to which of the following? A) The active transport of protons through ATP synthase from the stroma to the thylakoid space. B) The reduction of NADP + to NADPH in the chloroplast. C) The splitting of water in the thylakoid space. D) The diffusion of protons through ATP synthase across the thylakoid membrane. 30. Pigments are chemical compounds which reflect only certain wavelengths of visible light. Examine the absorption spectra for three plant pigments shown above. Which of the following statements best represents the data? A) Green light is well-absorbed by chlorophyll. B) Blue light is reflected by the carotenoids. C) Both red and blue light are absorbed by chlorophyll. D) No light is absorbed at 550 nm. 12

13 Version A 31. About 200 years ago, Jan Baptiste van Helmont performed an experiment regarding the nature of photosynthesis. He wanted to know from where growing plants acquire the raw materials necessary to increase in size. For his experiment, he planted a tree seedling weighing 5 pounds in a barrel filled with 200 pounds of soil. He watered the tree regularly. Five years passed. Van Helmont again weighed the tree and the soil. The tree weighed 169 pounds, 3 ounces. The soil weighed 199 pounds, 14 ounces. Based on his data and your knowledge of photosynthesis, which of the followins most likely explains these results? A) The tree s weight increased after absorbing some of the water van Helmont had added tot he barrel. B) The tree s weight increased after absorbing some of the soil in the barrel. C) The tree s weight increased due to the absorption of both water and soil. D) The tree s weight increased due to a factor other than the soil and water. 32. A desert cactus has been performing photosynthesis all day. After the sun sets, which of the following is the most accurate description of what will occur? A) The Calvin Cycle will continue to operate since it does not require light; G3P will be produced. B) Oxygen will be taken in through the stomata and stored until the morning. C) Oxygen will be produced, but no organic compounds will be synthesized until morning. D) Photosynthesis will stop entirely until the sun rises again. 13

14 AP Biology Photosynthesis Unit Exam Part B Directions: These three questions require numeric answers. Calculate the correct answer for each question, and enter your answer on the grid following each question. Examples of correct entry for the grid-in questions are shown below. The actual questions for this exam begin on the next page. Integer Answer Integer Answer Decimal Answer Fraction Answer / / 1 0

15 Time (minutes) Number of Gas Bubbles 30.0 cm from Elodea 60.0 cm from Elodea A sprig of Elodea was cut and placed in a flask of water containing 3.0 grams of sodium bicarbonate. Next, the apparatus shown above was constructed using a glass funnel that was inverted and placed over the plant specimen. A test tube was then filled completely with water and covered. The test tube was lowered into the water-sodium bicarbonate bath until the mouth of the test tube was under the water s surface. The cover was then removed and the test tube was clamped onto ring stand so that the mouth of the test tube fit over the stem of the glass funnel. Next, a 40 watt light source was set up 30.0 centimeters from the Elodea. Students counted the number of gas bubbles that emerged from the leaves at one-minute intervals and recorded their data over a 10-minute period. The results are shown in the Data Table above. 1. Calculate the difference between the mean numbers of bubbles produced by the Elodea specimen when the 40 watt light source was placed at a distance of 30.0 cm versus 60 cm over the 10 minute time interval. Give your answer to the nearest whole number.

16 2. Calculate the standard deviation for the data set obtained from the Elodea plant set 30 centimeters away from the light source. Record your answer to the nearest hundredth. 3. An experiment was designed to determine the rate of photosynthesis for a population of Algae. A dissolved oxygen probe was placed into the water containing the Algae population and data was collected at 15 minute intervals for a total of 75 minutes. The data is shown below. Time: (minutes) Dissolved Oxygen Concentration: (mg/l) Calculate the rate of net oxygen production between 15 and 45 minutes. Give your answer to the nearest hundredth mg L min.

