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Questions and Answers
Which chlorophyll pigment is primarily responsible for the direct conversion of light energy to chemical energy?
Which chlorophyll pigment is primarily responsible for the direct conversion of light energy to chemical energy?
- Accessory pigments
- Chlorophyll b
- Carotenoids
- Chlorophyll a (correct)
Chlorophyll b has an absorption spectrum shifted toward violet wavelengths.
Chlorophyll b has an absorption spectrum shifted toward violet wavelengths.
False (B)
What is the structure at the center of the porphyrin ring in chlorophyll?
What is the structure at the center of the porphyrin ring in chlorophyll?
magnesium atom
Chlorophyll b complements chlorophyll a by increasing the proportion of _____ in sunlight that plants can harvest.
Chlorophyll b complements chlorophyll a by increasing the proportion of _____ in sunlight that plants can harvest.
What happens to the electrons in the porphyrin ring when photons are absorbed?
What happens to the electrons in the porphyrin ring when photons are absorbed?
Carotenoids are highly efficient in transferring energy absorbed from photons.
Carotenoids are highly efficient in transferring energy absorbed from photons.
Match the chlorophyll pigment with its characteristic:
Match the chlorophyll pigment with its characteristic:
The process by which chlorophyll absorbs photons is analogous to the _____ effect.
The process by which chlorophyll absorbs photons is analogous to the _____ effect.
What role does chlorophyll play in photosynthesis?
What role does chlorophyll play in photosynthesis?
Jospeh Priestly discovered that plants do not contribute anything to the air.
Jospeh Priestly discovered that plants do not contribute anything to the air.
What two compounds are produced during the light-dependent reactions of photosynthesis?
What two compounds are produced during the light-dependent reactions of photosynthesis?
Jan Baptista van Helmont incorrectly concluded that the water mainly accounted for the plant's increased ______.
Jan Baptista van Helmont incorrectly concluded that the water mainly accounted for the plant's increased ______.
Match the scientists with their contributions to the understanding of photosynthesis:
Match the scientists with their contributions to the understanding of photosynthesis:
What does the photosystem primarily act as in photosynthesis?
What does the photosystem primarily act as in photosynthesis?
Light-independent reactions are also known as the Calvin cycle.
Light-independent reactions are also known as the Calvin cycle.
What did Priestly's experiment with mint and a candle demonstrate?
What did Priestly's experiment with mint and a candle demonstrate?
What is the role of NADP+ in the light-dependent reactions of photosynthesis?
What is the role of NADP+ in the light-dependent reactions of photosynthesis?
Chloroplasts are responsible for photosynthesis in all plants.
Chloroplasts are responsible for photosynthesis in all plants.
What do the light-dependent reactions produce that is essential for synthesizing sugars?
What do the light-dependent reactions produce that is essential for synthesizing sugars?
Pigments absorb light energy in the __________ range to facilitate photosynthesis.
Pigments absorb light energy in the __________ range to facilitate photosynthesis.
Match the following terms with their correct descriptions:
Match the following terms with their correct descriptions:
Which of the following statements about the electromagnetic spectrum is correct?
Which of the following statements about the electromagnetic spectrum is correct?
Chlorophyll is responsible for reflecting green light, which is why chlorophyll-rich plants appear green.
Chlorophyll is responsible for reflecting green light, which is why chlorophyll-rich plants appear green.
What factors affect the strength of the photoelectric effect?
What factors affect the strength of the photoelectric effect?
Explain why shorter wavelengths of light contain higher energy photons.
Explain why shorter wavelengths of light contain higher energy photons.
Longer wavelengths of light are generally more effective at producing the photoelectric effect than shorter wavelengths.
Longer wavelengths of light are generally more effective at producing the photoelectric effect than shorter wavelengths.
What is the phenomenon called when photons transfer energy to electrons?
What is the phenomenon called when photons transfer energy to electrons?
Each pigment has a characteristic __________ spectrum.
Each pigment has a characteristic __________ spectrum.
