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18 Cards in this Set

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In most land plants, photosynthesis occurs in cells of the __________ of the leaves, because these cells contain the largest numbers of chloroplasts.
mesophyll
Light energy is initially captured by "photosystems" within thylakoid membranes. Photosystems are organized arrays of
chlorophyll molecules,
proteins,
pigment molecules such as carotenoids
Why is carbon dioxide a key molecule in the light-independent reactions of photosynthesis?
Carbon dioxide, together with water, is the raw material for the synthesis of sugars, which are the key products of the light-independent reactions.
What is photorespiration?
the process that prevents sugar production in C3 plants when CO2 levels are low and O2 levels are high.
In the light-dependent reactions of photosynthesis, ATP is produced by chemiosmosis. Describe this process.
As high-energy electrons move from carrier to carrier in the electron transport system of the thylakoid membrane, some of the energy is captured to pump hydrogen ions across it.
A lovely tree called the flowering plum has beautiful pink flowers in spring and deep-purple leaves in summer. What types of pigments are plentiful in this plant? Can photosynthesis occur in these purple leaves? Explain your answer.
The leaves probably contain a high amount of phycocyanins and carotenoids and less chlorophyll than do plants with green leaves. They can still perform photosynthesis, because photosynthesis can occur to some extent at all wavelengths of light.
Take a deep breath and slowly exhale. The oxygen in that breath is being used by your mitochondria in reactions that produce ATP from sugars and other food molecules you ate. Where did that oxygen come from originally?
The oxygen in the air is produced by the splitting of water during the light-dependent reactions of photosynthesis
A scientist studying photosynthesis illuminated a culture of algae with bright visible light. She then turned out the light and simultaneously began to bubble radioactive CO2 gas into the culture. After 30 minutes, she stopped the reaction and measured the amount of radioactivity inside the cells. What did she find? Explain your answer.
There was radioactivity in the cells, because the CO2 is used to synthesize sugar, even in the dark.
During photosynthesis, electrons are continuously lost from the reaction center of photosystem II. What source is used to replace these electrons?
water
The term carbon fixation refers to __________.
the incorporation of atmospheric carbon dioxide into a larger organic molecule
You have just discovered a new plant with red-orange leaves. What wavelengths of visible light are NOT being absorbed by this pigment?
red and orange
In the light-dependent reactions of photosynthesis the difference in hydrogen ion concentration across the thylakoid membrane is used to generate __________.
ATP
____________________ converts the energy of sunlight into chemical energy
Photosynthesis
____________________ are organisms that can produce their own food in their cells
Autotrophs
Photosynthesis takes place within ____________________.
Choroplasts
Where do the light-independent, carbon-fixing reactions occur?
In the chloroplast stroma
The role of accessory pigments is to
capture additional light energy and transfer it to the chlorophyll reaction centers
Where do the light-dependent reactions of photosynthesis occur?
within the thylakoid membranes of the chloroplast