Chapter 10
Photosynthesis
Vocabulary: photosynthesis, autotroph, heterotroph, chlorophyll, mesophyll, stroma, thylakoid, light reactions, Calvin cycle, NADP+, photophosphorylation, carbon fixation, electromagnetic spectrum, wavelength, photons, spectrophotometer, absorption spectrum, action spectrum, carotenoids, photosytem, reaction-center complex, light harvesting complex, primary electron acceptor, linear electron flow, cyclic electron flow, photorespiration, bundle-sheath cells, C3 plants, C4 plants, CAM plants
Objectives:
After attending lectures and studying the chapter, the student should be able to:
1. Distinguish between autotrophic and heterotrophic modes of nutrition.
2. Distinguish between photoautotrophs and chemoautotrophs.
3. Define photosynthesis and write the general chemical equation for photosynthesis.
4. State which organisms undergo photosynthesis.
5. Distinguish between the site of photosynthesis in prokaryotic cells and in eukaryotic cells.
6. Describe the structure of the chloroplast in eukaryotic cells and describe where in the chloroplast the photosynthetic pigments are located.
7. Distinguish between radiant energy and chemical energy and relate both to the process of photosynthesis.
8. Distinguish between the electromagnetic spectrum, the visible spectrum, and an absorption spectrum.
9. State which colors of the visible spectrum are absorbed by chlorophylls and which color is reflected.
10. State which chlorophyll is required for the process of photosynthesis and is therefore found in all photosynthetic organisms.
11. State which chlorophylls are found in all plants and which other photosynthetic pigments are commonly found in plants.
12. Distinguish between the light-dependent reactions and the light-independent reactions of photosynthesis and describe the relationship between the two sets of reactions.
13. Relating to the light-dependent reactions (light reactions) of photosynthesis in eukaryotic cells (e.g. plants):
a. State the membrane and the two fluid areas in the chloroplast where the light reactions occur.
b. State and distinguish between the two different energy-storing molecules that are produced by the light reactions of photosynthesis.
c. Describe a photosystem, state the two photosystems involved in the linear (noncyclic) photophosphorylation process, and state the reaction center chlorophylls in each photosystem.
d. Explain how light energy causes the reaction center chlorophyll in a photosystem to
release an electron to a primary electron acceptor.
e. Explain why chlorophyll a is considered the main photosynthetic pigment in plants and
chlorophyll b and other pigments are considered accessory.
f. Describe where the electron given off by photosystem I goes and where the electron
given off by photosystem II goes.
g. Relate the redox reactions of an electron transport chain to the active transport of
hydrogen ions (H+) across a membrane.
h. Relate the active transport of H+ ions across a membrane to the formation of an
electrochemical gradient.
i. Relate facilitated diffusion of H+ ions through the ATP synthase protein channel to the
making of ATP.
j. State the source of a replacement electron for the one given off by the reaction center
chlorophyll P680 and the source of a replacement electron for the one given off by the
reaction center chlorophyll P700.
14. Relating to the light-independent reactions (Calvin cycle) of photosynthesis in eukaryotic cells (e.g. plants):
a. State the site of the Calvin cycle in the chloroplast.
b. State the energy-storing molecules which were produced by the light reactions and which
are used as an energy source for the Calvin cycle.
c. Show the steps of the Calvin cycle, including the major molecules involved, and explain
why the Calvin cycle is considered a cycle.
d. State the 3-carbon product of the Calvin cycle and relate it to the production of glucose.
