diagram-bank

target	495+/500
author	Senior Sibling
name	diagram-bank
description	12th Grade Mandatory Diagram List (PCMB). Covers Physics Ray/Circuit diagrams, Biology Reproductive/Genetics structures, and Chemistry Mechanism visualizations.

Diagram Bank — 12th Grade "Mark-Magnet" Diagrams

In 12th Grade Science, a diagram is not an "option"—it is a Value Point. An answer without a diagram in Section E (5 Marks) is automatically capped at 4/5.

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🧬 Biology (The Most Diagram-Heavy)

1. Reproduction:
   • TS of Anther (showing 4 layers + Pollen sacs).
   • Mature Embryo Sac (7-celled, 8-nucleate).
   • Human Sperm (Head, Middle piece, Tail).
   • TS of Ovary/Testis.
2. Genetics & Molecular:
   • DNA Replication Fork (showing Leading/Lagging strands).
   • Lac Operon (Switch ON/OFF states).
   • tRNA Adapter Molecule (Clover leaf model).
3. Biotech & Human Health:
   • Antibody Molecule (Y-shaped with H and L chains).
   • Cloning Vector pBR322 (Mandatory: Mark all restriction sites).
   • Bioreactor (Simple Stirred-tank vs Sparged).

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🔭 Physics (Ray & Circuit Precision)

1. Optics:
   • Ray Diagram: Compound Microscope (Final image at $D$ and $\infty$).
   • Ray Diagram: Astronomical Telescope (Normal adjustment).
   • Wavefronts: Reflection and Refraction using Huygens' Principle.
2. Electricity & Magnetism:
   • Cyclotron (Dee structures and path).
   • Moving Coil Galvanometer (Internal parts).
   • AC Generator (Armature, Rings, Brushes).
3. Modern Physics:
   • Experimental setup of Photoelectric Effect.
   • Energy Level Diagram for Hydrogen atom (Lyman, Balmer, etc.).
   • P-N Junction: Forward and Reverse bias circuits.
   • Zener Diode as a Voltage Regulator.

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🧪 Chemistry (Visualizing Mechanisms)

1. Organic Mechanisms:
   • Transition state of $S_N 2$ reaction.
   • Carbocation formation in $S_N 1$.
2. Physical Chemistry:
   • Galvanic Cell ($Zn-Cu$ with Salt Bridge).
   • Standard Hydrogen Electrode (SHE).
   • Fuel Cell ($H_2-O_2$).
3. Biomolecules:
   • Structure of Glucose (Open vs Pyranose).
   • Peptide bond formation.

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✍️ Presentation Rules (Senior Sibling)

• The Box: Enclose your diagram in a neat pencil-drawn box.
• Single-Side Labeling: Draw all labels on the Right side with straight horizontal lines.
• Arrows: For Physics, arrows on light rays and current paths are Non-negotiable.
• Scale: A diagram should be roughly 1/3 of a page. Never draw "micro-diagrams".

Command Integration: Use /diagram-drill to get a list of diagrams to practice for a specific chapter.