BIO Lab Assignment – Photosynthesis and Respiration (2015)

09 Jun BIO Lab Assignment – Photosynthesis and Respiration (2015)

Question
Photosynthesis and Respiration

Margaret E. Vorndam, M.S.

Version42-0103-00-01

Lab Report Assistant

Thisdocumentisnotmeanttobeasubstitute foraformallaboratoryreport.TheLabReport Assistantissimplyasummaryoftheexperiment’squestions,diagramsifneeded,anddatatables that shouldbeaddressedinaformallabreport. Theintentistofacilitatestudents’writing oflab reports by providing this informationin an editable filewhich can be sent to an instructor.

Observations

Data Table 1: Rf Value Comparison for Chlorophyll Pigments

Chlorophyll

Pigment

Observed

Color

Distance to top ofpigment,mm

Rf

Other Students’ Rf

Average

# of Rf Results Averaged from other Students (N)

Top of Solvent

Front

NA

Carotenoids

Xanthophylls

Chlorophyll a

Chlorophyll b

Distancetotopofpigment,mm:Measurefromwherethetopofthesolventextractlevel

intersectedthepaperchromatographtothetopmostlevelofthecolor.Thenmeasurethis

distance to the top of the solvent front and record.

Data Table 3: Gross Photosynthesis in Elodea

Rates

Distance of travel, mm

Net Photosynthesis Rate over 10 minutes

= mm of movement from marked beginning point on bent

tube to end point after10 minutes

RespirationRate over 10 minutes

= mm of movement from marked end point on bent tube

toward beginning point after10 minutes

Gross Photosynthesis over 10 minutes

(= mm Net Photosynthesis + mm Respiration)*

Rate of Photosynthesis over one hour

(= Gross Photosynthesis ÷ 10 minutes x 60 minutes)

*Was respirationoccurring during photosynthesis? Add back the O2that was consumed by plant respirationto obtain the total photosyntheticrate.

Data Table 4: Comparison of PhotosyntheticRate

My PhotosyntheticRate Result

Average of Other Students’ PhotosyntheticRate

Results

N =(number of data averaged)

Data Table 4: Observationof pH Change in the Oxygen Cycle

Contents of

Respirometer

Initial

Color

T0, minutes

Final

Color

T1,minutes

Total timefor color change,

T1– T0,minutes

Elodea,

Bromothymol blue

solution

Elodea, Bromothymol blue solutionin foil

Data Table 5: Comparison of PhotosyntheticRate

My Result: Total timefor color change,

T1– T0,minutes

Average of Other Students’ Results: Total timefor color change,

T1– T0,minutes

N =(number of data averaged)

Elodea, Bromothymol blue solution

Elodea, Bromothymol blue solutionin Foil

Exercise 1: Chlorophyll Pigments

Results

Rf = distance to top of pigment in mm ÷ distance to top of solvent front.

Rf Average = average of other students’ Rf values, if available.

1. Rfvaluesarecalculatedratios ofhowfaramoleculemovedupthepaperchromatographas comparedtothelengthofthesolventfront.Thesevaluesaretypicallyequivalentformultiple trials.Calculate your Rf values based on your paper strip results, and record them inTable 1. The Rf value of the solvent front will always = 1.0, since Rf is a ratio.

2. Construct a stacked bar graph to demonstrate how the Rf value and the chlorophyll pigment are related.They-axiswillrepresenttheRfscalefrom0.0to1.0.Onthebargraph,labelthe calculated Rf with the name of the associated chlorophyll pigment. When complete, the bar graphshouldclosely resembletheactualchromatograph.Include astackedbargraphforyour results plusanother stacked bar graphnext to your graphwith your classmates’ averaged values.

Questions:

A. Identifytheareasofpigmentsthatyouobserveonthefilterpaper.Aretheylocatedinthe order that you expected?

If not, why not?

.jpg”>B. Compareyourpaperstripresultstotheresultsoftheradicchiopaperstripsbelow.Arethe same pigments present in radicchio leaves?

If not, which chlorophyll pigments are missing?

How might you have guessed that this might be the case?

Example of Results Obtained from Radicchio

.jpg”>Paper Chromatograph

Radicchio Paper Chromatograph, dried and marked in preparationfor Chlorophyll Pigment Rf determinations

.jpg”>

Discussion

A. Was the initialhypothesis supported or refuted? Explain.

B. If you do not see separate bands of color on the filterpaper, what might you conclude?

C. What might explain why the separationof the colors occurred?

D. Howdoyourvaluescomparetoyourclassmates’valuesforthesamepigmentsonTable1and in your graph? If they are not similar, what may be the reason?

Exercise2:ConversionofLightEnergytoFoodby

Plants

Questions

A. What molecule was produced by the Elodea while it was exposed to light?

B. Which organelle(s) in the plant cell is responsible for this reaction?

C. From where was this molecule derived?

D. What was the purpose of the light?

E. What molecule was produced by the Elodea while it was wrapped in aluminum foil? F. Which organelle was responsible for this reaction?

G. Setupatablesimilar toDataTable3:ComparisonofPhotosynthieticRateintheLabReport Assistantsection. CompareyourRateofPhotosynthesistotheaverageratesreportedbyother students in Table 3, if possible. How similar was your result to theirs?

H. Nameatleastthreeexperimentalvariables thatcouldexplainwhyyouroutcomemightvary from that of other students or from your own, if you repeated the experiment.