ARCH-B-03: Mitosis vs. Meiosis Chromosome (2n/n) & DNA Mass (4c/2c/1c) Tracking + Stem Cell Potency

Full 15-Q Timed Drill

Step 1 of 6 • The Core Idea

ARCH-B-03: Why the 135s Classroom Method Fails Under the 90s Clock

Standard Classroom Method (Too Slow)~135s (Blows 90s Clock)

Start from the G1 somatic baseline

(2n = 78, 2c = 6.0\text{ pg})

. After S-phase replication, a cell enters Metaphase at

(2n = 78, 4c = 12.0\text{ pg})

. Mitosis yields

(2n = 78, 2c = 6.0\text{ pg})

; Meiosis I yields

(n = 39, 2c = 6.0\text{ pg})

; Meiosis II yields gametes at

(n = 39, 1c = 3.0\text{ pg})

. Thus the target stage has

39

chromosomes and

3.0\text{ pg}

of DNA (~120s).

The Fast ShortcutTarget: 35s (Saves 100s)

Line 1 (Pair Tracker): G1

= (78, 6.0) \xrightarrow{\text{S}} (78, 12.0)

.
Line 2 (Target Stage): mature sperm cell (after Meiosis II)

= (39\text{ chromosomes}, 3.0\text{ pg DNA})

(25s).

Where Students Lose Time: In 35 past UAT-UK questions (15.02% of Biology), candidates lose 100s by dna mass doubles (2c -> 4c) during s-phase, making each chromosome 2 sister chromatids, but chromosome count (centromeres) stays 2n = 46 until anaphase. Instead, apply B3 with Maths 1 skill M3.5.

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