Practical Assessment - A-Levels Biology
7 AS practical assessment
Practical work is at the heart of biology, so we have placed it at the heart of this specification.
Assessment of practical skills in this AS specification will be by written exams only.
The practical endorsement does not apply to the AS specification. A rich diet of practical work is essential to develop students’ manipulative skills and understanding of the processes of scientific investigation. It also contributes to teaching and learning of the concepts within this specification.
Questions in the papers have been written in the expectation that students have carried out at least the six required practical activities in section 7.2.
15% of the marks in the papers will relate to practical work.
7.1 Use of apparatus and techniques
All students taking this specification are expected to have carried out the required practical activities in section 7.2. These develop skills in the use of many of the following apparatus and techniques. This list is a compulsory element of the full A-level course. It is reproduced here for reference and to aid co-teaching the AS and A-level specifications.
| Apparatus and techniques | |
|---|---|
| AT a | use appropriate apparatus to record a range of quantitative measurements (to include mass, time, volume, temperature, length and pH) |
| AT b | use appropriate instrumentation to record quantitative measurements, such as a colorimeter or potometer |
| AT c | use laboratory glassware apparatus for a variety of experimental techniques to include serial dilutions |
| AT d | use of light microscope at high power and low power, including use of a graticule |
| AT e | produce scientific drawing from observation with annotations |
| AT f | use qualitative reagents to identify biological molecules |
| AT g | separate biological compounds using thin layer/paper chromatography or electrophoresis |
| AT h | safely and ethically use organisms to measure: • plant or animal responses • physiological functions |
| AT i | use microbiological aseptic techniques, including the use of agar plates and broth |
| AT j | safely use instruments for dissection of an animal organ, or plant organ |
| AT k | use sampling techniques in fieldwork |
| AT l | use ICT such as computer modelling, or data logger to collect data, or use software to process data |
7.2 Required practical activities
The following practicals must be carried out by all students taking this course. Written papers will assess knowledge and understanding of these, and the skills exemplified within each practical.
| Required activity | Apparatus and technique reference |
|---|---|
| 1. Investigation into the effect of a named variable on the rate of an enzyme-controlled reaction | a, b, c, f, l |
| 2. Preparation of stained squashes of cells from plant root tips; set-up and use of an optical microscope to identify the stages of mitosis in these stained squashes and calculation of a mitotic index | d, e, f |
| 3. Production of a dilution series of a solute to produce a calibration curve with which to identify the water potential of plant tissue | c, h, j, l |
| 4. Investigation into the effect of a named variable on the permeability of cell-surface membranes | a, b, c, j, l |
| 5. Dissection of animal or plant gas exchange or mass transport system or of organ within such a system | e, h, j |
| 6. Use of aseptic techniques to investigate the effect of antimicrobial substances on microbial growth | c, i |
Teachers are encouraged to vary their approach to these practical activities. Some are more suitable for highly structured approaches that develop key techniques. Others allow opportunities for students to develop investigative approaches. This list is not designed to limit the practical activities carried out by students. A rich practical experience for students will include more than the six required practical activities. The explicit teaching of practical skills will build students’ competence. Many teachers will also use practical approaches to the introduction of content knowledge in the course of their normal teaching.
7.3 Practical skills to be assessed in written papers
Overall, at least 15% of the marks for an AS Biology qualification will require the assessment of practical skills.
In order to be able to answer these questions, students need to have been taught, and to have acquired competence in, the appropriate areas of practical skills as indicated in the table of coverage below.
7.3.1 Independent thinking
| Practical skill | |
|---|---|
| PS 1.1 | Solve problems set in practical contexts |
| PS 1.2 | Apply scientific knowledge to practical contexts |
7.3.2 Use and application of scientific methods and practices
| Practical skill | |
|---|---|
| PS 2.1 | Comment on experimental design and evaluate scientific methods |
| PS 2.2 | Present data in appropriate ways |
| PS 2.3 | Evaluate results and draw conclusions with reference to measurement uncertainties and errors |
| PS 2.4 | Identify variables including those that must be controlled |
7.3.3 Numeracy and the application of mathematical concepts in a practical context
| Practical skill | |
|---|---|
| PS 3.1 | Plot and interpret graphs |
| PS 3.2 | Process and analyse data using appropriate mathematical skills as exemplified in the mathematical appendix for each science |
| PS 3.3 | Consider margins of error, accuracy and precision of data |
7.3.4 Instruments and equipment
| Practical skill | |
|---|---|
| PS 4.1 | Know and understand how to use a wide range of experimental and practical instruments, equipment and techniques appropriate to the knowledge and understanding included in the specification |
8 A-level practical assessment
Practical work is at the heart of biology, so we have placed it at the heart of this specification.
