When O2 concentration is high, RuBisCO catalyzes oxygenase activity, causing O2 to react with RuBP instead of CO2, initiating photorespiration.

Stomata open during the day (when light is available for photosynthesis) and close at night. This reduces water loss during low photosynthetic activity periods.

Water photolysis occurs in the thylakoid lumen as part of Photosystem II, releasing O2, H+, and electrons that drive the electron transport chain.

Sugarcane is a C4 plant adapted to high light and temperature conditions. C4 plants first fix CO2 into a 4-carbon compound (oxaloacetate).

Exudation or guttation occurs when root pressure forces water out through specialized pores (hydathodes) as liquid water droplets, typically observed in early morning.

Abscisic acid (ABA) promotes seed dormancy and inhibits germination, acting antagonistically to gibberellins which promote germination.

For every 3 turns of Calvin cycle (fixing 3 CO2), 9 ATP and 6 NADPH are used. This gives a ratio of 3:2 (ATP:NADPH).

Osmosis is passive transport of water molecules across a semipermeable membrane in response to water potential differences.

The Casparian strip contains suberin (waxy substance) and lignin, which prevents apoplastic (cell wall) movement of water and minerals, forcing symplastic transport.

The nucleolus within the nucleus is the site of ribosomal RNA (rRNA) synthesis and ribosome assembly in eukaryotic cells.