Photosynthesis Applications and Implications 2 — Questions and Answers
Question 1: Which agricultural practice directly exploits the relationship between photosynthesis and plant density?
- Crop rotation
- Plant spacing optimization (Correct answer)
- Soil pH adjustment
- Irrigation scheduling
Correct answer: Plant spacing optimization
Plant spacing is optimized so each plant receives sufficient light for maximum photosynthesis without shading competitors.
Question 2: What is the primary reason biofuels derived from algae are considered more efficient than corn-based ethanol?
- Algae require no water
- Algae have higher photosynthetic efficiency and faster growth rates (Correct answer)
- Algae do not require sunlight
- Algae produce oxygen as a byproduct
Correct answer: Algae have higher photosynthetic efficiency and faster growth rates
Algae convert solar energy to biomass far more efficiently than corn and can be harvested much more frequently.
Question 3: How does supplemental CO2 enrichment in commercial greenhouses improve crop yield?
- It raises temperature to accelerate growth
- It directly increases the rate of the Calvin cycle (Correct answer)
- It prevents photorespiration entirely
- It replaces the need for fertilizers
Correct answer: It directly increases the rate of the Calvin cycle
Elevated CO2 increases substrate availability for RuBisCO, accelerating carbon fixation in the Calvin cycle.
Question 4: Artificial photosynthesis research primarily aims to produce which commercially valuable output?
- Starch
- Hydrogen fuel (Correct answer)
- Cellulose
- Oxygen gas for medical use
Correct answer: Hydrogen fuel
Most artificial photosynthesis systems are designed to split water and generate hydrogen gas as a clean fuel source.
Question 5: A farmer notices crops grown under red-filtered plastic tunnels grow faster than those in white tunnels. What best explains this?
- Red light reduces photorespiration
- Chlorophyll absorbs red light most efficiently for photosynthesis (Correct answer)
- Red tunnels retain more heat
- Red light increases stomatal opening
Correct answer: Chlorophyll absorbs red light most efficiently for photosynthesis
Chlorophyll a and b have absorption peaks in the red wavelength range, making red light particularly effective for driving photosynthesis.
Question 6: Which environmental implication follows directly from widespread deforestation reducing global photosynthesis rates?
- Decreased soil erosion
- Increased atmospheric CO2 and reduced oxygen production (Correct answer)
- Lower ocean salinity
- Reduced evapotranspiration benefiting dryland crops
Correct answer: Increased atmospheric CO2 and reduced oxygen production
Fewer photosynthesizing trees means less CO2 is fixed and less O2 is released, contributing to climate change.
Question 7: In precision agriculture, NDVI (Normalized Difference Vegetation Index) satellite data is used to assess crop health by measuring what photosynthesis-related property?
- Soil moisture content
- Chlorophyll-driven reflectance differences between red and near-infrared light (Correct answer)
- Root biomass depth
- Stomatal density per leaf area
Correct answer: Chlorophyll-driven reflectance differences between red and near-infrared light
Healthy, photosynthetically active plants absorb red light and reflect near-infrared, creating a measurable spectral signature.
Photosynthesis Applications and Implications 2
Which agricultural practice directly exploits the relationship between photosynthesis and plant density?