1、Development of Enquiry-Based Learning for Biology UndergraduatesAvailable through the Centre for Bioscience www.bioscience.heacademy.ac.uk/resources/projects/tierney.aspxEnquiry Based Learning teacher guidance notesIntroductionThe sessions in this booklet are intended to be used as a guide to enquir
2、y based learning (EBL) for first year biology students. Central to EBL is the notion that students are able to take on responsibility for themselves. This does not mean that they are left on their own the support of a staff mentor is paramount to the success of the students, especially first year st
3、udents who may be more used to looking to the teacher for all the answers.The exercises are not prescriptive. They can be changed to suit different classes. The nature of EBL is that the exercises should change, when tackled by different groups of students. It may be helpful to collect examples of w
4、hat the students discover, to build up a bank of examples, which in turn will inform the exercises in subsequent years.Some students may not have experience of EBL, or may feel uncomfortable not being told what to do. Communication is important in EBL, and informing students of the purposes of learn
5、ing through enquiry helps them come to terms with it, becoming independent, confident learners. Take some time to introduce students to EBL Listen to what students have to say Support students when they ask questions Help students formulate the questions which will help them find the answers Be enth
6、usiasticDevelopment of Enquiry-Based Learning for Biology UndergraduatesAvailable through the Centre for Bioscience www.bioscience.heacademy.ac.uk/resources/projects/tierney.aspxEnzymesLearning outcomes:By the end of the session students should be able to: Understand protein structure and function U
7、nderstand the biochemical mechanisms that allow enzymes to function Describe the action of specific enzyme(s) Understand denaturation of enzymesExercise 1: Introduction What is an enzyme? (Brainstorming session)Students should work in small groups to find the answer to this question. Students can st
8、art with a list of what they know about enzymes, as their top level categories. From this list, they can then discuss what they know in detail of each category.If possible allow them to write their answers on a large piece of paper or a board, to allow the whole group to see the answer. The students
9、 should be encouraged by a facilitator to produce a detailed answer. It may be helpful here to use a mind map, and have copies of textbooks or access to computers.Students can feedback within the group and the facilitator, and if time allows, feedback to the class, perhaps in the format that each gr
10、oup takes one area and feeds back to the class.Each group has a list of what they think an enzyme is, which can be combined to form a class list.Using this generated list, the groups can then go on to look at a specific example of an enzyme.Development of Enquiry-Based Learning for Biology Undergrad
11、uatesAvailable through the Centre for Bioscience www.bioscience.heacademy.ac.uk/resources/projects/tierney.aspxPossible answers: (not exhaustive)Enzymes are:ProteinsWhat is a protein?Structure primary structure, types of amino acids, pH- secondary structure, alpha helix, beta pleated sheet- tertiary
12、 structure- quaternary structure- bonds involved weak bonds, strong bondso H-bonds, ionic bonds, disulphide bridges, van der Waals forces- active site- shape- substrateFunction - substrate, product- active site- reaction how does substrate interact with active site? (bonds see above)- inhibition of
13、functionCatalystsMake reaction go faster how? Shape of active site interaction with substrate, chemical energy, rate of reactionWhat is the reaction that is catalysed by the enzyme?Chemical equation?Can the reaction be measured? How?Within the body effect of temperature and pH on enzyme activity? Op
14、timal conditions, what happens when these conditions are not met? (See above structure and function).Development of Enquiry-Based Learning for Biology UndergraduatesAvailable through the Centre for Bioscience www.bioscience.heacademy.ac.uk/resources/projects/tierney.aspxSpecific enzymesEach group ha
15、s a specific enzyme to study further. More than one approach can be taken here, depending on the time available. (a) students suggest enzymes of interest and each group chooses its own enzyme to research(b) students choose an enzyme from a prepared list(c) students are given an enzymes from a prepar
16、ed listApproach (a) gives students most freedom, but can cause problems if students opt for an obscure enzyme that they do not know much about. This could be tackled when there is an extended time for investigations to take place.(b) and (c) are similar in that the tutor has some degree of control o
17、ver the enzymes under investigation. For example, enzymes whose optimal conditions are not standard (pH 7 and 37C) could be used, to give students an appreciation of the variety of conditions that enzymes perform under.Examples are:Enzymes in the stomach: perform at low pHAcid phosphatase low pHAlka
18、line phosphatase high pHEnzymes that work at high/low temperaturesPlant enzymes e.g. RuBisCO, dependent on ambient temperatures enzyme has two functions balance between O2 and CO2 production.Catalase produced by tissues, but also by bacteria as protection against H2O2.Bromelain from pineapple, prote
19、ase digests protein, has the potential to digest itself does it protect itself? Does it attack its own molecules?In groups, students collect data to construct a picture of the enzyme, finding out as much as they can about structure and function. Using these molecules as examples shows the students t
20、hat not all enzymes function in standard conditions (pH 7 and 37C). Development of Enquiry-Based Learning for Biology UndergraduatesAvailable through the Centre for Bioscience www.bioscience.heacademy.ac.uk/resources/projects/tierney.aspxCalculationsCalculations can be introduced into the exercise.
