2022 CHS Biology Practical Notes

CATHOLIC HIGH SCHOOL DEPARTMENT OF SCIENCE PRACTICAL ASSESSMENT REVISION KIT FOR BIOLOGY 2022 CONTENTS I. PRACTICAL INFORMATION SHEET Page 2 II. NOTES ON COMPETENCIES SKILLS Page 5 III. SOLUTIONS TO EXERCISES Page 39 IV. PRACTICE QUESTIONS Page 44 V. MARK SCHEME TO PRACTICE QUESTIONS Page 56 VI. APPENDICES Page 61 This revision kit only serves as a supplement to the practical file containing the weekly practical tasks. Revise the practical file prior to assessment.

CHS | Adapted by Mr. Lee Joon Kiat | Updated Nov 2019 Page | 2 PRACTICAL ASSESSMENT Paper 3 (1 h 50 min, 40 marks) This paper will comprise two or three compulsory practical questions, based mainly on experimental skills and investigations.  Planning (P)  Manipulation, measurement and observation (MMO)  Presentation of data and observations (PDO)  Analysis, conclusions and evaluation (ACE) One or more of the questions may incorporate assessment of Planning (P) and require candidates to apply and integrate knowledge and understanding from different sections of the syllabus. The assessment of PDO and ACE may include questions on data-analysis which do not require practical equipment and apparatus. The assessment of Planning (P) will have a weig hting of 15%. The assessment of skill areas MMO, PDO and ACE will have a weighting of 85%. This accounts for 20% of the total weighting in the subject for the GCE O-Level assessment. Candidates are not allowed to refer to notebooks, textbooks or any other information during the assessment.

CHS | Adapted by Mr. Lee Joon Kiat | Updated Nov 2019 Page | 3 COMPETENCY LIST (A) Planning (P) Candidates should be able to (A1) identify key variables for a given question/problem (A2) outline an experimental procedure to investigate the question/problem (A3) describe how the data should be used in order to reach a conclusion (A4) identify the risks of the experiment and state precautions that should be taken to keep risks to a minimum (B) Manipulation, measurement and observation (MMO) Candidates should be able to (B1) set up apparatus correctly by following written instructions or diagrams (B2) use common laboratory apparatus and techniques to collect data and make observations (B3) describe and explain how apparatus and techniques are used correctly (B4) make and record accurate observations with good details and measurements to an appropriate degree of precision (B5) make appropriate decisions about measurements or observations (C) Presentation of data and observations (PDO) Candidates should be able to (C1) present all information in an appropriate form (C2) manipulate measurements effectively for analysis (C3) present all quantitative data to an appropriate number of decimal places/ significant figures (D) Analysis, conclusions and evaluation (ACE) Candidates should be able to (D1) analyse and interpret data or observations appropriately in relation to the task (D2) draw conclusion(s) from the interpretation of experimental data or observations and underlying principles (D3) make predictions based on their data and conclusions (D4) identify significant sources of errors and explain how they affect the results (D5) state and explain how significant errors may be overcome or reduced, as appropriate, including how experimental procedures may be improved.

CHS | Adapted by Mr. Lee Joon Kiat | Updated Nov 2019 Page | 4 Candidates may be asked to carry out exercises comprising: 1. simple physiological experiments, involving tests for food substances, enzyme reactions, hydrogencarbonate indicator solution, cobalt(II) chloride paper and so on; 2. simple physiological experime nts, involving the use of sharp instruments on plant or animal materials (accurate observations of these specimens will need a hand lens of not less than ×6 magnification for each candidate); 3. manipulative skills in assembling apparatus, in using chemical reagents and in using such instruments as mounted needles, scalpels and razor blades, forceps and scissors; 4. measurements using appropriate instruments (e.g. thermometer, syringe, measuring cylinder, ruler and so on) and simple arithmetical calculations; 5. familiar and unfamiliar techniques to record observations and make deductions from them; 6. recognition and observation of features of familiar and unfamiliar biological specimens, recording observations and making deductions about functions of whole specimens or their parts; and 7. clear line drawings of the specimens provided, indicating magnification and labelling familiar structures. This is not intended to be an exhaustive list. Candidates are expected to be familiar with the use of data-loggers. Assessment of Skill P may include the appropriate use of data-loggers.

CHS | Adapted by Mr. Lee Joon Kiat | Updated Nov 2019 Page | 5 NOTES ON COMPETENCIES SKILLS COMPETENCIES Page(s) Planning (P) identify key variables for a given question/problem 6-7 outline an experimental procedure to investigate the question/problem describe how the data should be used in order to reach a conclusion identify the risks of the experiment and state precautions that should be taken to keep risks to a minimum 8 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 9 describe and explain how apparatus and techniques are used correctly 10 make and record accurate observations with good details and measurements to an appropriate degree of precision 10-17 make appropriate decisions about measurements or observations Presentation of data and observations (PDO) present all information in an appropriate form 18-27 manipulate measurements effectively for analysis 28-30 present all quantitative data to an appropriate number of decimal places/ significant figures Analysis, conclusions and evaluation (ACE) analyse and interpret data or observations appropriately in relation to the task 30-34 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 35-38 state and explain how significant errors may be overcome or reduced, as appropriate, including how experimental procedures may be improved

CHS | Adapted by Mr. Lee Joon Kiat | Updated Nov 2019 Page | 6 (A) Planning (P) (A1) Identify key variables for a given question/problem  What variables should I change, measure and keep constant? Name of variable Meaning Independent This is the variable that you deliberately change to observe what effect it has. Dependent This is the variable that you measure. It is the variable that you think will change because you have changed the independent variable. Controlled This is a variable or variables that you should keep constant, so that any test you do is a fair test. (A2) Outline an experimental procedure to investigate the question/problem  What is the control setup, if required?  What techniques should I use?  How should the variables be manipulated e.g. measured/ varied/ kept constant?  What are the instruments I need?  How many repeats should I do? (To take average)  What is a suitable range and interval? (A3) Describe how the data should be used in order to reach a conclusion  How should I interpret the data?  Are there any calculations I need to make?  What is the best way to present my findings? Worked example