Gaokao Biology: Cell Biology and Metabolism Flashcards

The net equation for glycolysis converting one glucose molecule is BEST represented as:

Answer: C₆H₁₂O₆ → 2C₃H₄O₃ + 4H + 2 ATP (net)

Glycolysis produces 2 pyruvate (C₃H₄O₃), 2 net ATP, 2 NADH, and 2 water molecules from one glucose in the cytoplasm without oxygen.

Cholesterol molecules in the cell membrane serve to:

Answer: Regulate membrane fluidity at varying temperatures

Cholesterol intercalates between phospholipids; at high temperatures it restricts movement (decreasing fluidity), while at low temperatures it prevents packing (maintaining fluidity).

In the electron transport chain, the final electron acceptor is:

Answer: Molecular oxygen (O₂)

Oxygen is the terminal electron acceptor in aerobic respiration; it accepts electrons and combines with H⁺ to form water at Complex IV.

Which cell structure is responsible for modifying, sorting, and packaging proteins for secretion?

Answer: Golgi apparatus

The Golgi apparatus receives proteins from the ER in vesicles, modifies them (e.g., glycosylation), sorts them, and packages them into secretory vesicles.

When a plant cell is placed in a hypertonic solution, what occurs?

Answer: Plasmolysis occurs as water leaves the cell by osmosis

In a hypertonic solution, water moves out of the cell by osmosis, causing the vacuole to shrink and the plasma membrane to pull away from the cell wall (plasmolysis).

ATP synthase in the mitochondria produces ATP using energy derived from:

Answer: The proton gradient across the inner mitochondrial membrane

H⁺ ions flow down their electrochemical gradient through ATP synthase (Complex V) from the intermembrane space to the matrix, driving ATP synthesis via chemiosmosis.

Which type of cell division produces four haploid daughter cells genetically different from the parent cell?

Answer: Meiosis

Meiosis undergoes two rounds of division (meiosis I and II) after one round of DNA replication, producing four genetically unique haploid cells (gametes or spores).