15. Describe the major functions of glucose in photosynthetic organisms.
16. Explain the role in photosynthesis of stomata in plant leaves.
17. Distinguish the major differences between C3, C4, and CAM plants.
| 4518725264 | Autotrophic | An organism capable of synthesizing its own food from inorganic substances, using light or chemical energy. Green plants, algae, and certain bacteria are autotrophs. |  | 0 |
| 4518725265 | Chloroplasts | absorbs sunlight and uses it to drive the synthesis of organic compounds from carbon dioxide and water. |  | 1 |
| 4518725266 | Photosynthesis | The conversion of light energy to chemical energy that is stored in glucose or other organic compounds; occurs in plants, algae, and certain prokaryotes. |  | 2 |
| 4518725267 | Heterotrophs | An organism that obtains organic food molecules by eating other organisms or substances derived from them. |  | 3 |
| 4518725268 | Stomata | pores on the leaf where O2 exits and CO2 enters |  | 4 |
| 4518725269 | Stroma | The fluid of the chloroplast surrounding the thylakoid membrane; involved in the synthesis of organic molecules from carbon dioxide and water. |  | 5 |
| 4518725270 | Thylakoids | A flattened, membranous sac inside a chloroplast. They often exist in stacks called grana that are interconnected; their membranes contain molecular "machinery" used to convert light energy to chemical energy. |  | 6 |
| 4518725271 | Chlorophyll | Green pigment located in membranes within the chloroplasts of plants and algae and in the membranes of certain prokaryotes. |  | 7 |
| 4518725272 | Light Reactions | The first of two major stages in photosynthesis (preceding the Calvin cycle). These reactions, which occur on the thylakoid membranes of the chloroplast or on membranes of certain prokaryotes, convert solar energy to the chemical energy of ATP and NADPH, releasing oxygen in the process. |  | 8 |
| 4518725273 | Calvin cycle | The second of two major stages in photosynthesis (following the light reactions), involving fixation of atmospheric CO2 and reduction of the fixed carbon into carbohydrate. |  | 9 |
| 4518725274 | Carbon Fixation | The conversion of inorganic carbon (for example, CO2) into organic forms (for example, sugars). |  | 10 |
| 4518725275 | Carotenoids | An accessory pigment, either yellow or orange, in the chloroplasts of plants and in some prokaryotes. By absorbing wavelengths of light that chlorophyll cannot, they broaden the spectrum of colors that can drive photosynthesis. |  | 11 |
| 4518725276 | C3 plants | A plant that uses the Calvin cycle for the initial steps that incorporate CO2 into organic material, forming a three-carbon compound as the first stable intermediate. |  | 12 |
| 4518725277 | Photorespiration | A series of reactions in plants in which O2 replaces CO2 during the Calvin Cycle, preventing carbon fixation; this wasteful process dominates when C3 plants are forced to close the stomata to prevent water loss |  | 13 |
| 4518725278 | C4 Plants | A plant in which the Calvin cycle is preceded by reactions that incorporate CO2 into a four-carbon compound, the end product of which supplies CO2 for the Calvin cycle. (sugar cane, corn, and members of the grass family) |  | 14 |
| 4518725279 | CAM plants | A plant that uses a metabolism adapted for photosynthesis in arid conditions. In this process, carbon dioxide entering open stomata during the night is converted to organic acids, which release CO2 for the Calvin cycle during the day, when stomata are closed. |  | 15 |
| 4518725280 | 6CO2 + 6H2O → C6H12O6 + 6O2 | What is the balanced equation for photosynthesis? |  | 16 |
| 4518725281 | H2O | What provides electrons for the light reactions? . |  | 17 |
| 4518725282 | Carbon dioxide (CO2) | What provides the carbon atoms that are incorporated into sugar molecules in the Calvin cycle? |  | 18 |
| 4518725283 | The stroma | Where does the Calvin Cycle take place?. | | 19 |
| 4518725284 | pigment | Light-absorbing molecule |  | 20 |
| 4518725285 | ATP | (Adenosine triphosphate molecule) main energy source that cells use for most of their work. |  | 21 |
| 4518725286 | ADP | (Adenosine diphosphate) The compound that remains when a phosphate group is removed from ATP. When all related reactions occur, energy is released. Can also be converted back to ATP in effect storing potential energy |  | 22 |
