BioInteractive Outputs and Ecological Roles of Photosynthesis 2 — Questions and Answers
Question 1: How is glucose produced in photosynthesis used by the plant itself?
- For cellular respiration, growth, structural materials (cellulose), and storage (starch) (Correct answer)
- Only for cellular respiration
- Exclusively exported to animals
- Stored only as sucrose and never broken down
Correct answer: For cellular respiration, growth, structural materials (cellulose), and storage (starch)
Plants use photosynthetically produced glucose for energy (respiration), building cell walls (cellulose), storing energy (starch), and synthesizing other organic molecules.
Question 2: What is the connection between photosynthesis and fossil fuels?
- Fossil fuels are ancient organic carbon originally fixed by photosynthesis millions of years ago (Correct answer)
- Fossil fuels are formed from inorganic minerals unrelated to photosynthesis
- Photosynthesis produces fossil fuels directly
- Fossil fuels release energy that was generated by animal metabolism
Correct answer: Fossil fuels are ancient organic carbon originally fixed by photosynthesis millions of years ago
Coal, oil, and natural gas are the remains of ancient photosynthetic organisms; combusting them releases CO2 that was fixed from the atmosphere millions of years ago.
Question 3: Which ecosystem type has the highest net primary productivity on Earth?
- Tropical rainforests (Correct answer)
- Temperate grasslands
- Arctic tundra
- Open ocean (pelagic zone)
Correct answer: Tropical rainforests
Tropical rainforests have the highest NPP due to year-round warmth, high rainfall, and intense solar radiation that support continuous, rapid photosynthesis.
Question 4: How do algae and cyanobacteria contribute to global photosynthesis?
- They account for roughly half of all photosynthesis on Earth, primarily in oceans and freshwater (Correct answer)
- They perform less than 1% of global photosynthesis
- They only photosynthesize in hot springs
- They use a different mechanism that doesn't produce O2
Correct answer: They account for roughly half of all photosynthesis on Earth, primarily in oceans and freshwater
Phytoplankton (algae and cyanobacteria) in aquatic environments contribute approximately 50% of global primary production and most of the oxygen in Earth's atmosphere.
Question 5: What is the relationship between photosynthesis and the nitrogen cycle?
- Photosynthesis requires nitrogen for chlorophyll and enzymes; plants absorb inorganic nitrogen and incorporate it into organic molecules using carbon skeletons from photosynthesis (Correct answer)
- Photosynthesis converts N2 directly into protein
- Nitrogen is produced as a byproduct of the light reactions
- Photosynthesis and the nitrogen cycle are completely independent
Correct answer: Photosynthesis requires nitrogen for chlorophyll and enzymes; plants absorb inorganic nitrogen and incorporate it into organic molecules using carbon skeletons from photosynthesis
Carbon skeletons (e.g., organic acids) produced in photosynthesis are combined with absorbed nitrogen to synthesize amino acids, nucleotides, and chlorophyll itself.
Question 6: How does photosynthesis affect local and global climate?
- Through evapotranspiration (cooling), CO2 uptake (reducing greenhouse effect), and albedo effects of vegetation cover (Correct answer)
- Photosynthesis has no measurable effect on climate
- Photosynthesis warms the environment by releasing heat
- Photosynthesis only affects climate in tropical regions
Correct answer: Through evapotranspiration (cooling), CO2 uptake (reducing greenhouse effect), and albedo effects of vegetation cover
Forests and other vegetation cool local climates through transpiration, reduce global warming by sequestering CO2, and alter Earth's reflectivity (albedo) compared to bare ground.
BioInteractive Outputs and Ecological Roles of Photosynthesis 2
How is glucose produced in photosynthesis used by the plant itself?