Match the following types of chlorophyll with their preferred light absorption:
Match the following types of chlorophyll with their preferred light absorption:
Which types of pigments are primarily used in green plant photosynthesis?
Which types of pigments are primarily used in green plant photosynthesis?
Chloroplasts act as photoelectric devices by absorbing sunlight and transferring excited electrons to a carrier.
Chloroplasts act as photoelectric devices by absorbing sunlight and transferring excited electrons to a carrier.
When a photon strikes a molecule with sufficient energy, it raises an electron to a higher __________ level.
When a photon strikes a molecule with sufficient energy, it raises an electron to a higher __________ level.
What is the main role of carotenoids in photosynthesis?
What is the main role of carotenoids in photosynthesis?
Phycobiliproteins are accessory pigments found only in plants.
Phycobiliproteins are accessory pigments found only in plants.
What happens when photosynthetic saturation is reached?
What happens when photosynthetic saturation is reached?
A generalized photosystem contains an antenna complex and a ________ center.
A generalized photosystem contains an antenna complex and a ________ center.
Match the following components of photosystems with their respective functions:
Match the following components of photosystems with their respective functions:
Which statement best describes the function of the reaction center in a photosystem?
Which statement best describes the function of the reaction center in a photosystem?
Chlorophyll molecules operate independently in absorbing light for photosynthesis.
Chlorophyll molecules operate independently in absorbing light for photosynthesis.
Carotenoids and accessory pigments are important for survival in ________ light situations.
Carotenoids and accessory pigments are important for survival in ________ light situations.
Study Notes
Photosynthetic Pigments
- Chlorophyll a is the main photosynthetic pigment in plants and cyanobacteria.
- Chlorophyll b acts as an accessory pigment and complements chlorophyll a by expanding its light absorption range.
- Chlorophylls contain a porphyrin ring containing a central magnesium atom.
- Pigments absorb photons by transferring energy to electrons, similar to the photoelectric effect.
- Variations in side groups and associations with proteins alter the absorption properties of different types of chlorophylls.
- Carotenoids are pigments that absorb photons across a wide range of energies, efficiently transferring the energy to a key chlorophyll molecule in contact with a protein.
- Phycobiliproteins are accessory pigments found in cyanobacteria and some algae.
- These pigments are crucial for survival in low-light conditions in oceans.
Photosystem Organization
- Photosystems are clusters of chlorophyll and accessory pigment molecules that absorb light energy.
- Photosystems channel excitation energy gathered by multiple pigment molecules to a single reaction center chlorophyll molecule.
- The reaction center chlorophyll molecule then passes the energy out of the photosystem as excited electrons, driving the synthesis of ATP and organic molecules.
- Photosystems consist of an antenna complex and a reaction center.
- The antenna complex collects light energy and transfers it to the reaction center.
- The reaction center converts light energy into chemical energy by transferring excited electrons to molecules involved in ATP and NADPH production.
Light-Dependent Reactions
- Light energy is used to reduce NADP+ and synthesize ATP, which are then used to reduce carbon dioxide and form organic molecules.
- The electrons released from water molecules are transferred to NADP+ during the light-dependent reactions.
Light-Independent Reactions
- ATP and NADPH produced in the light-dependent reactions are used to reduce carbon dioxide into sugars in the light-independent reactions.
- The process occurs within chloroplasts and is crucial for plant growth and carbon fixation.
Discovery of Photosynthetic Processes
- Jan Baptista van Helmont performed an experiment to test the source of plant growth incorrectly concluding that it was water.
- Joseph Priestly discovered that plants add something to the air by observing that mint revived air unsuitable for burning a candle.
- Jan Ingenhousz found that plants only release oxygen in the presence of light.
- These experiments show that photosynthesis occurs within chloroplasts and that the light-dependent reactions are essential for the production of ATP and NADPH, which are then used in light-independent reactions to reduce carbon dioxide.
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Description
This quiz covers the essential pigments involved in photosynthesis, including chlorophyll a, b, carotenoids, and phycobiliproteins. Understand their roles and absorption properties in different light conditions. Test your knowledge on the organization of photosystems in plants and cyanobacteria.
