Which of the following is a hydrophobic protein complex involved in photosynthesis?

The correct answer is B: Photosystem I (PSI) in thylakoid membrane. Photosystem I is an integral membrane protein complex with multiple transmembrane domains, making it hydrophobic. Rubisco is soluble, while ferredoxin and plastocyanin are soluble electron carriers. This biochemical distinction is important for understanding photosynthetic mechanisms.

In the light-dependent reactions, where exactly does the photolysis of water occur?

The correct answer is B: Thylakoid membrane (lumen side). Water photolysis occurs in the thylakoid lumen as part of Photosystem II, releasing O2, H+, and electrons that drive the electron transport chain.

What is the hybridization state of the central carbon atom in the carbonate ion (CO₃²⁻)?

The correct answer is B: sp². In the carbonate ion CO₃²⁻, the central carbon atom forms three sigma bonds with oxygen atoms and is involved in resonance structures with delocalized pi electrons. This trigonal planar geometry requires sp² hybridization, with three hybrid orbitals arranged at 120° angles and one unhybridized p orb

Which of the following statements about stomatal opening is correct?

The correct answer is B: Potassium ions accumulate in guard cells during stomatal opening. During stomatal opening, potassium ions (K+) actively accumulate in guard cells, increasing osmotic potential and causing water influx.