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The rate of photosynthesis increases in the leaf exposed to higher light intensities.
Given:
The graphs representing the rate of photosynthesis as a function of the intensity of light.
Introduction:
The process of photosynthesis is light dependent. Photosynthesis converts light energy into chemical energy. The rate of photosynthesis will increase if the leaves are exposed to the higher intensity of light.
Explanation of Solution
Photosynthesis is a light-dependent process. This process uses light energy to produce carbohydrate and provide energy to plant for various
The rate of photosynthesis increases when there are higher light intensities. The leaves, which are exposed to the higher intensity of light, show high rate of photosynthesis. At low light intensity, the leaves will show a decrease in the rate of photosynthesis. The leaves with the larger surface area and high density of chlorophyll will show a high rate of photosynthesis as they can absorb more light.
From the given graphs, it is clearly visible that both the plants show increasing rate of photosynthesis in high intensity of light (shown by orange line) and rate of photosynthesis is low in low intensity of light (shown by purple line). The photosynthesis is directly proportional to the intensity of light, so the curves of photosynthesis increase with increasing light intensities.
This occurs because of the increase in the rate of light-dependent reactions, which in turn results in the increase in photosynthesis rate. However, the rate of photosynthesis is dependent on other factors like temperature and carbon dioxide concentration. Therefore, with further increase in light intensity, the photosynthesis rate does not rise further and eventually plateaus.
Thus, it can be concluded that photosynthesis is a light-dependent process. The rate of photosynthesis is directly proportional to the intensity of the light but to a certain extent only, as photosynthesis is controlled by various other factors also.
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Chapter 10 Solutions
Life: The Science of Biology
- Where in plant cells does the Calvin cycle take place? a. thylakoid membrane b. thylakoid space c. stroma d. granumarrow_forwardMelvin Calvin and Andrew Benson determined the steps in the light-independent reactions of photosynthesis by exposing the green alga Chlorella to CO2 labeled with the radioisotope carbon 14. By looking at which compounds the C14 ended up in, they were able to identify all intermediates in this cyclic pathway. Why did they predict correctly that the same set of intermediates would be formed in the light reaction in land plants?arrow_forwardPfr, the active state of _______________, forms when red light is absorbed. (a) photosystem I (b) phytochrome (c) far-red light (d) phototropin (e) cryptochromearrow_forward
- Which part of the Calvin cycle would be affected if a cell could not produce the enzyme RuBIsCO?arrow_forwardPhotosynthesis directly opposes respiration in determining how plants influence atmospheric CO2 concentrations. When a leaf is in the light, both photosynthesis and respiration are occurring simultaneously. The data in the Table were collected from the leaf of a sagebrush plant that was enclosed in a chamber that measures the rate of CO2 exchange. The same leaf was used to collect the data in Interpret the Data in Chapter 7. Respiration is shown as a negative and photosynthesis as a positive rate of CO2 exchange. The net photosynthesis rate is the amount of CO2 (in micromoles per square meter per second) assimilated by the leaf while respiration is occurring; a positive value indicates more photosynthesis is occurring than respiration. The light exposed to the leaf is quantified as the number of photons in the 400 to 700 nm wavelength, the photosynthetic photon flux density (PPFD); 2,000 mol/m2/s is equivalent to the amount of light occurring at midday in full Sun. Observation Photosynthetic Photon Flux Density (PPFD) (mol/m2/s) Net Photosynthesis (mol/m2/s) 1 2,000 9.1 2 1,500 8.4 3 1,250 8.2 4 1,000 7.4 5 750 6.3 6 500 4.8 7 250 2.2 8 0 -2.0 Why is net photosynthesis negative when PPFD is zero? Looking at the respiration data from Interpret the Data in Chapter 7, at what temperature do you think these data were collected? Source: Data based on unpublished research by Brent Ewers, University of Wyoming.arrow_forwardThe distinctly blue shade of a blue spruce results from the scattering of light by small waxy particles that coat the leaves. Explain how this scattering can protect the leaves from damage by short-wavelength ultraviolet light while still permitting the passage of longer wavelengths of light for photosynthesis.arrow_forward
- Why would low humidity reduce the efficiency of photosynthesis?arrow_forwardWhat are the products of the light-dependent reactions of photosynthesis? Select all that apply. NADPH O2gas ATP Sugarsarrow_forwardWhat is the name of the cellular structure where the light-dependent reactions of photosynthesis occur in plants? Stroma Thylakoid membrane Outer chloroplast membrane Stomataarrow_forward
- The light dependent reactions of photosynthesis serve to __________ while the light independent reactions serve to ______ .arrow_forwardWhat would be the effect on plants if photorespiration did not exist?arrow_forwardWhat purpose does the thylakoid space serve during the light reactions of photosynthesis?arrow_forward
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