17 Name: Period Version B AP* Biology: Photosynthesis Directions: Each of the questions or incomplete statements below is followed by four suggested answers or completions. Select the one that is best in each case and enter the appropriate letter in the corresponding space on the answer sheet. 1. All of the following occur in cyclic photophosphorylation EXCEPT A) Electrons move along an electron transport chain. B) Electrons in chlorophyll become excited. C) ATP is produced. D) NADPH is produced. 2. In the process of photosynthesis, the production of ATP is directly linked to which of the following? A) The active transport of protons through ATP synthase from the stroma to the thylakoid space. B) The reduction of NADP + to NADPH in the chloroplast. C) The splitting of water in the thylakoid space. D) The diffusion of protons through ATP synthase across the thylakoid membrane. 3. Carbon dioxide is passed into a solution of bromothymol blue indicator until the blue acid solution turns yellow. A sprig of elodea, an aquatic plant, is then placed into this yellow solution. After a few hours in the sunlight, the yellow solution contining the elodea turns blue. Which of the following best represents the purpose of this experiment? The purpose of this experiment is to show that A) To demonstrate that oxygen is given off during photosynthesis B) To demonstrate that carbon dioxide is used during photosynthesis C) To demonstrate that carbon dioxide is given off as a byproduct of photosynthesis D) To demonstrate that Bromothymol blue changes to bromothymol yellow under acid conditions (1)Test Questions are Copyright by College Entrance Examination Board, Prenceton, NJ. All rights reserved. For face-to-fact teaching purposes, classroom teachers are permitted to reproduce the questions. Web or Mass distribution prohibited. (2) AP is registered traemark of the College Entrance Examination Borard. The College Entrance Examination Board was not involved in the production of and does not endorse this product. Permissionis granted of individual classroom teahcers to reproduce the activity sheets and illustation for their own classroom use. Any other type of reproduction of these material is strictly prohibited. 1

18 Version B Questions 4-7 Cuvette 1 Cuvette 2 Cuvette 3 Cuvette 4 Phosphate 1 ml 1 ml 1 ml 1 ml Buffer Distilled Water 3 ml 3 ml 3 ml 3 ml + 3 drops DPIP 1 ml 1 ml 1 ml 1 ml Unboiled 3 drops 3 drops Chloroplasts Boiled Chloroplasts 3 drops Students in a biology class performed a controlled experiment designed to test the effect of several factors on the rate of photosynthesis. The 4 cuvettes were assembled as outlined in the table above. DPIP (2, 6 dichlorophenol-indophenol) is a blue dye that becomes colorless when reduced and was used as an electron acceptor in this experiment. A spectrophotometer was used to measure the percentage of light passing through each cuvette (transmittance) every 5 minutes for 30 minutes. During the course of the experiment, cuvettes 2, 3, and 4 were exposed to light, while cuvette 1 was kept in the dark. 4. After 30 minutes, which cuvette would be expected to have the highest level of transmittance? A) Cuvette 1 B) Cuvette 2 C) Cuvette 3 D) Cuvette 4 5. Which of the following molecules is DPIP replacing in this experiment? A) ATP B) H 2 O C) NADP + D) ADP 6. Time in Minutes % Transmittance 0% 4% 7% 12% 18% 21% 26% The percent transmittance for Cuvette 3, as measured by the spectrophotometer, are shown in the table above. Which of the following most likely explains these results? A) These results are expected since not all of the thylakoid membranes were disrupted by boiling nor were all of the enzymes involved denatured. B) These results are expected results based on the presence of cuvette 3 in the light. C) The chloroplasts were inadequately heated; boiled chloroplasts should have higher levels of transmittance due to the increase in molecular movement. D) The light intensity to which cuvette 3 was exposed was inconsistent during the course of the experiment. 2

