75-Archetype SyllabusBiology • ARCH-B-02 • Spec B2

Full 6-Card Lesson 15-Question Timed Drill

UAT-UK SPEC CODE: B2 (Movement across membranes)ASSUMED MATHS 1 PREREQUISITE: M3.10FREQUENCY: HIGH

Osmosis Water Potential Gradients, Active Transport & Cube SA:V Diffusion Ratios

Deconstructed from 17 past UAT-UK questions (7.3% of all historical Biology papers). Students using standard A-Level classroom methods spend an average of 130s on this archetype—blowing past the 90s ESAT budget. Using the 2-line Sub-90 heuristic below compresses solve time to 35s (saving 95s per question).

Historical Frequency

17 Past Qs

7.3% of Biology

Classroom Trap Time

130s

+40s over 90s budget

Sub-90 Target Time

35s

Banks +95s on the clock

Dominant UI Format

5-Option A–E

Maths 1 Skill: M3.10

Card 1 & Card 2 Preview: The Classroom Time Trap vs. Sub-90 2-Line Rule

Excerpted from our interactive 6-Step Topic Lesson for ARCH-B-02.

Launch All 6 Active-Recall Cards

CARD 1 OF 6 • THE CLASSROOM TIME TRAP (130s)

Why Students Bleed Time:

Calculate the surface area of all

6

faces:

\text{SA} = 6 \times 2^2 = 24\text{ cm}^2

. Calculate the volume:

V = 2^3 = 8\text{ cm}^3

. Divide

\text{SA}

V

\frac{24}{8} = 3\text{ cm}^{-1}

(~110s).

In 17 past UAT-UK questions (7.3% of Biology), candidates lose 95s by osmosis and diffusion are passive down a gradient (0 atp); only active transport uses carrier proteins + respiratory atp. Instead, apply B2 with Maths 1 skill M3.10.

CARD 2 OF 6 • THE 2-LINE SUB-90 HEURISTIC (<35s)

Line 1 (Cube Invariant): For any cube of side

L

\frac{\text{SA}}{V} = \frac{6L^2}{L^3} = \frac{6}{L}

**Line 2 (Substitute

L = 2

):**

\frac{6}{2} = 3\text{ cm}^{-1}

(20s).

Sanity & Limit Check: Verify units/signs against multi_statement_linchpin_foil (Statement claiming active transport is stopped by boiling/respiratory inhibitors because osmosis requires ATP) and factor_of_two_or_stoichiometry_trap (Calculating SA:V of a cube of side L as L² / L³ = 1/L instead of 6L² / L³ = 6/L).

Examiner Distractor Blueprint for ARCH-B-02

FOIL #1multi_statement_linchpin_foil

Statement claiming active transport is stopped by boiling/respiratory inhibitors because osmosis requires ATP

Osmosis and diffusion are passive down a gradient (0 ATP); only active transport uses carrier proteins + respiratory ATP.

Open Multi-Statement Linchpin Foil Clinic

FOIL #2factor_of_two_or_stoichiometry_trap

Calculating SA:V of a cube of side L as L² / L³ = 1/L instead of 6L² / L³ = 6/L

Using area of one face L² instead of total 6-face surface area 6L².

Open Factor-of-2 / Stoichiometry Clinic

FOIL #3sign_or_direction_flip

Saying water moves from high solute concentration to low solute concentration during osmosis

Inverting water potential: water moves from dilute (high water potential) to concentrated (low water potential) solution.

Open Sign / Direction Flip Clinic

FOIL #4intermediate_stop_trap

Calculating raw mass change Δm instead of percentage mass change (Δm / m_initial) * 100%

Comparing raw mass changes across potato cylinders that had different initial masses.

Open Intermediate Stop Trap Clinic

Try 1 Live Sample Question Under the 90-Second Stopwatch

Press W to open the 2-line dry-wipe scratchpad, select A–E, and lock in to reveal the Dual-View solution.

Full 6-Card Lesson Launch All 15 Questions (ARCH-B-02)

ARCH-B-02: Osmosis Water Potential Gradients, Active Transport & Cube SA:V Diffusion Ratios (Sample)Biology

00:00.0

SUB-90 ZONE (<35S)

0.0s35s Sub-9090s ESAT Budget150s Classroom

Question 1 of 1ARCH-B-02 (6-Card Lesson)Format: Standard 5-Option

Right-click any option to cross out • Keys A–E + Enter

Question 1 of 1 • 90s Target

Ready to Start Question 1?

The question stem, diagram, and answer options are hidden behind this pre-start gate. When you click below, the question will reveal and your 90-second split stopwatch will immediately begin ticking.

Biology•ARCH-B-02•Standard 5-Option

or press Enter to start