Biology 9700 Practical Notes Now

You need to know when to use which test.

  • Student’s T-test: Comparing the means of two groups (e.g., Height of plants in sun vs. shade).
  • Correlation Coefficient (Spearman’s Rank): Looking for a relationship between two variables (e.g., Temperature vs. Enzyme rate).

    • When writing a plan (for a 15-mark question), follow this rigid structure:

    Good luck! Remember, the examiner doesn't care if your drawing looks like a work of art; they care if the lines attach to the right place and you calculated the magnification correctly.

    Have a specific practical skill you struggle with? Drop a comment below! biology 9700 practical notes

    To prepare for the Biology 9700 Paper 3 practical, you need to master three main areas: experimental techniques, microscopy, and data presentation. 1. Essential Experimental Techniques Most Paper 3 exams focus on these core procedures:

    Serial Dilutions: Understand both proportional and semi-logarithmic dilutions to create ranges of concentrations for enzyme or osmosis experiments.

    Qualitative Food Tests: Memorize the reagents and positive results for: Benedict’s test (reducing/non-reducing sugars) Iodine (starch) Biuret (protein) Emulsion test (lipids). You need to know when to use which test

    Variable Management: Clearly identify your Independent Variable (what you change), Dependent Variable (what you measure), and Controlled Variables (what you keep the same to ensure validity). 2. Microscopy and Biological Drawings The second question almost always involves a microscope.

    Calibration: Know how to calibrate an eyepiece graticule using a stage micrometer.

    Plan Diagrams: These are low-power drawings. Use a sharp HB pencil, draw unbroken lines, and do not draw individual cells. Focus on tissue layers like xylem, phloem, and epidermis. Student’s T-test: Comparing the means of two groups

    High-Power Drawings: Draw a few individual cells. Include the nucleus but do not shade it. Magnification Formula:

    (Image size / Actual size). Always use the same units (usually 3. Data Presentation & Evaluation

    Tables: Use neat, ruled lines. The independent variable goes in the first column. Include units only in the headings, never in the body (e.g., Temperature / °C).

    Graphs: The independent variable is on the x-axis and the dependent on the y-axis. Use a linear scale and ensure points are plotted accurately with a small 'x' or dot-in-circle.

    Errors and Improvements: Be ready to distinguish between systematic errors (instrumental) and random errors (human/procedural). Common improvements include using more precise equipment (e.g., a colorimeter) or increasing the number of intermediate concentrations. Recommended Revision Resources