19 Version B 7. Which of the following best predicts the expected result for Cuvette 1? A) The transmittance level in cuvette 1 will gradually increase over the course of the 30-minute experiment. B) The transmittance level in cuvette 1 will gradually decrease over the course of the 30-minute experiment. C) The transmittance level will increase and then decrease in cuvette 1 over the course of the 30-minute experiment. D) The transmittance level in cuvette 1 will remain the same over the course of the 30-minute experiment. Questions 8 and 9 A student monitored the cytoplasmic ph of plant leaves over a 36-hour period. The results are shown in the graph below. 8. Which of the following biochemical processe is occurring within the leaves of this plant? A) CO 2 is being fixed by PEP carboxylase in the bundle-sheath cells. B) CO 2 is being joined to RuBP by Rubisco in the bundle-sheath cells. C) CO 2 is being joined to RuBP by PEP carboxylase in the bundle-sheath cells. D) CO 2 is being fixed by PEP carboxylase in the mesophyll cells. 9. Which of the following best interprest the data shown above? A) Acidic compounds are produced during the night and day but degraded only at night. B) Acidic compounds are produced during the day. C) Acidic compounds are produced during the day and degraded at night. D) Acidic compounds are produced during the night and degraded during the day. 3

20 Version B Questions 10 and 11 Intact chloroplasts are isolated from blended spinach by low-speech centrifugation and are suspended in a cold, protective buffer. If these chilled chloroplasts are illuminated the presence of an oxidized colored dye, one may observe the reduction of the dye as it loses it color. An experiment is set up to determine the optimal reduction potential of the chloroplasts under different wavelengths of light energy. The chloroplast suspensions are individually or simultaneously exposed to the following wavelengths of light by the use of special filters: 550 nanometers (green), 650 nanometers (red), and 700 nanometers (far-red). All exposures are at the same light intensity. The data are given below. 10. The greatest reduction of the blue dye by two different wavelengths of light suggests which of the following? A) There are two pigment systems present within the same chloroplast, both absorbing at the same wavelength. B) Different portions of the plant (stems, leaves, etc.) absorb light from different wavelengths. C) Both red and far-red light are transmitted by chloroplasts. D) There are at least two pigment systems with different absorption spectra present within the same chloroplast. 11. According to these data, which of the wavelengths of light energy provides the least energy potential for photosynthesis? A) 550 nm only B) 650 nm only C) 550 and 650 nm D) 650 and 700 nm 4

21 Version B 12. A customer observes that a particular potted plant in a restaurant was bigger and greener than other plants in the room. When asked, the owner said that he poured leftover club soda (carbonated water) into that plant s pot every day. Which of the following best explains how the club soda affected that plant s growth? A) The basic ph of the club soda caused the plant to grow rapidly. B) The roots received more moisture, and the leaves were exposed to more CO 2. C) Oxygen bubbles from the club soda oxygenated the grill. D) The roots absorbed the CO 2 necessary for photosynthesis. 5

22 Version B Questions In a classroom experiment designed to test the effects of various environmental variables on the rate of photosynthesis, each group of students cut 40 identical leaf disks and removed the air bubbles from the spongy mesophyll layer of the leaf disks using the barrel of a syringe as a vacuum; the volume of the air bubbles was replaced with water, which caused the previously-buoyant leaf disks to sink when placed into a cup of water. Twenty leaf disks were placed in a cup containing 200 ml of distilled water, while another twenty leaf disks were placed in a clear cup containing 200 ml of a 0.5% sodium bicarbonate solution. Once all the leaf disks in each cup had sunk to the bottom, both cups were set 30 centimeters away from a 60 watt light source. Students recorded the number of leaf disks that were floating at one-minute intervals until all of the leaf disks in at least one of the cups were floating. The students results are shown in the table below. 13. Based on the data, how long does it take for the half the leaf disks in the bicarbonate solution to rise? A) Between 9 and 10 minutes B) Between 11 and 12 minutes C) Between 10 and 11 minutes D) After 12 minutes 6

