Answers To Photosynthesis Practice
Answers to Photosynthesis Practice
AP Biology
1. Draw a picture of the chloroplast and label the stroma, thylakoid, thylakoid lumen (space), inner membrane, outer membrane. 2. Using 18O as the basis of your discussion, explain how we know that the oxygen released in photosynthesis comes from water. When the oxygen in water has the radioactively labeled oxygen, the gas released from photosynthesis also has the labeled oxygen. This shows that the oxygen gas given off during photosynthesis comes from the splitting of water molecules. (If the oxygen in carbon dioxide is labeled instead, the tracer shows that it is incorporated into sugar and water.)
3. Label the figure below. As you work, underline or highlight the items that are cycled between the light reactions and
Calvin cycle.
4. Explain the correlation between an absorption spectrum and an action spectrum.
An absorption spectrum describes the ability of a pigment to absorb each wavelength of light, while an action spectrum shows the effectiveness of each wavelength to drive a process. (The two should correlate since the ability to drive a process depends on the absorption of energy.)
5. Describe how Engelmann was able to form an action spectrum long before the invention of a spectrophotometer.
Engelmann used a filament of photosynthetic algae, exposed to different wavelengths of light, to show that aerobic bacteria would grow best in the presence of wavelengths that were absorbed. (Growth of bacteria showed that oxygen was being released, which showed that photosynthesis was occurring. The green wavelength showed the least amount of photosynthesis/oxygen since green light is reflected by chlorophyll and not absorbed.)
6. A photosystem is composed of a protein complex called a reaction center complex surrounding by several light-harvesting complexes.
7. Photosystem II has a special pair of chlorophyll a molecules called P680 at its reaction center. What is the explanation for this name?
This chlorophyll
AP Biology
1. Draw a picture of the chloroplast and label the stroma, thylakoid, thylakoid lumen (space), inner membrane, outer membrane. 2. Using 18O as the basis of your discussion, explain how we know that the oxygen released in photosynthesis comes from water. When the oxygen in water has the radioactively labeled oxygen, the gas released from photosynthesis also has the labeled oxygen. This shows that the oxygen gas given off during photosynthesis comes from the splitting of water molecules. (If the oxygen in carbon dioxide is labeled instead, the tracer shows that it is incorporated into sugar and water.)
3. Label the figure below. As you work, underline or highlight the items that are cycled between the light reactions and
Calvin cycle.
4. Explain the correlation between an absorption spectrum and an action spectrum.
An absorption spectrum describes the ability of a pigment to absorb each wavelength of light, while an action spectrum shows the effectiveness of each wavelength to drive a process. (The two should correlate since the ability to drive a process depends on the absorption of energy.)
5. Describe how Engelmann was able to form an action spectrum long before the invention of a spectrophotometer.
Engelmann used a filament of photosynthetic algae, exposed to different wavelengths of light, to show that aerobic bacteria would grow best in the presence of wavelengths that were absorbed. (Growth of bacteria showed that oxygen was being released, which showed that photosynthesis was occurring. The green wavelength showed the least amount of photosynthesis/oxygen since green light is reflected by chlorophyll and not absorbed.)
6. A photosystem is composed of a protein complex called a reaction center complex surrounding by several light-harvesting complexes.
7. Photosystem II has a special pair of chlorophyll a molecules called P680 at its reaction center. What is the explanation for this name?
This chlorophyll