Gaokao Biology: Cell Biology and Metabolism Flashcards

The process by which cells engulf large particles or other cells by membrane folding is called:

Answer: Phagocytosis

Phagocytosis ('cell eating') involves pseudopods engulfing large particles into a phagosome, which then fuses with lysosomes for digestion.

Which molecule carries amino acids to the ribosome during translation?

Answer: tRNA

Transfer RNA (tRNA) molecules have anticodons that recognize mRNA codons and carry the corresponding amino acid to the ribosome.

Photosystem I (PSI) primarily absorbs light at a peak wavelength of 700 nm and its main function is to:

Answer: Reduce NADP⁺ to NADPH

PSI uses light energy to transfer electrons to ferredoxin, which ultimately reduces NADP⁺ to NADPH for use in the Calvin cycle.

Which of the following is a characteristic feature distinguishing prokaryotic cells from eukaryotic cells?

Answer: Absence of membrane-bound nucleus

Prokaryotic cells lack a membrane-bound nucleus; their genetic material exists as a nucleoid region in the cytoplasm.

The Km (Michaelis constant) of an enzyme is BEST described as:

Answer: The substrate concentration at which reaction rate is half of Vmax

Km represents the substrate concentration at which the reaction velocity is half of Vmax and is an indicator of the enzyme's affinity for its substrate.

During interphase, DNA replication occurs in which sub-phase?

Answer: S phase

DNA replication occurs during the S (synthesis) phase of interphase, doubling the cell's genetic material in preparation for cell division.

Which product of anaerobic respiration in yeast is commercially important in baking?

Answer: Carbon dioxide

Yeast fermentation produces CO₂ gas that causes bread dough to rise; ethanol is the other product but evaporates during baking.