23 Version B 14. Which of the following is the most likely explanation for the results of the leaf disks in the cup labeled distilled water? A) The student did not properly remove the air from the leaf disks during the laboratory set-up, which caused none of the leaf disks to rise during the experimental period. B) Since the leaf disks lacked a critical reactant to perform photosynthesis, they did not rise during the experimental period. C) The lack of light prevented the leaf disks from rising. D) The cups were mislabeled; thus, the leaf disks in the cup labeled distilled water were actually immersed in a 0.5% bicarbonate solution, which prevented them from rising. 15. After completing the experiment described above, students designed their own experiments to test various environmental factors on the relative rate of photosynthesis. One student set up two cups, each with 200 ml of 0.5% bicarbonate solution. The bicarbonate solution of one cup was heated to 35º Celsius, while the other was kept 20º Celsius. She cut out 40 identical leaf disks and removed the air from each leaf disks using a syringe plunger to create a vacuum. She then sank twenty leaf disks to the bottom of each cup. She exposed each cup to a 60 watt light source, and kept each cup at a distance of 20 centimeters from the light source. Which of the following best summarizes the question the student was investigating? A) How does light intensity affect the rate of photosynthesis? B) What is the effect of bicarbonate on the rate of oxygen production in spinach? C) How is the rate of photosynthesis affected by temperature? D) Which type of plant is most effective at performing photosynthesis? 7

24 Version B 16. Which of the following conclusion statements is best supported based on the experiments outlined in the diagram above? A) The oxygen gas produced during photosynthesis comes from water. B) CO 2 is the source of the oxygen released during photosynthesis. C) NADPH is made during the Calvin Cycle. D) The oxygen released by water is incorporated into organic compounds such as glucose. 8

25 Version B Questions 17 and 18 Irradiance is a measure of the density of radiation incident on a given surface usually expressed in watts per square centimeter or square meter. The graph above shows the relationship of photosynthetic rate and irradiance (light intensity) as it is influenced by both temperature and carbon dioxide level. 17. According to the graph presented, the greatest rate of photosynthesis occurs when CO 2 is present at A) High concentrations and low temperatures B) Low concentrations and high temperatures C) High concentrations and low irradiance levels D) High concentrations and high irradiance levels 18. Based on the data presented in the graph, which of the following conclusions is most reasonable? A) The rate of photosynthesis at 660 ppm CO 2 is more dependent on temperature than the rate at 330 ppm CO 2. B) Photosynthesis is unaffected by temperature. C) The rate of photosynthesis is inversely proportional to light intensity. D) Attempts to increase photosynthetic yield in field crops should involve the lowering of CO 2 levels. 9

26 Version B Questions A different student designed an experiment using the same floating disk method. His data is shown on the graph below. 19. Based on the data collected, which species of plant had the highest initial rate of photosynthesis? A) ivy B) spinach C) chard D) kale 21. All of the following are common to C 3 and C 4 photosynthesis EXCEPT A) Photolysis B) Initial step of CO 2 fixation C) Cyclic photophosphorylation D) Noncyclic photophosphorylation 20. Which of the following statements is best supported by this student s data? A) Photosynthesis is affected by the diameter of the leaf disks. B) Chard is more affected by changes in light intensity than other species of plants. C) Kale performs photosynthesis at a slower rate than other plants due to its low number of stomata per cm 2. D) Rates of photosynthesis vary among different species of plants. 10

27 Version B 22. The different isotopes of carbon do not differ appreciably in their chemical properties. This is used in chemical and biological research, in a technique called carbon labeling: carbon-14 atoms can be used to replace nonradioactive carbon, in order to trace chemical and biochemical reactions involving carbon atoms from any given organic compound. If plants are grown for several days in an atmosphere containing 14 CO 2 in place of 12 CO 2, which of the followoing is the most likeley result? A) Large amounts of radioactive water will be released from the stomates. B) There will be an increase in the activity of RuBP carboxylase in photosynthetic cells. C) Small amounts of 14 C will be detected in the growing leaves. D) A large increase in 14 C will occur in the starch stored in the roots. 11

