Ch 10 Ap Classroom
Carbohydrate-synthesizing reactions of photosynthesis directly require
products of light reactions
The energy required to run the Calvin cycle reactions of photosynthesis comes from which two substances produced during the light-dependent reactions?
ATP and NADPH
A researcher claims that increased atmospheric carbon dioxide levels cause increased growth rates in plants. Which of the following statements best supports the researcher's claim?
Atmospheric carbon dioxide is the raw material for photosynthesis, which plants rely on for producing sugars and other organic compounds.
For following group of questions first study the description of the situation and diagrams and then choose the one best answer to each question following it and fill in the corresponding oval on the answer sheet. A student studied the effects of light intensity on oxygen production in green algae. The algae were suspended in water inside a sealed glass jar, and the jar was placed into a constant-temperature, lightproof box containing a light source. A probe was inserted into the jar to record the concentration of oxygen. The probe was connected to a recording device. The setup is shown below. The student decreased the intensity of the light hourly and recorded the corresponding changes in oxygen concentration. The graph below shows the results from the recording device. An increase in the rate of oxygen production by algae would be accompanied by a comparable increase in the rate of production of which of the following substances?
C6H12O6
Process in which carbon from CO2 is incorporated into organic molecules
Calvin Cycle
What most likely causes the trends in oxygen concentration shown in the graph above?
D) Photosynthesis produces more oxygen than is consumed by respiration during the day.
The chemical reaction for photosynthesis is 6CO2 + 12H2O + light energy → → C6H12O6 + 6O2 + 6H2O If the input water is labeled with a radioactive isotope of oxygen, 18O, then the oxygen gas released as the reaction proceeds is also labeled with 18O. Which of the following is the most likely explanation?
During the light reactions of photosynthesis, water is split, removing electrons and protons, and oxygen gas is released.
The O2 released during photosynthesis comes from
H2O
Which of the following questions is most relevant to understanding the Calvin cycle?
How is ATP used in the formation of 3-carbon carbohydrates?
Germination seeds need
Light
Process in which O2 is released as a by-product of oxidation-reduction reactions
Light dependent reactions of photosynthesis
If O2 production goes down in a organism, what process is decreased
Photosynthesis
Which of the following is an important difference between light-dependent and light-independent reactions of photosynthesis?
The light-dependent reactions produce ATP and NADPH; the light-independent reactions use energy stored in ATP and NADPH.
If the level of oxygen stays the same then
The rate of photosynthesis is the same as respiration
Which of the following statements is true about the Krebs (citric acid) cycle and the Calvin (light-independent) cycle?
They both are carried out by enzymes located within an organelle matrix.
The carbon 'that makes up organic molecules in plants is derived directly from
carbon fixed in photosynthesis
A student placed 20 tobacco seeds of the same species on moist paper towels in each of two petri dishes. Dish A was wrapped completely in an opaque cover to exclude all light. Dish B was not wrapped. The dishes were placed equidistant from a light source set to a cycle of 14 hours of light and 10 hours of dark. All other conditions were the same for both dishes. The dishes were examined after 7 days, and the opaque cover was permanently removed from dish A. Both dishes were returned to the light and examined again at 14 days. The following data were obtained. For Dish A, the Germinated seeds after 7 days are 12 and at day 14 are 20. The Green-leaved seedlings after 7 days are 0 and at day 14 are 14. The Yellow-leaved seedlings after 7 days are 12 and at day 14 are 6. The Mean stem length below first set of leaves after 7 days is 8 millimeters and at day 14 is 9 millimeters. For Dish B, the Germinated seeds after 7 days are 20 and at day 14 are 20. The Green-leaved seedlings after 7 days are 15 and at day 14 are 15. The Yellow-leaved seedlings after 7 days are 5 and at day 14 are 5. The Mean stem length below first set of leaves after 7 days is 3 millimeters and at day 14 is 3 millimeters. According to the results of this experiment, germination of tobacco seeds during the first week is
increased by exposure to light
A student placed 20 tobacco seeds of the same species on moist paper towels in each of two petri dishes. Dish A was wrapped completely in an opaque cover to exclude all light. Dish B was not wrapped. The dishes were placed equidistant from a light source set to a cycle of 14 hours of light and 10 hours of dark. All other conditions were the same for both dishes. The dishes were examined after 7 days, and the opaque cover was permanently removed from dish A. Both dishes were returned to the light and examined again at 14 days. The following data were obtained. For Dish A, the Germinated seeds after 7 days are 12 and at day 14 are 20. The Green-leaved seedlings after 7 days are 0 and at day 14 are 14. The Yellow-leaved seedlings after 7 days are 12 and at day 14 are 6. The Mean stem length below first set of leaves after 7 days is 8 millimeters and at day 14 is 9 millimeters. For Dish B, the Germinated seeds after 7 days are 20 and at day 14 are 20. The Green-leaved seedlings after 7 days are 15 and at day 14 are 15. The Yellow-leaved seedlings after 7 days are 5 and at day 14 are 5. The Mean stem length below first set of leaves after 7 days is 3 millimeters and at day 14 is 3 millimeters. Additional observations were made on day 21, and no yellow-leaved seedlings were found alive in either dish. This is most likely because
yellow-leaved seedlings were unable to convert light energy to chemical energy