Gaokao Biology: Cell Biology and Metabolism Flashcards
7 cards from real GAOKAO practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Gaokao Biology: Cell Biology and Metabolism flashcards as text
A cell biologist treats cells with colchicine, which disrupts microtubule polymerization. Which process would be MOST directly affected?
Answer: Chromosome separation during mitosis
Colchicine prevents spindle fiber formation by binding to tubulin, arresting cells in metaphase and preventing chromosome movement to the poles.
The 'induced fit' model of enzyme action states that:
Answer: The active site changes shape to fit the substrate upon binding
In the induced fit model, substrate binding causes the enzyme's active site to change shape, forming a more complementary fit that stabilizes the transition state.
Which molecule serves as the direct energy currency of the cell?
Answer: ATP
ATP (adenosine triphosphate) is the universal energy currency; its hydrolysis releases free energy that drives endergonic reactions throughout the cell.
During the S phase of the cell cycle, which protein complex recruits DNA polymerase to origins of replication?
Answer: Origin recognition complex (ORC)
The origin recognition complex (ORC) binds to origins of replication and serves as a landing pad for licensing factors and replication machinery including helicase and DNA polymerase.
In aerobic respiration, FADH₂ donates electrons to the electron transport chain at Complex:
Answer: II
FADH₂ donates electrons directly to Complex II (succinate dehydrogenase), bypassing Complex I, which is why FADH₂ yields fewer ATP molecules than NADH.
The Z-scheme of photosynthesis describes:
Answer: The sequential flow of electrons from water through PSII and PSI to NADP⁺
The Z-scheme shows the non-cyclic electron flow: H₂O → PSII → plastoquinone → cytochrome b6f → plastocyanin → PSI → ferredoxin → NADP⁺, the overall path resembling a 'Z' when plotted against redox potential.
A mutation that disrupts the signal peptide of a secretory protein would most likely cause the protein to:
Answer: Remain in the cytoplasm instead of entering the ER
Signal peptides direct ribosomes to the rough ER; without a functional signal peptide, the ribosome translates the protein in the cytoplasm rather than threading it into the ER lumen.