28 Version B Questions 23 and 24 The graph below shows the relationship between CO 2 uptake by leaves and the concentration of O 2 (percent of atmosphere in growth chambers) and CO 2 (ppm in growth chambers). 23. According to the information presented in the graph, which of the following conditions would produce the most G3P? A) 100 ppm CO 2, 20% O 2 B) 100 ppm CO 2, 80% O 2 C) 200 ppm CO 2, 20% O 2 D) 200 ppm CO 2, 80% O Which of the following explains why there is an inverse relationship between the percent oxygen and the relative carbon dioxide uptake, as shown in the graph above? A) A higher concentration of O 2 causes an increase in the relative CO 2 uptake. B) O 2 is not necessary for photosynthesis. C) As O 2 concentration increases, CO 2 decreases. D) O 2 competes with CO 2 for RuBP caboxylase activity. 12

29 Version B 25. About 200 years ago, Jan Baptiste van Helmont performed an experiment regarding the nature of photosynthesis. He wanted to know from where growing plants acquire the raw materials necessary to increase in size. For his experiment, he planted a tree seedling weighing 5 pounds in a barrel filled with 200 pounds of soil. He watered the tree regularly. Five years passed. Van Helmont again weighed the tree and the soil. The tree weighed 169 pounds, 3 ounces. The soil weighed 199 pounds, 14 ounces. Based on his data and your knowledge of photosynthesis, which of the followins most likely explains these results? A) The tree s weight increased after absorbing some of the water van Helmont had added tot he barrel. B) The tree s weight increased after absorbing some of the soil in the barrel. C) The tree s weight increased due to the absorption of both water and soil. D) The tree s weight increased due to a factor other than the soil and water. 26. Which portion of an illuminated plant cell would you expect to have the lowest ph? A) Thylakoid membrane B) Thylakoid space C) Stroma of chloroplast D) Cytosol 27. Which of the following is an important difference between light-dependent and light-independent reactions of photosynthesis? 28. The photosystem known as P680 and which is involved in only noncyclic phosphorylation has its electron holes filled by electrons from A) Photosystem I B) Photosystem II C) NADPH D) Water 29. Photosynthesis is a process used by plants and other organisms to convert the light energy captured from the sun into chemical energy that can be used to fuel the organism's activities. All of the following could reduce the yield of photosynthetic products EXCEPT A) Increased photorespiration B) Fewer Calvin Cycle enzymes C) Reduced carbon dioxide concentrations in the air spaces of the leaf D) Increased frequency of stomata openings 30. Under which of the following conditions would photosynthesis be favored over photorespiration? A) a high concentration of O 2 within the spongy mesophyll of a plant s leaves B) a sunny and windy day in an arid environment C) a high concentration of CO 2 within the spongy mesophyll of a plant s leaves D) the majority of stomata on a plant s leaves are closed A) The light-dependent reactions occur only during the day; the light-independent reactions occur only during the night. B) The light-dependent reactions occur in the cytoplasm; the light-independent reactions occur in chloroplasts. C) The light-dependent reactions produce ATP and NADPH; the light-independent reactions use stored energy in ATP and NADPH. D) The light-dependent reactions utilize CO 2 and H 2 O; the light-independent reactions produce CO 2 and H 2 O. 13

30 Version B 31. Pigments are chemical compounds which reflect only certain wavelengths of visible light. Examine the absorption spectra for three plant pigments shown above. Which of the following statements best represents the data? A) Green light is well-absorbed by chlorophyll. B) Blue light is reflected by the carotenoids. C) Both red and blue light are absorbed by chlorophyll. D) No light is absorbed at 550 nm. 32. A desert cactus has been performing photosynthesis all day. After the sun sets, which of the following is the most accurate description of what will occur? A) The Calvin Cycle will continue to operate since it does not require light; G3P will be produced. B) Oxygen will be taken in through the stomata and stored until the morning. C) Oxygen will be produced, but no organic compounds will be synthesized until morning. D) Photosynthesis will stop entirely until the sun rises again. 14