Practical assessments have been divided into those that can be assessed in written exams and those that can only be directly assessed whilst students are carrying out experiments.
A-level grades will be based only on marks from written exams.
A separate endorsement of practical skills will be taken alongside the A-level. This will be assessed by teachers and will be based on direct observation of students’ competency in a range of skills that are not assessable in written exams.
8.1 Use of apparatus and techniques
All students taking an A-level Biology qualification are expected to have had opportunities to use the following apparatus and develop and demonstrate these techniques. These apparatus and techniques are common to all A-level Biology specifications.
Carrying out the 12 required practicals in section 8.2 means that students will have experienced use of each of these apparatus and techniques. However, teachers are encouraged to develop students’ abilities by inclusion of other opportunities for skills development, as exemplified in the right-hand column of the content section of this specification.
| Apparatus and techniques | |
|---|---|
| AT a | use appropriate apparatus to record a range of quantitative measurements (to include mass, time, volume, temperature, length and pH) |
| AT b | use appropriate instrumentation to record quantitative measurements, such as a colorimeter or potometer |
| AT c | use laboratory glassware apparatus for a variety of experimental techniques to include serial dilutions |
| AT d | use of light microscope at high power and low power, including use of a graticule |
| AT e | produce scientific drawing from observation with annotations |
| AT f | use qualitative reagents to identify biological molecules |
| AT g | separate biological compounds using thin layer/paper chromatography or electrophoresis |
| AT h | safely and ethically use organisms to measure: • plant or animal responses • physiological functions |
| AT i | use microbiological aseptic techniques, including the use of agar plates and broth |
| AT j | safely use instruments for dissection of an animal organ, or plant organ |
| AT k | use sampling techniques in fieldwork |
| AT l | use ICT such as computer modelling, or data logger to collect data, or use software to process data |
8.2 Required practical activities
The following practicals must be carried out by all students taking this course. Written papers will assess knowledge and understanding of these, and the skills exemplified within each practical.
| Required activity | Apparatus and technique reference |
|---|---|
| 1. Investigation into the effect of a named variable on the rate of an enzyme-controlled reaction | a, b, c, f, l |
| 2. Preparation of stained squashes of cells from plant root tips; set-up and use of an optical microscope to identify the stages of mitosis in these stained squashes and calculation of a mitotic index | d, e, f |
| 3. Production of a dilution series of a solute to produce a calibration curve with which to identify the water potential of plant tissue | c, h, j, l |
| 4. Investigation into the effect of a named variable on the permeability of cell-surface membranes | a, b, c, j, l |
| 5. Dissection of animal or plant gas exchange or mass transport system or of organ within such a system | e, h, j |
| 6. Use of aseptic techniques to investigate the effect of antimicrobial substances on microbial growth | c, i |
| 7. Use of chromatography to investigate the pigments isolated from leaves of different plants, eg leaves from shade-tolerant and shade-intolerant plants or leaves of different colours | b, c, g |
| 8. Investigation into the effect of a named factor on the rate of dehydrogenase activity in extracts of chloroplasts | a, b, c |
| 9. Investigation into the effect of a named variable on the rate of respiration of cultures of single-celled organisms | a, b, c, i |
| 10. Investigation into the effect of an environmental variable on the movement of an animal using either a choice chamber or a maze | h |
| 11. Production of a dilution series of a glucose solution and use of colorimetric techniques to produce a calibration curve with which to identify the concentration of glucose in an unknown ‘urine’ sample | b, c, f |
| 12. Investigation into the effect of a named environmental factor on the distribution of a given species | a, b, h, k, l |
Teachers are encouraged to vary their approach to these practical activities. Some are more suitable for highly structured approaches that develop key techniques. Others allow opportunities for students to develop investigative approaches. This list is not designed to limit the practical activities carried out by students. A rich practical experience for students will include more than the 12 required practical activities. The explicit teaching of practical skills will build students’ competence. Many teachers will also use practical approaches to the introduction of content knowledge in the course of their normal teaching. Students’ work in these activities can also contribute towards the endorsement of practical skills.
8.3 Practical skills to be assessed in written papers
Overall, at least 15% of the marks for an A-level Biology qualification will require the assessment of practical skills.
In order to be able to answer these questions, students need to have been taught, and to have acquired competence in, the appropriate areas of practical skills as indicated in the table of coverage below.