21、This does not require the students to actually perform an experiment, but does rely on them making connections between chemistry and biology.Simple calculations can be made from the volume of products produced from a known starting volume of substrates.The example we have used here is for catalase:C
22、atalase a common enzyme in active tissues, also produced by some bacteria as a defence against hydrogen peroxide.If a small amount of catalase was added to 2ml of a 3% (w/v) H2O2 solution, what would be the volumes of the products of the reaction, assuming the reaction goes to completion?(You need t
23、o know the following:n=CV n=m/Mr1 mol gas at STP = 22.4lthe density of water)Calculation of amount of hydrogen peroxide in 2ml 3% H2O2 (w/v) solution3g/100ml H2O20.03g/ml0.06g H2O2 in 2mlCalculation of the number of moles of H2O2mol weight (H2O2) = 34n(H2O2) = 0.06/34=0.00176mol=1.76mmolComparison o
24、f stoichiometry of reaction - no. of moles of product2 H2O2 2 H2O + O2therefore 1.76mmol H2O0.88mmol O2Calculation of volume of O2 formed from starting product1 mol gas at STP = 22.4l0.88mmol O2= 0.00088mol0.00088 X 22.4 = 0.0197l or 19.7mlCalculation of volume of H2O formed from starting product1.7
25、6mmol H2O X 18g/mol=0.032g=0.032ml or 32lDevelopment of Enquiry-Based Learning for Biology UndergraduatesAvailable through the Centre for Bioscience www.bioscience.heacademy.ac.uk/resources/projects/tierney.aspxData handling methods of presentationHaving collected data about enzymes in general, a sp
26、ecific example of an enzyme, and some quantitative data, either from an experiment or data provided for the class, the students then discuss how to present the data.Students can discuss the following:What is required when presenting experimental data?- new, novel- replicable- backed up by literature
27、- careful analysis of data- not ignoring or discarding unusual dataWhat are the different methods of data presentation employed by scientists?Possible answers:Journal paperShort communicationLetterArticleBookPoster PresentationLooking at the list above, what are the differences between the different
28、 kinds of data presentation? When would the different methods be employed?What is the most appropriate way to present the data that your group has found?Development of Enquiry-Based Learning for Biology UndergraduatesAvailable through the Centre for Bioscience www.bioscience.heacademy.ac.uk/resource
29、s/projects/tierney.aspxMicroscopy of CellsFormat: 1 X 1 hour lecture 1X 2 hour practicalLecture:Before the lecture and the lab takes place, ask students to prepare answers to the following questions. What is the definition of a cell? What are the different components of a cell?Lecture outlineTiming
30、(min)Activity Description0-5 a Students, in groups of two or three, discuss answers to pre-lecture preparation.5-15 b Students feed back with answers, which are written on the board. Answers are expanded upon by the class, and given explanation/support/encouragement by lecturer.15-25 c Lecturer cons
31、olidates information about cells with the use of labeled diagrams from course text (Campbells Biology, 7th Edition). Students have printed notes with unlabelled diagrams which they can annotate. Reinforces activities a and b.25-50 d Description of and practice with calibrating scales.(i) Use a micro
32、scope with camera attachment to project an image of the stage micrometer on screen. The eyepiece graticule is substituted by a paper version stuck to the screen (eyepiece micrometer.doc enlarged by 140% twice on A3 paper, cut out and stuck together approximately 70cm long). Demonstrates to students
33、how to line up the two scales and the relationship between them. This is used to go through with the class the first calibration.(ii) Students have two scales of different sizes in their lecture notes (stage micrometer.doc and stage micrometer 2.doc). They are given an eyepiece scale printed on acet
