Photosynthesis- SAQs.docx

Questions 1. Define photosynthesis. Photosynthesis is the way in which plants make their own food using light energy. 2. Write the word equation for photosynthesis. Carbon dioxide + water glucose and oxygen 3. Write the chemical equation for photosynthesis.            6...

Questions 1. Define photosynthesis. Photosynthesis is the way in which plants make their own food using light energy. 2. Write the word equation for photosynthesis. Carbon dioxide + water glucose and oxygen 3. Write the chemical equation for photosynthesis.            6CO~2~ + 6H~2~O                C~6~H~12~O~6~ + 6O~2~  4. Give both names of the first stage of photosynthesis. The light stage and the light dependent stage 5. What is photolysis? When water is split into high energy electrons, hydrogen protons and oxygen by light.  6. Name pathway 1 of the light stage. Cyclic photophosphorylation 7. Name pathway 2 of the light stage. Non-cyclic photophosphorylation 8. Name the three products of the light stage.        ATP, NADPH, Oxygen 9. Give both names of the second stage of photosynthesis. The dark stage and the light independent stage 10. Why can the dark stage not happen without the light stage? The products of the light stage are used to fuel the reactions of the dark stage.  11. Where does photosynthesis take place? In the chloroplast 12. Which of the light stage and the dark stage are enzyme controlled? The dark stage 13. What is the role of carbon dioxide in photosynthesis? It provides the carbon 14. What does ATP stand for? Adenine triphosphate  15. Name one method by which the rate of photosynthesis can be increased? The use of greenhouses to grow plants. **[Photosynthesis Questions:]** 1. Where did the light source come from? The lamp 2. What factor did you keep constant during the experiment and how? Temperature and use of a water bath with a thermometer. 3. How did you vary the light intensity throughout the experiment? By moving the lamp by 10cm at each new run of the experiment 4. Why is elodea a suitable plant for this experiment? The number of bubbles coming from the stem per minute can be easily counted? 5. How did you measure the rate of photosynthesis? By counting the number of bubbles coming from the stem of the plant per minute. 6. Each time the light intensity is varied the rate of photosynthesis could not immediately be measured. Why? The experiment needed to reach equilibrium before the rate of photosynthesis could be measured. 7. How did you keep the level of carbon dioxide stable? Prior to adding the elodea, a graduated cylinder is taken and ¾ filled with a premade 0.002% Sodium Hydrogen Carbonate and water solution. 8. Describe the graph for the experiment. Initially, the graph increases proportionally with light intensity. However, as the light intensity becomes greater the graph levels off as the plant becomes saturated in light.  9. How did you cut the plant? Using a scalpel, cut the stalk of the Elodea at an angle near the base of the stalk.