What is meant by the term net exchange?
Reveal answer
Overall movement after all simultaneous processes are considered.
Key words: net exchange
2(g) GAS EXCHANGE · RECALL
2.41B Gas exchange, respiration and photosynthesis
15 recall questions · Biology only (B): not in Science (Double Award). Answer from memory, reveal the answer, then rate yourself. Ratings stay on this device.
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What is meant by the term gross photosynthesis?
Reveal answer
Total photosynthetic rate before respiratory gas exchange is subtracted.
Key words: gross photosynthesis
What is meant by the term compensation point?
Reveal answer
Light intensity where photosynthetic and respiratory gas effects balance.
Key words: compensation point
What is meant by the term photosynthetic tissue?
Reveal answer
Tissue containing functional chloroplasts and receiving suitable light.
Key words: photosynthetic tissue
Process and net gas directions: for Photosynthesis alone, give the co₂ effect and the o₂ effect.
Reveal answer
CO₂ effect: Consumed. O₂ effect: Produced.
Key words: Photosynthesis alone
Process and net gas directions: for Aerobic respiration alone, give the co₂ effect and the o₂ effect.
Reveal answer
CO₂ effect: Produced. O₂ effect: Consumed.
Key words: Aerobic respiration alone
Process and net gas directions: for Bright light; photosynthesis faster, give the co₂ effect and the o₂ effect.
Reveal answer
CO₂ effect: Net uptake. O₂ effect: Net release.
Key words: Bright light; photosynthesis faster
Process and net gas directions: for Darkness, give the co₂ effect and the o₂ effect.
Reveal answer
CO₂ effect: Net release. O₂ effect: Net uptake.
Key words: Darkness
Process and net gas directions: for Compensation point, give the co₂ effect and the o₂ effect.
Reveal answer
CO₂ effect: No net exchange. O₂ effect: No net exchange.
Key words: Compensation point
True or false, and why? “Plants take in carbon dioxide and never oxygen.”
Reveal answer
False. Plant cells use oxygen in aerobic respiration.
True or false, and why? “Respiration stops when photosynthesis begins.”
Reveal answer
False. Respiration continues in light and dark.
True or false, and why? “No net gas exchange means the leaf is inactive.”
Reveal answer
False. Photosynthesis and respiration may be active at equal rates.
Which process in a plant uses oxygen and releases carbon dioxide all the time?
Reveal answer
Aerobic respiration.
Key words: respiration
Which process in a plant uses carbon dioxide and releases oxygen, but only in the light?
Reveal answer
Photosynthesis.
Key words: photosynthesis
Why does the net gas exchange of a leaf change during the day?
Reveal answer
Light intensity changes → rate of photosynthesis changes while respiration stays roughly steady → the balance between them shifts.
Key words: balance