31 AP Biology Photosynthesis Unit Exam Part B Directions: These three questions require numeric answers. Calculate the correct answer for each question, and enter your answer on the grid following each question. Examples of correct entry for the grid-in questions are shown below. The actual questions for this exam begin on the next page. Integer Answer Integer Answer Decimal Answer Fraction Answer / / 1 0

32 Time (minutes) Number of Gas Bubbles 30.0 cm from Elodea 60.0 cm from Elodea A sprig of Elodea was cut and placed in a flask of water containing 3.0 grams of sodium bicarbonate. Next, the apparatus shown above was constructed using a glass funnel that was inverted and placed over the plant specimen. A test tube was then filled completely with water and covered. The test tube was lowered into the water-sodium bicarbonate bath until the mouth of the test tube was under the water s surface. The cover was then removed and the test tube was clamped onto ring stand so that the mouth of the test tube fit over the stem of the glass funnel. Next, a 40 watt light source was set up 30.0 centimeters from the Elodea. Students counted the number of gas bubbles that emerged from the leaves at one-minute intervals and recorded their data over a 10-minute period. The results are shown in the Data Table above. 1. Calculate the difference between the mean numbers of bubbles produced by the Elodea specimen when the 40 watt light source was placed at a distance of 30.0 cm versus 60 cm over the 10 minute time interval. Give your answer to the nearest whole number.

33 2. Calculate the standard deviation for the data set obtained from the Elodea plant set 30 centimeters away from the light source. Record your answer to the nearest hundredth. 3. An experiment was designed to determine the rate of photosynthesis for a population of Algae. A dissolved oxygen probe was placed into the water containing the Algae population and data was collected at 15 minute intervals for a total of 75 minutes. The data is shown below. Time: (minutes) Dissolved Oxygen Concentration: (mg/l) Calculate the rate of net oxygen production between 15 and 45 minutes. Give your answer to the nearest hundredth mg L min.

34 Name: Period Version C AP* Biology: Photosynthesis Directions: Each of the questions or incomplete statements below is followed by four suggested answers or completions. Select the one that is best in each case and enter the appropriate letter in the corresponding space on the answer sheet. 1. A desert cactus has been performing photosynthesis all day. After the sun sets, which of the following is the most accurate description of what will occur? A) The Calvin Cycle will continue to operate since it does not require light; G3P will be produced. B) Oxygen will be taken in through the stomata and stored until the morning. C) Oxygen will be produced, but no organic compounds will be synthesized until morning. D) Photosynthesis will stop entirely until the sun rises again. (1)Test Questions are Copyright by College Entrance Examination Board, Prenceton, NJ. All rights reserved. For face-to-fact teaching purposes, classroom teachers are permitted to reproduce the questions. Web or Mass distribution prohibited. (2) AP is registered traemark of the College Entrance Examination Borard. The College Entrance Examination Board was not involved in the production of and does not endorse this product. Permissionis granted of individual classroom teahcers to reproduce the activity sheets and illustation for their own classroom use. Any other type of reproduction of these material is strictly prohibited. 1

35 Version C Questions 2 and 3 Intact chloroplasts are isolated from blended spinach by low-speech centrifugation and are suspended in a cold, protective buffer. If these chilled chloroplasts are illuminated the presence of an oxidized colored dye, one may observe the reduction of the dye as it loses it color. An experiment is set up to determine the optimal reduction potential of the chloroplasts under different wavelengths of light energy. The chloroplast suspensions are individually or simultaneously exposed to the following wavelengths of light by the use of special filters: 550 nanometers (green), 650 nanometers (red), and 700 nanometers (far-red). All exposures are at the same light intensity. The data are given below. 2. According to these data, which of the wavelengths of light energy provides the least energy potential for photosynthesis? A) 550 nm only B) 650 nm only C) 550 and 650 nm D) 650 and 700 nm 3. The greatest reduction of the blue dye by two different wavelengths of light suggests which of the following? A) There are two pigment systems present within the same chloroplast, both absorbing at the same wavelength. B) Different portions of the plant (stems, leaves, etc.) absorb light from different wavelengths. C) Both red and far-red light are transmitted by chloroplasts. D) There are at least two pigment systems with different absorption spectra present within the same chloroplast. 2

