TOPIC: MACROMOLECULES AND DIGESTION

PURPOSE

Digestive enzymes are responsible for the breakdown of complex macromolecules within the body. Once consumed, food is broken down in three important stages ~

Mechanical or Physical DigestionBreaks food into smaller pieces = affects the SA/V Ratio. This process has no effect on the food chemistry it merely breaks it up physically;

Chemical DigestionMixes the physically broken down food with digestive enzymes which dissolve it chemically and break it down into smaller simpler molecules. Enzymes are produced by glands which open to the gut.

AbsorptionThe process of how simple molecules are absorbed into the bloodstream so that nutrients from food are able to reach the cells of the body.

Along the alimentary canal various digestive enzymes work to chemically breakdown food. This assessment provides you with the opportunity to deconstruct the question ‘How can the action of a digestive enzyme be modelled in a practical investigation?’ and design a practical to investigate enzyme action.

This task will enable you to demonstrate your ability to: Research a biological question to design a testable investigation Select and acknowledge information about biology from different sources Formulate hypotheses Conduct an investigation Identify variables and obtain and record data which is then analysed, and interpreted Evaluate results, form conclusions, and communicate understanding Use appropriate biological terms, conventions, formulae and equations Suggest improvements Communicate knowledge and understanding of biology

DESCRIPTION OF TASK

You must design an experiment to investigate a factor that affects enzyme action. You will have the following materials to work with as a minimum;

MATERIALS 5% lipase solution Phenolphthalein Full fat milk 0.05 mol per L Sodium carbonate solution Water Bath Thermometer Test tubes and Racks Ice Glass wear (accessed by you) Timer of your choice

A LOG OF ALL ASPECTS OF THIS PRACTICAL INVESTIGATION MUST BE SUBMITTED ON THE COMPLETION OF THE PRACTICAL AS AN APPENDIX

Design an investigation to explore a factor that affects enzyme action!STAGE 1 BIOLOGY

Part A: Deconstruct the Question (1 week)

Conduct research to answers the question ‘How can the action of a digestive enzyme be modelled in a practical investigation?’.

Conduct research individually into practical investigations that model enzyme action.

Design a flowchart of all possibilities honing in on a single design and critique your rationale.

Include a description of a range of possibilities that interrogates both the biological imperative (e.g.

digestion, physical, chemical, absorption, enzyme action) and investigation skills (e.g. sample size,

resolution). This list is not exhaustive but provides a springboard to start from.

Concisely summarise the research findings to answers the question ‘How can the action of a digestive enzyme be modelled in a practical investigation?’ not exceeding a page.

DEMO

REACTION 1: Phenolphthalein is an indicator that is pink in alkaline solutions of about pH10. When the pH drops below pH 8.3 phenolphthalein goes colourless. Here, an alkaline solution of milk, lipase and phenolphthalein will change from pink to colourless as the fat in milk is broken down to form fatty acids (and glycerol) thus reducing the pH to below 8.3. The time taken for this reaction to occur is affected by temperature.

SOURCE: Investigating effect of temperature on the activity of lipase | Nuffield FoundationNuffieldfoundation.org. (2017).  Investigating effect of temperature on the activity of lipase | Nuffield Foundation. [online] Available at: http://www.nuffieldfoundation.org/practical-biology/investigating-effect-temperature-activity-lipase [Accessed 9 Aug. 2017].

REACTION 2: Measure the time taken for amylase to completely break down starch, by withdrawing samples at 10 second intervals and noting the time at which the solution no longer gives a blue-black colour with iodine solution (but the iodine solution remains orange). Use buffers to provide solutions at a different pH. Calculate the rate of this enzyme controlled reaction by calculating 1÷ time.

SOURCE: Nuffieldfoundation.org. (2017).  Investigating the effect of pH on amylase activity | Nuffield Foundation. [online] Available at: http://www.nuffieldfoundation.org/practical-biology/investigating-effect-ph-amylase-activity [Accessed 9 Aug. 2017].

