A-LevelBiologyThe mitotic cell cycleMay/June 2021Paper 1 Q191 Mark
A single skin cell was isolated and transferred to growth medium in a sterile Petri dish. The Petri dish was incubated for 16 days. During this time, the number of skin cells multiplied as a result of repeated mitotic divisions. One of the chromosomes in the nucleus of each skin cell has a telomere that contains many repeats of the base sequence TTAGGG. On each of days 4, 8, 12 and 16 of the incubation period, a single cell was removed from the Petri dish. The total number of bases in the telomere of this chromosome was determined for each cell. Each of the four cells had a different total number of telomere bases for this chromosome: 5548, 5580, 5645 and 5700. What was the total number of telomere bases in the chromosome from the cell that had undergone the most mitotic divisions?
A5548
B5580
C5645
D5700
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The correct answer is A. This question tests the candidate's understanding of the mitotic cell cycle within the Biologysyllabus. The examiner's mark scheme requires...
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