36 Version C Questions 4 and 5 A student monitored the cytoplasmic ph of plant leaves over a 36-hour period. The results are shown in the graph below. 4. Which of the following biochemical processe is occurring within the leaves of this plant? A) CO 2 is being fixed by PEP carboxylase in the bundle-sheath cells. B) CO 2 is being joined to RuBP by Rubisco in the bundle-sheath cells. C) CO 2 is being joined to RuBP by PEP carboxylase in the bundle-sheath cells. D) CO 2 is being fixed by PEP carboxylase in the mesophyll cells. 5. Which of the following best interprest the data shown above? A) Acidic compounds are produced during the night and day but degraded only at night. B) Acidic compounds are produced during the day. C) Acidic compounds are produced during the day and degraded at night. D) Acidic compounds are produced during the night and degraded during the day. 3

37 Version C Questions 6-8 In a classroom experiment designed to test the effects of various environmental variables on the rate of photosynthesis, each group of students cut 40 identical leaf disks and removed the air bubbles from the spongy mesophyll layer of the leaf disks using the barrel of a syringe as a vacuum; the volume of the air bubbles was replaced with water, which caused the previously-buoyant leaf disks to sink when placed into a cup of water. Twenty leaf disks were placed in a cup containing 200 ml of distilled water, while another twenty leaf disks were placed in a clear cup containing 200 ml of a 0.5% sodium bicarbonate solution. Once all the leaf disks in each cup had sunk to the bottom, both cups were set 30 centimeters away from a 60 watt light source. Students recorded the number of leaf disks that were floating at one-minute intervals until all of the leaf disks in at least one of the cups were floating. The students results are shown in the table below. 6. Based on the data, how long does it take for the half the leaf disks in the bicarbonate solution to rise? A) Between 9 and 10 minutes B) Between 11 and 12 minutes C) Between 10 and 11 minutes D) After 12 minutes 4

38 Version C 7. Which of the following is the most likely explanation for the results of the leaf disks in the cup labeled distilled water? A) The student did not properly remove the air from the leaf disks during the laboratory set-up, which caused none of the leaf disks to rise during the experimental period. B) Since the leaf disks lacked a critical reactant to perform photosynthesis, they did not rise during the experimental period. C) The lack of light prevented the leaf disks from rising. D) The cups were mislabeled; thus, the leaf disks in the cup labeled distilled water were actually immersed in a 0.5% bicarbonate solution, which prevented them from rising. 8. After completing the experiment described above, students designed their own experiments to test various environmental factors on the relative rate of photosynthesis. One student set up two cups, each with 200 ml of 0.5% bicarbonate solution. The bicarbonate solution of one cup was heated to 35º Celsius, while the other was kept 20º Celsius. She cut out 40 identical leaf disks and removed the air from each leaf disks using a syringe plunger to create a vacuum. She then sank twenty leaf disks to the bottom of each cup. She exposed each cup to a 60 watt light source, and kept each cup at a distance of 20 centimeters from the light source. Which of the following best summarizes the question the student was investigating? A) How does light intensity affect the rate of photosynthesis? B) What is the effect of bicarbonate on the rate of oxygen production in spinach? C) How is the rate of photosynthesis affected by temperature? D) Which type of plant is most effective at performing photosynthesis? 9. Which portion of an illuminated plant cell would you expect to have the lowest ph? A) Thylakoid membrane B) Thylakoid space C) Stroma of chloroplast D) Cytosol 10. All of the following occur in cyclic photophosphorylation EXCEPT A) Electrons move along an electron transport chain. B) Electrons in chlorophyll become excited. C) ATP is produced. D) NADPH is produced. 5

