Beatty Practical Notes Final (Pure Biology)

BEATTY SECONDARY SCHOOL A Distinguished Institution of Thinkers, Learners, Contributors Pure Biology (6093/03) Practical Notes Name: Class: Date:

Updated: Feb 2023 | Biology Unit 2 Pure Biology Practical Assessment Scientific subjects are, by their nature, experimental. It is therefore important that an assessment of your knowledge and understanding of Science should include a component relating to practical work and experimental skills. This assessment is provided in Paper 3 as a formal practical test: Total: 40 marks, 20% of examination Duration: 1 h 50 min Although the questions are different on each Paper 3, the number of marks assigned to each skill is always the same. This is shown in the table below. Skill Description Weighting Planning (P) • Identify key variables for a given question • Outline an experimental procedure to investigate the question • Describe how the data should be used to reach a conclusion • Identify the risks of the experiment and state the precautions that should be taken to keep risks to a minimum 15% Manipulation, measurement and observation (MMO) • Set up apparatus correctly by following written instructions or diagrams • Use common laboratory apparatus and techniques to collect data and make observations • Describe and explain how apparatus and techniques are used correctly • Make and record accurate observations with good details and measurements to an appropriate degree of precision • Make appropriate decisions about measurements or observations 25% Presentation of data and observations (PDO) • Present all information in and appropriate form • Manipulate measurements effectively for analysis • Present all quantitative data to an appropriate number of decimal places/significant figures 25% Analysis, conclusions and evaluation (ACE) • Analyse and interpret data or observations appropriately in relation to the task • Draw conclusion(s) from the interpretation of experimental data or observations and underlying principles • Make predictions based on their data and conclusions • Identify significant sources of errors and explain how they affect the results • State and explain how significant errors may be overcome or reduced, as appropriate, including how experimental procedures may be improved. 35%

Updated: Feb 2023 | Biology Unit 3 1.Biological Drawing Here, we are training your observational skills. You should learn to look very closely at a specimen, and use sound Biology knowledge to choose the structures to include or omit in your drawing. A good biological drawing should… • Be drawn using a sharp 2B pencil • Cover at least 2/3 of space given • Have a clean, clear and sharp outline • Have straight labeling lines drawn using ruler (Ideally, labels should all be on one side of the drawing. Label lines also should not cross or obscure the drawing.) • Have labels for all features of the drawing • Have an explanatory title that is underlined • Have accurate relative sizes of the structures drawn • Indicate the magnification at the bottom of the diagram Here is an example of a good biological drawing. Transverse Section of a Tomato Fruit Magnification = size of drawing (cm) / actual size (cm) x = 9.0 / 4.5 = 2.0 x (to 1 d.p.) (Pic: Lam, P. K., Lam, E. Y., & Lee, C. Y. (2007). G.C.E. O Level Biology Matters Practical Book. Singapore: Marshall Cavendish Education.)

Updated: Feb 2023 | Biology Unit 4 Here is an example of a poor biological drawing. (Pic: Lam, P. K., Lam, E. Y., & Lee, C. Y. (2007). G.C.E. O Level Biology Matters Practical Book. Singapore: Marshall Cavendish Education.) How to calculate the magnification of scientific drawing? magnification = In summary, have you gotten STAMP’D for approval? • Size – at least 2/3 of space provide • Title of drawing • Accuracy – showing all details • Magnification • Proportion • Drawing – sharp, clear lines size of drawing (cm) actual size (cm) x

Updated: Feb 2023 | Biology Unit 5 2.Tabulating Data When carrying out experiments, you will have to take down raw data – both qualitative and quantitative. It is therefore important for you present your data in a clear and logical manner. Quantitative data: It is a good practice to draw a table before you begin an experiment then enter the data straight into the table on collection. A good table should… • Have independent variable in the extreme left column • Have dependent variables or qualitative observations in the following columns • Clear headings with units • Not have units in the body of the table • Group measurements together if experiment is repeated (So that an average of the measurement can be later calculated) Here is an example of a good table. (Table: Lam, P. K., Lam, E. Y., & Lee, C. Y. (2007). G.C.E. O Level Biology Matters Practical Book. Singapore: Marshall Cavendish Education.) What are the three types of variables? The things that are changing in an experiment are called variables. There are three types of variables: • Independent variable is the factor that is ____________________________. • Dependent variable is the factor that ____________________________due to the varied factor. • Constant variables: parts of the experiment that are kept the ______________ in each test.

Updated: Feb 2023 | Biology Unit 6 Degree of accuracy You should use the correct number of significant figures when recording the results. All data should be written in tables to the same number of decimal places. This number would be determined by the precision of the instrument used to measure the data. The table shows some commonly used apparatus in the laboratory and the common accuracy values for each apparatus. Instrument Unit(s) Smallest division Data leave to… Weighing/mass balance g 0.01 g 2 d.p. 0.1 g 1 d.p. thermometer oC 1 oC 1 d.p. ruler mm, cm 0.1 cm 1 d.p. Stop watch s, min 0.01 s 2 d.p. 0.1 s 1 d.p. Measuring cylinder cm3 1 cm3 1 d.p. syringe cm3 [1 ml = 1 cm3] 0.2 cm3 1 d.p. (Table: Lam, P. K., Lam, E. Y., & Lee, C. Y. (2014). G.C.E. O Level Biology Matters Practical Book. Singapore: Marshall Cavendish Education.)

Updated: Feb 2023 | Biology Unit 7 Degree of accuracy for calculations The final answer for calculation should be left in the number of significant figure according to the raw data that is the least accurate. Example: Calculate the size of an object if the drawing is measured to be 24.6 cm and has a magnification of x25. size of real object = size of image / magnification size of real object = 24.6 / 25 = 9.84 ≈ 9.8 cm Qualitative data: It is presented in a descriptive format. It is good practice to use simple language that everyone can understand. Here are some examples of good qualitative data. Not so good observations Good observations (Universal indicator) The solution turned red. The solution turned from green to red. (Benedict’s test) The solution turned brick-red. Brick-red ppt was formed. (Limewater test) The solution turned milky / chalky. White ppt was formed. (Photosynthesis) Some parts of the leaf turned blue-black. The parts of the leaf that were originally green were stained blue-black. The parts of the leaf that were originally white were stained brown. (Iodine test) No change. Iodine solution remained brown. (Table: Lam, P. K., Lam, E. Y., & Lee, C. Y. (2014). G.C.E. O Level Biology Matters Practical Book. Singapore: Marshall Cavendish Education.) 3 s.f. 2 s.f. Answer left to 2 s.f. because in the raw data, the least number of s.f. is 2

Updated: Feb 2023 | Biology Unit 8 3.Plotting Graphs