34、ate (mulit-micrometer.doc) which they can use to perform another two calculations, feeding back the answer to the class in the lecture when they have completed the task.Development of Enquiry-Based Learning for Biology UndergraduatesAvailable through the Centre for Bioscience www.bioscience.heacadem
35、y.ac.uk/resources/projects/tierney.aspxLab practical:Timing (min)Activity Description0-5 a Introduction students are talked through the lab and given a list of pre-prepared slides which they will use for the lab.5-25 b Calibration of light microscope students work in pairs to carry out calibration o
36、f light microscope for real. Repeated for X4, X10 and X40. Assistance from GTAs and Lab Leader as necessary.25-35 c Choice of cell types Students are encouraged to think about the choice of cells from the list, and choose two different types of cell that they can look at and compare. They are asked
37、to justify their decision and check with a GTA before going forward. Reference books available in lab as a resource.35-100 d Students carry out investigation of two cell types. They are free to do as they please; some examples are given below: Measurement of cells Morphology Structure and functionAc
38、tivity supported by GTAs and Lab Leader.100-120e Students write up their findings. Examples given below: Comparison of size Comparison of structure Comparison of visible organellesActivity supported by GTAs and Lab Leader.100-120f Students look at fine structure of a cell using an electron micrograp
39、h. Compare this to the light microscope.Development of Enquiry-Based Learning for Biology UndergraduatesAvailable through the Centre for Bioscience www.bioscience.heacademy.ac.uk/resources/projects/tierney.aspxMicroscopy of Cells LabAims To introduce the use of the light microscope for studying cell
40、s To measure cells using a calibrated eyepiece graticuleObjectivesYou should be able to: identify and compare a number of different eukaryotic cells from different organisms accurately record what you see calibrate a light microscope using an eyepiece graticule and stage micrometer use the calibrate
41、d microscope to measure different cell typesLight MicroscopyInstructionsCalibration of the light microscopeYou have already had some practice calculating the calibrations for different magnifications. Today you are going to calibrate the light microscope using the stage micrometer and eyepiece grati
42、cule. You will need: A light microscope An eyepiece graticule (in the eyepiece lens) A stage micrometer1. Move the objective lens to the lowest power (X4).Development of Enquiry-Based Learning for Biology UndergraduatesAvailable through the Centre for Bioscience www.bioscience.heacademy.ac.uk/resour
43、ces/projects/tierney.aspx2. Place the stage micrometer on to the stage, making sure that it is in the slide holder correctly.3. Move the stage micrometer until it is directly under the objective lens, using the knobs at the right hand side of the stage to move it to the correct position.4. Focus the
44、 stage micrometer until you see both scales, superimposed on one another.5. Count the number of stage divisions equal to 100 eyepiece divisions.6. Calculate the distance between each eyepiece division.7. Repeat for X40 objective lens.X4 magnification 100 eyepiece divisions = _ *stage divisions We kn
45、ow that 100 stage divisions = 10mm 1 stage division = _mm _ *stage divisions = _mm 100 eyepiece divisions = _mm 1 eyepiece division = _ mm or _mX10 magnification 100 eyepiece divisions = _ *stage divisions We know that 100 stage divisions = 10mm 1 stage division = _mm _ *stage divisions = _mm 100 eyepiece divisions = _mm 1 eyepiece division = _ mm or _mX40 magnification 100 eyepiece divisions = _ *stage divisions We know that 100 stage divisions = 10mm 1 stage division = _mm _ *stage divisions = _mm 100 eyepiece divisions = _mm 1 eyepiece division = _ mm or _m