39 Version C Questions Cuvette 1 Cuvette 2 Cuvette 3 Cuvette 4 Phosphate 1 ml 1 ml 1 ml 1 ml Buffer Distilled Water 3 ml 3 ml 3 ml 3 ml + 3 drops DPIP 1 ml 1 ml 1 ml 1 ml Unboiled 3 drops 3 drops Chloroplasts Boiled Chloroplasts 3 drops Students in a biology class performed a controlled experiment designed to test the effect of several factors on the rate of photosynthesis. The 4 cuvettes were assembled as outlined in the table above. DPIP (2, 6 dichlorophenol-indophenol) is a blue dye that becomes colorless when reduced and was used as an electron acceptor in this experiment. A spectrophotometer was used to measure the percentage of light passing through each cuvette (transmittance) every 5 minutes for 30 minutes. During the course of the experiment, cuvettes 2, 3, and 4 were exposed to light, while cuvette 1 was kept in the dark. 11. Time in Minutes % Transmittance 0% 4% 7% 12% 18% 21% 26% The percent transmittance for Cuvette 3, as measured by the spectrophotometer, are shown in the table above. Which of the following most likely explains these results? A) These results are expected since not all of the thylakoid membranes were disrupted by boiling nor were all of the enzymes involved denatured. B) These results are expected results based on the presence of cuvette 3 in the light. C) The chloroplasts were inadequately heated; boiled chloroplasts should have higher levels of transmittance due to the increase in molecular movement. D) The light intensity to which cuvette 3 was exposed was inconsistent during the course of the experiment. 12. After 30 minutes, which cuvette would be expected to have the highest level of transmittance? A) Cuvette 1 B) Cuvette 2 C) Cuvette 3 D) Cuvette Which of the following molecules is DPIP replacing in this experiment? A) ATP B) H 2 O C) NADP + D) ADP 6

40 Version C 14. Which of the following best predicts the expected result for Cuvette 1? A) The transmittance level in cuvette 1 will gradually increase over the course of the 30-minute experiment. B) The transmittance level in cuvette 1 will gradually decrease over the course of the 30-minute experiment. C) The transmittance level will increase and then decrease in cuvette 1 over the course of the 30-minute experiment. D) The transmittance level in cuvette 1 will remain the same over the course of the 30-minute experiment. Questions 15 and 16 Irradiance is a measure of the density of radiation incident on a given surface usually expressed in watts per square centimeter or square meter. The graph above shows the relationship of photosynthetic rate and irradiance (light intensity) as it is influenced by both temperature and carbon dioxide level. 15. Based on the data presented in the graph, which of the following conclusions is most reasonable? A) The rate of photosynthesis at 660 ppm CO 2 is more dependent on temperature than the rate at 330 ppm CO 2. B) Photosynthesis is unaffected by temperature. C) The rate of photosynthesis is inversely proportional to light intensity. D) Attempts to increase photosynthetic yield in field crops should involve the lowering of CO 2 levels. 7

41 Version C 16. According to the graph presented, the greatest rate of photosynthesis occurs when CO 2 is present at A) High concentrations and low temperatures B) Low concentrations and high temperatures C) High concentrations and low irradiance levels D) High concentrations and high irradiance levels Questions A different student designed an experiment using the same floating disk method. His data is shown on the graph below. 17. Which of the following statements is best supported by this student s data? A) Photosynthesis is affected by the diameter of the leaf disks. B) Chard is more affected by changes in light intensity than other species of plants. C) Kale performs photosynthesis at a slower rate than other plants due to its low number of stomata per cm 2. D) Rates of photosynthesis vary among different species of plants. 18. Based on the data collected, which species of plant had the highest initial rate of photosynthesis? A) ivy B) spinach C) chard D) kale 19. All of the following are common to C 3 and C 4 photosynthesis EXCEPT A) Photolysis B) Initial step of CO 2 fixation C) Cyclic photophosphorylation D) Noncyclic photophosphorylation 8