Biology 9700 Practical Notes

Paper 3 is worth 40 marks and typically lasts two hours, requiring you to complete 2-3 questions focusing on:

| Time / s | Temperature / °C | pH | Reading 1 / mm | Reading 2 / mm | | :--- | :--- | :--- | :--- | :--- | | 0 | 20.0 | 7.0 | 12.0 | 11.5 | | 30 | 21.5 | 7.0 | 14.0 | 13.5 |

: Use a sharp pencil for clear, unbroken lines (no "feathering" or sketching). Label with straight, horizontal lines that do not cross. 2. Core Experimental Skills

Always use a sharp pencil, clear lines, and draw only what you see (not a textbook diagram). Label structures clearly and state the magnification used. B. Food Tests (Biochemical Analysis)

Add iodine in potassium iodide solution. A blue-black color indicates starch. Enzyme Kinetics Experiments usually involve catalase, amylase, or protease. biology 9700 practical notes

Always use a water bath; never heat test tubes directly over a Bunsen flame to prevent bumping. Non-Reducing Sugars Test (Sucrose) Procedure: Heat a fresh sample with dilute Hydrochloric Acid (

) Test: Compares observed categorical data against expected genetic phenotypic ratios.

Must include the quantity and the unit separated by a slash (e.g., Temperature / °C Consistency:

Misreading a meniscus or scale by looking at it from an angle. Standard Improvements Paper 3 is worth 40 marks and typically

Master Your AS Level Biology Practical: The Ultimate 9700 Guide

When asked to write a practical method, structure your answer around these core points:

You must be able to perform and interpret these five standard tests flawlessly: Positive Result Heat Required? Benedict’s Solution →right arrow →right arrow →right arrow Yes (80°C+) Non-Reducing Sugars HCl (hydrolysis), then Benedict’s Starch Iodine in KI Blue-Black Proteins Biuret Reagent Purple/Violet Lipids Ethanol (Emulsion test) Milky White Emulsion 3. Enzyme Experiments & Variables

Paper 5 is the "dry lab" (written exam). Notes here are arguably more valuable than Paper 3 notes because they teach exam technique. Core Experimental Skills Always use a sharp pencil,

Used when concentrations decrease exponentially (e.g., 10%, 1%, 0.1%, 0.01%). Each step is diluted by the same factor (usually a factor of 10 or a factor of 2). Set up 5 test tubes. Add of distilled water to tubes 2, 3, 4, and 5. of the 10% stock solution to tube 1. from tube 1 to tube 2. Mix thoroughly. (Tube 2 is now 5%).

Substrate disappearance: Take samples at 30-second intervals and mix with iodine to determine when starch is completely broken down (achieving a constant yellow-brown color).

: Focus on 3–4 representative cells. Use clear, continuous lines and do not use shading or "fuzzy" sketching.