Questions and Answers
Which of the following equations represents photosynthesis?
In which of the following organelles does photosynthesis take place?
Chloroplast
What connects the two photosystems in the light reactions?
An electron transport chain
What two molecules are produced by the light reactions and used to power the Calvin cycle?
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What provides electrons for the light reactions?
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What provides the carbon atoms that are incorporated into sugar molecules in the Calvin cycle?
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What transports electrons from the light reactions to the Calvin cycle?
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The light reactions take place in the _________ and the Calvin cycle takes place in the _________.
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Which of the following are photoautotrophs?
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Why would the asteroid or comet impact have had such a major impact on life on Earth?
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Which leaf type would be the most efficient at absorbing sunlight?
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Which structure allows for gas exchange between the tissues of a leaf and the atmosphere?
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Guard cells open during the day to allow gases to flow through the stomata.
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Chlorophyll is found in the __________ of chloroplasts.
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Carbon dioxide enters a leaf through the _____
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What is the source of the oxygen produced by photosynthesis?
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The light reactions produce _____
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The thylakoid membranes bring together the components necessary to carry out the _____
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Which option summarizes the inputs and outputs of the Calvin cycle?
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_____ has a longer wavelength than _____.
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What range do pigments in the granum absorb mainly?
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Which color is most strongly reflected by chlorophyll?
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Which of these phosphorylates ADP to make ATP?
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_____ releases energy that is used to pump hydrogen ions from the stroma into the thylakoid compartment.
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_____ splits water into 1/2 O2, H+, and e-.
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Energized electrons from ____ enter an electron transport chain and are then used to reduce NADP+.
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Chlorophyll can be found in _____.
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What is the final electron acceptor in the light reactions of photosynthesis?
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As photosynthesis occurs in chloroplasts, O2 is produced from _____ via a series of reactions associated with _____.
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Carbon fixation involves the addition of carbon dioxide to _____.
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After 3-PGA is phosphorylated, it receives energized electrons from _____.
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How many carbon dioxide molecules must be added to RuBP to make a single molecule of glucose?
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In the Calvin cycle, how many ATP molecules are required to regenerate RuBP from five G3P molecules?
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The radioactive isotope used in the Calvin experiments was ____.
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The Calvin cycle describes the conversion of ___.
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Paper chromatography is used to _____.
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What type of organism was used in Calvin's experiments?
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In simple summary form, the input of the Calvin cycle for every product is __________, and the output is __________ used for glucose synthesis.
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The Calvin cycle is a series of reactions that _____.
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Why do the reactions of the Calvin cycle usually not occur at night?
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Which major physical change could be attributed to photosynthesis?
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What is the likely outcome when a small green plant seedling is placed in phenol red in the dark?
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What has a large, healthy philodendron been using for an energy source while in the dark?
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What is the basis for expecting the growth of phytoplankton could help slow global warming?
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What is the main cause of the current amplification of global climate change?
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Which of the following is NOT a greenhouse gas?
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Study Notes
Photosynthesis Overview
- Photosynthesis equation: 6CO2 + 6H2O → C6H12O6 + 6O2; requires carbon dioxide and water to produce sugar and oxygen.
- Chloroplasts are the organelles that perform photosynthesis, using light energy to convert CO2 and H2O into glucose and oxygen.
Light Reactions
- Photosystems are connected by an electron transport chain, facilitating the movement of electrons during light reactions.
- Key products of the light reactions: ATP and NADPH, utilized in the Calvin cycle.
- Water (H2O) donates electrons when split, releasing oxygen as a byproduct.
- Light reactions occur in thylakoids; the Calvin cycle occurs in the stroma of chloroplasts.
- NADPH carries electrons from light reactions to the Calvin cycle.
Calvin Cycle
- Carbon dioxide provides carbon atoms used in sugar formation; the process begins with CO2 and RuBP.
- Current outputs of the cycle include G3P (a three-carbon molecule), which can be synthesized into glucose.
- Six CO2 molecules must be added to RuBP to generate one glucose molecule.
- The cycle necessitates ATP and NADPH derived from light reactions for energy and reducing power.
Environmental Impact of Photosynthesis
- Large asteroid impacts may have led to mass extinctions by blocking sunlight, halting photosynthesis and life.
- Green leaves with large surface areas absorb sunlight efficiently; chlorophyll reflects green light, making leaves appear green.
- Gas exchange occurs through stomata, regulated by guard cells that open during the day.
Experimental Techniques and Historical Context
- Calvin experiments utilized algae and carbon-14 isotopes to trace photosynthetic pathways.
- Paper chromatography separates components, helping identify pigments involved in photosynthesis.
- Evidence highlights that photosynthesis started over three billion years ago, significantly increasing atmospheric oxygen.
Important Reactions and Mechanisms
- Oxygen produced during photosynthesis comes from water splitting, not from CO2.
- Photosystem II is responsible for splitting water into O2, protons, and electrons.
- ATP synthase phosphorylates ADP to produce ATP during light reactions.
Current Issues and Global Climate Change
- Human activity amplifies climate change through increased greenhouse gas concentrations, resulting in rising temperatures, polar ice melt, and extreme weather events.
- Enhancing phytoplankton growth by adding iron to ocean environments may capture atmospheric CO2, acting as a carbon sink.
- Plants store surplus energy as starch, which they use during periods without light, like during prolonged darkness.
Summary of Key Processes
- The light reactions yield oxygen, NADPH, and ATP, while the Calvin cycle converts carbon dioxide into carbohydrates.
- Both metabolic pathways are critically interdependent, ensuring energy transfer and matter cycling within ecosystems.
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Description
Explore the intricate processes of photosynthesis, including the light reactions and the Calvin cycle. This quiz covers key concepts such as the photosynthesis equation, the role of chloroplasts, and the transformation of light energy into chemical energy. Test your knowledge of how plants convert carbon dioxide and water into glucose and oxygen.