8.3.1 Independent thinking
| Practical skill | |
|---|---|
| PS 1.1 | Solve problems set in practical contexts |
| PS 1.2 | Apply scientific knowledge to practical contexts |
8.3.2 Use and application of scientific methods and practices
| Practical skill | |
|---|---|
| PS 2.1 | Comment on experimental design and evaluate scientific methods |
| PS 2.2 | Present data in appropriate ways |
| PS 2.3 | Evaluate results and draw conclusions with reference to measurement uncertainties and errors |
| PS 2.4 | Identify variables including those that must be controlled |
8.3.3 Numeracy and the application of mathematical concepts in a practical context
| Practical skill | |
|---|---|
| PS 3.1 | Plot and interpret graphs |
| PS 3.2 | Process and analyse data using appropriate mathematical skills as exemplified in the mathematical appendix for each science |
| PS 3.3 | Consider margins of error, accuracy and precision of data |
8.3.4 Instruments and equipment
| Practical skill | |
|---|---|
| PS 4.1 | Know and understand how to use a wide range of experimental and practical instruments, equipment and techniques appropriate to the knowledge and understanding included in the specification |
8.4 Practical skills to be assessed via endorsement
8.4.1 Cross-board statement on practical endorsement
The assessment of practical skills is a compulsory requirement of the course of study for A-level qualifications in biology, chemistry and physics. It will appear on all students’ certificates as a separately reported result, alongside the overall grade for the qualification. The arrangements for the assessment of practical skills will be common to all awarding organisations. These arrangements will include:
- A minimum of 12 practical activities to be carried out by each student which, together, meet the requirements of Appendices 5b (Practical skills identified for direct assessment and developed through teaching and learning) and 5c (Use of apparatus and techniques) from the prescribed subject content, published by the Department for Education (DfE). The required practical activities will be defined by each awarding organisation.
- Teachers will assess students against Common Practical Assessment Criteria (CPAC) issued jointly by the awarding organisations. The CPAC below are based on the requirements of Appendices 5b and 5c of the subject content requirements published by the DfE, and define the minimum standard required for the achievement of a pass.
- Each student will keep an appropriate record of their practical work, including their assessed practical activities.
- Students who demonstrate the required standard across all the requirements of the CPAC will receive a ‘pass’ grade.
- There will be no separate assessment of practical skills for AS qualifications.
- Students will answer questions in the AS and A-level exam papers that assess the requirements of Appendix 5a (Practical skills identified for indirect assessment and developed through teaching and learning) from the prescribed subject content, published by the DfE. These questions may draw on, or range beyond, the practical activities included in the specification.
8.4.2 Criteria for the assessment of practical competency in A-level Biology, Chemistry and Physics
| Competency | Practical mastery |
|---|---|
| In order to be awarded a Pass a student must, by the end of the practical science assessment, consistently and routinely meet the criteria in respect of each competency listed below. A student may demonstrate the competencies in any practical activity undertaken as part of that assessment throughout the course of study. Students may undertake practical activities in groups. However, the evidence generated by each student must demonstrate that he or she independently meets the criteria outlined below in respect of each competency. Such evidence: • (a) will comprise both the student’s performance during each practical activity and his or her contemporaneous record of the work that he or she has undertaken during that activity, and • (b) must include evidence of independent application of investigative approaches and methods to practical work. | |
| 1. Follows written procedures | (a) Correctly follows written instructions to carry out experimental techniques or procedures. |
| 2. Applies investigative approaches and methods when using instruments and equipment | (a) Correctly uses appropriate instrumentation, apparatus and materials (including ICT) to carry out investigative activities, experimental techniques and procedures with minimal assistance or prompting. (b) Carries out techniques or procedures methodically, in sequence and in combination, identifying practical issues and making adjustments where necessary. (c) Identifies and controls significant quantitative variables where applicable, and plans approaches to take account of variables that cannot readily be controlled. (d) Selects appropriate equipment and measurement strategies in order to ensure suitably accurate results. |
| 3. Safely uses a range of practical equipment and materials | (a) Identifies hazards and assesses risks associated with those hazards, making safety adjustments as necessary, when carrying out experimental techniques and procedures in the lab or field. (b) Uses appropriate safety equipment and approaches to minimise risks with minimal prompting. |
| 4. Makes and records observations | (a) Makes accurate observations relevant to the experimental or investigative procedure. (b) Obtains accurate, precise and sufficient data for experimental and investigative procedures and records this methodically using appropriate units and conventions. |
| 5. Researches, references and reports | (a) Uses appropriate software and/or tools to process data, carry out research and report findings. (b) Cites sources of information demonstrating that research has taken place, supporting planning and conclusions. |