B4 LIFE PROCESSES

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  • 1. B4 LESSON 1 & 2PROCESSESOF LIFE www.sciencetutors.zoomshare.com

2. ALIVE OR NOT ALIVE?YOUR TASK Ask each student to name one living thing andone non living thing. Write down answers under the column headings "Living" and "Non living". Next TaskDevelop criteria to decide if something is livingor non-living www.sciencetutors.zoomshare.com 3. LESSON 1 FEATURES OF LIVINGTHINGS Your Tasklist the basic processes of life carried out by all living thingswww.sciencetutors.zoomshare.com 4. Lesson Overview In this lesson, students learn about the characteristics that distinguish living thingsfrom non-living things. By examining seedBeetles students gather evidence and developcriteria to decide if something is living or non living.www.sciencetutors.zoomshare.com 5. IS IT ALIVE?In science, living is used to describe anything that isor has ever been aliveExamples dog, flower, seed, road kill, logNon living is used to describe anything that is not nownor has ever been aliveExamples include rock, mountain, glass, wristwatch. www.sciencetutors.zoomshare.com 6. WHAT MAKES YOU A LIVING THING?It is important for students begin to erode theirmisconceptions about living and non living things andto begin to understand that all living things grow,breathe, reproduce, excrete, respond to stimuli, andhave similar basic needs like nourishment. All livingthings are made up of cells.www.sciencetutors.zoomshare.com 7. MRS GRENThe following are features of all living things:Movement,Respiration,Sensing,Growth,Reproduction,Excretion andNutritionwww.sciencetutors.zoomshare.com 8. Planning Your InvestigationChallenge students to develop their ownmethods to test the preferences of seedbeetles. Plan an investigation to test your ideas www.sciencetutors.zoomshare.com 9. PLANNING YOUR INVESTIGATIONStudents plan and complete Activity AB4.1.1 Can seed beetles sense gravity?YOUR TASK is to demonstrate that simple organisms,such as seed beetles, are able to sense theirsurroundings. www.sciencetutors.zoomshare.com 10. ANALYSING RESULTSIn experiments the measurements are likely to vary.Students could be asked to suggest why they getdifferent values.Introduce the terms1. Repeatability and 2. Reproducibility.www.sciencetutors.zoomshare.com 11. EVALUATIONCan you comment on any improvements you could make tothe The way you did your test/investigation The accuracy of your readings/results Would you get the same results if you were to repeatyour investigation again? Why? Are your results enough to draw a firm conclusion?Explain why? Can you suggest any further work to extend yourinvestigation? www.sciencetutors.zoomshare.com 12. GCSE MAY 2009 Q2 13. ENZYMES AND pH Learning outcomes:At the end of this unit you should be able to1. Summarise the role of enzymes in livingorganisms2. Describe enzyme action in terms of activesite shape3. Describe the effect of pH on enzyme activityRECAP ENZYMES FROM PREVIOUS LESSON MODULE 1 www.sciencetutors.zoomshare.com 14. Quick QuizWhat are enzymes? What is the importance of enzymes forliving beings?What are the factors affecting the speedof EnzymesTurn to page 14-15 and 16-17 for answers. Remember you have 5 minutes to complete this task. 15. What Are Enzymes?Catalyst are substances that increases the speed of a chemical reaction.Enzymes are proteins that are catalysts of chemical reactions. 16. Factors Affecting The Speed Of Enzymes What are the main factors thatalter the speed of enzymatic reactions? 17. Factors Affecting The Speed OfEnzymesWhat are the main factors that alter the speed of enzymatic reactions?The main factors that change the speed of enzymatic reactions are temperature, pH and substrate concentration (quantity). 18. YOUR TASKWhat is meant by substrates ofenzymatic reactions? 19. DEMO EXPERIMENT Perform a brief demonstration to showthe effect of catalase (liver or potato) on hydrogen peroxide. Discuss the role ofcatalase in cells. 20. Students complete Activity AB4.2.1 Catalaseto collect oxygen from a known concentrationof hydrogen peroxide and yeast at differentpHs.Students could pool their results and calculatemean values. Discuss how the mean gives a goodestimate of the true value. 21. HINT ON DEMO EXPERIMENTStudents repeat the reaction three times to show theeffects of acid, alkali and neutral pH. This gives aqualitative indication of the effect of pH on enzymeaction.At this stage it is sufficient to deal with pH in terms ofacidic conditions, alkali conditions and neutral conditions. 22. REACTANTS AND PRODUCTSIntroduce the terms reactants and products inthe context of this particular enzyme.Conclusion: pH influences enzyme activity. 23. ENZYMES - SPEEDING UPHow does the enzyme speed up the reaction?Students look at the first two screens ofAnimation IB4.2.4 Enzymes to introduce the ideaof the lock-and-key model.Students complete Activity AB4.2.2 Lock-and-keymodel using Textbook Section B and AnimationIB4.2.4 Enzymes. 24. DifferentiationTo gather more quantitative results, studentscan be given yeast suspensions covering a rangeof specific pH values so that they can obtainresults to plot a graph of activity against pH.H: Use Activity AB4.2.2 sheet 1 Lock-and-keymodel.F: Use Activity AB4.2.2 sheet 2 Lock-and-keymodel. 25. GAS EXCHANGE -DIFFUSION Learning OutcomeTo describe how molecules get into and out of leaves To explain the processes of diffusion 26. INPUT AND OUTPUTList the inputs and outputs needed byliving organisms (food, gas exchange,wastes, etc.). 27. INPUT AND OUTPUTList the inputs and outputs needed byliving organisms (food, gas exchange,wastes, etc.). 28. Introduce diffusion as the way molecules get into and out of cells. 29. YOUR TASKDemonstrate diffusion in air by spraying a smallamount of air freshener at the front of the class. (Note:a) Have students raise their hands when they smell theair freshener.Time how long it takes to reach the back of the class.Fill the results into the table in Activity AB4.5.1Diffusion and calculate the speed of diffusion in air.Discuss how the molecules spread from an area of highconcentration to low concentration. 30. TRANSPORTATION IN CELLSYou could use the diffusion section of Animation IB4.5.4 Transport across cell membranes to illustrate diffusion across cell membranes. (Note: b) 31. PRACTICAL ACTIVITYStudents complete Activity AB4.5.1 Diffusion with aninvestigation of diffusion in water and in a gel. 32. PRACTICAL ACTIVITY Students complete Activity AB4.5.2 Gas exchange in plants: Looking at stomata in leavesStudents produce nail varnish imprints of theupper and lower surface of a leaf, allowing themto observe stomata and compare the numbers ineach surface.