A-Level Biology | Unit -3 | Core practical 1 | Part A | Semiquantitative technique

AS-Level Biology | Unit -3 | Core practical 1 | Semiquantitative technique

Unit 3: Practical Skills in Biology I

CORE PRACTICAL 1
Use a semi-quantitative method with Benedict’s reagent to estimate the concentrations of reducing sugars and with iodine solution to estimate the concentrations of starch, using colour standards

Introduction
Practical skills identified for assessment
Students are expected to develop experimental skills, and a knowledge and understanding of experimental techniques, by carrying out the core practicals and other recommended practical investigations and experiments while they study units 1 and 2. This will require them to work safely, produce valid results and present data in the most appropriate format.
This unit will assess students’ ability to apply their knowledge and understanding of experimental design, procedures and techniques developed throughout units 1 and 2.
• Solve problems set in practical contexts.
• Apply scientific knowledge to practical contexts.
• Comment on experimental design and evaluate scientific methods.
• Present data in appropriate ways.
• Evaluate results and draw conclusions with reference to
measurement uncertainties and errors.
• Identify variables, including those that must be controlled.
• Plot and interpret graphs.
• Process and analyse data using appropriate mathematical skills (see Appendix 6: Mathematical skills and exemplifications).
• Know and understand how to use a wide range of apparatus, materials and techniques safely, appropriate to the knowledge and understanding in this specification.
• Plan an investigation to test a hypothesis.
• Apply investigative approaches and methods to practical work.
• Use a range of practical equipment and materials safely and correctly.
• Follow written instructions.
• Make and record observations.
• Present information and data in a scientific way.
• Use appropriate software and tools to collect and process data.
• Use online and offline research skills, including websites, textbooks and other printed scientific sources of information.
• Cite sources of information correctly.
• Use a wide range of experimental and practical instruments, equipment and techniques appropriate to the knowledge and understanding included in this specification.

Plan an experiment
• identify the apparatus required
• identify the dependent and independent variables, standardised
or controlled variables
• describe how to measure relevant variables using the most appropriate instrument and correct measuring techniques
• identify and state how to control all other relevant variables to make it a fair test
• discuss whether repeat readings are appropriate
• identify health and safety issues and discuss how they may be
dealt with
• discuss how the data collected will be used
• identify possible sources of uncertainty and/or systematic error, and explain how they may be reduced or eliminated
• comment on the implications of biology (for example: benefits/risks) and on its context (for example: social/environmental/historical).


Implementation and measurements
• comment on the number of readings taken
• comment on the range of measurements taken
• comment on significant figures
• check a reading that is inconsistent with other readings – for example, a point that is not on the line of a graph
• comment on how the experiment may be improved, possibly by using additional apparatus (for example, to reduce errors).

Processing results
• perform calculations, using the correct number of significant figures
• plot results on a graph using an appropriate scale
• use the correct units throughout
• comment on the relationship obtained from the graph
• determine the relationship between two variables or determine a constant with the aid of a graph – for example, by determining the gradient using a large triangle
• suggest realistic modifications to reduce errors
• suggest realistic modifications to improve the experiment • discuss uncertainties, qualitatively and quantitatively.

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[biologyassess]

The level of glucose increases down the arrow 9:52

[rosenature]

Red orange shows the presence of more concentration of sugar in benedicts test … in this inference u have told blue is the highest concentration n red shows decreased concentration of glucose … pls recheck is it correct or reverse ??