Formulate a small group with other class members to discuss reaction and potential factors to

manipulate. Use the scientific method planning sheet to assist you

Determine all possible IVs and all possible DVs

Articulate CVs predict the implications if each is NOT controlled (relate to reliability, accuracy,

precision and validity)

Determine the resolution of apparatus you could use and sample size.

Part B: Investigation Design (1 week)

Timeline of InvestigationSTAGE 1 BIOLOGY

Design an experiment individually to investigate a factor that affects enzyme action.

Demonstrate your knowledge and application of the background theory relating to this investigation in an introduction.

Write a testable hypothesis and aim Identify the independent, dependent, and controlled variables. Produce a materials list and complete a risk assessment to the Lab Technicians Prepare a list of materials and a detailed method to test the hypothesis. Consider ethics, safety and risk assessment

CONDITIONS: You will have four lessons to design a practical + homework time

SUBMIT Section A by lesson end Monday Week 6

Part C: Practical Component (Double Lesson Week 7)

Within your group/class decide on the investigation design you wish to undertake. Conduct the experiment in the double lesson making any necessary adjustments. You will have the entire double lesson to conduct the investigation and collect necessary data. Record your results in a data table and graph the results appropriately. Describe the pattern / trend in the data.

CONDITIONS: Share designs, select prac based on reliability and reproducibility during a single lesson.

Prepare data table ready for next lesson when you will conduct the practical gathering data – remember sample size!

Part D: Written Component & DUE date

Present Results table, graph, Pattern and Trend Write a discussion and conclusion for the investigation that you carried out. Maintain/Update LOG OF ACTIVITIES

CONDITIONS: Submit Draft Friday Week 8 DUE Friday Week 9

No Teacher Feedback Before Final Submission.

ENZYME SUMMATIVE PRACTICAL INVESTIGATIONS FOLIO SCHOOL NUMBER 308 SACE NUMBER : TASK DESCRIPTION CHECKLIST ASSESSMENT

DEISGN CRITERIAGRADE

DECONSTRUCTION

Research findings to answers the question ‘How can the action of a digestive enzyme be modelled in a practical investigation?’ not exceeding a page.

In addition, construct a flowchart of all possibilities honing in on a single investigation design and critique your rationale. Include a description of a range of possibilities that interrogates both the biological imperative and investigation skills.

KA2 Max 1 page

INTRODUCTION

Demonstrate your knowledge and application of the background theory relating to this investigation

Outline the different factors that could be investigated in this investigation Design a biological investigation to assess the effect of one factor by ~

Stating the purpose of the investigation (aim) Stating a testable hypothesis Identifying the independent and dependent variables Identifying conditions that are kept constant Explaining what results will support or refute the hypothesis

KA 1 300 words

MATERIALS & METHOD

Design a biological investigation to include ~ The procedure to be carried out (include manipulation of apparatus and

technological tools) Labelled diagrams of your apparatus Safe working procedures & risk assessment Individual and collaborative work Maintaining precision & accuracy

IAE1

KA4

DATA PRESENTATION

Present data in table form. Include a title, column headings (including correct units of measure /symbols used, record data to the appropriate resolution (e.g. Decimal places)

Plot a Graph of the dependent variable (y axis) versus the independent variable (x axis). Label x and y axis, include units of measure / symbols

Describe the pattern or trend Draw a line or curve of ‘best fit’, that shows the pattern in the results (points should be

scattered evenly above and below the line) Labelled photographic images

IAE2

KA4400 words

DISCUSSION

Analysis of ErrorsIdentify sources of error and label them as random or systematic errorsSuggest cause and improvements

Analysis of ProceduresComment on sample sizeDiscuss averaging Analysis of method.

IAE3

IAE4 600 words

CONCLUSION

State what was found out and use scientific knowledge to explain the result. State whether the hypothesis was supported or refuted.

IAE3 200 words

REFERENCE

Clearly acknowledge your sources of information following the correct conventions. KA4

COMMUNICATION

Record the ‘minutes’ from your group meetings, before and after implementation of the investigation.

Your report should be logical, clear and use scientific language and terminology You should write in the third person i.e.; ‘The temperature was measured’ instead of ‘I

measured the temperature’. Your report should communicate knowledge and understanding of biology in different

formats

KA1

KA2