Energetic MetabolismEnergetic Metabolism

Observing the Effects of Observing the Effects of Respiration and Photosynthesis Respiration and Photosynthesis

Interconnections:Interconnections:Photosynthesis & RespirationPhotosynthesis & Respiration

Chemical EquationsChemical Equations

• Aerobic RespirationAerobic Respiration

CC66HH1212OO66 + 6O + 6O2 2 6CO 6CO22 + 6H + 6H22O + energyO + energy

• PhotosynthesisPhotosynthesis 6CO6CO22 + 6H + 6H22O + light energy O + light energy C C66HH1212OO66 + 6O + 6O22

Measure OMeasure O22 use use

Measure OMeasure O22 production production

Metabolic RateMetabolic Rate

• Speed of aerobic respiration in an Speed of aerobic respiration in an organism (use of Oorganism (use of O22))

• Measured in CaloriesMeasured in Calories– unit of energyunit of energy– amount of heat required to increase amount of heat required to increase

temperature of 1 kg of Htemperature of 1 kg of H22O by 1O by 1ooCC– 1 liter of O1 liter of O22 consumption = 4.825 Calories consumption = 4.825 Calories

• Our experiment measures metabolic rate asOur experiment measures metabolic rate asmL OmL O22/gram/day, which can be converted to /gram/day, which can be converted to caloriescalories

Factors Affecting Metabolic RateFactors Affecting Metabolic Rate• Body TemperatureBody Temperature

Hypotheses: Do plants or animals have a higher metabolic rate?Hypotheses: Do plants or animals have a higher metabolic rate?How do environmental temperatures influence metabolic rates?How do environmental temperatures influence metabolic rates?

Mealworms Mealworms are are

ectothermic ectothermic animalsanimals

Experimental Set UpExperimental Set Up

soda limesoda lime

cheeseclothcheesecloth

peaspeas

mealwormsmealworms

Pipettes for Pipettes for peas:peas:

1-mL at 151-mL at 15ooCC5-mL at 305-mL at 30ooCC

Pipettes for Pipettes for mealworms:mealworms:5-mL at both 5-mL at both 15 and 3015 and 30ooCC

Reading the Respirometer PipettesReading the Respirometer PipettesFor 1-mL pipetteFor 1-mL pipette0.1 mL between 0.1 mL between

numbers numbers 0.01 mL between 0.01 mL between

smallest linessmallest lines

1 mL1 mL

0.1 mL0.1 mL

For 5-mL pipetteFor 5-mL pipette1 mL between 1 mL between

numbers numbers 0.1 mL between 0.1 mL between

smallest linessmallest lines

CalculationsCalculations•Suppose the total amount of OSuppose the total amount of O22 consumed in 30 consumed in 30 minutes minutes by 15.6 grams of mealworms was 3.5 mL.by 15.6 grams of mealworms was 3.5 mL.

•Calculation of mL OCalculation of mL O22/gram/day/gram/day

3.5 mL3.5 mL30 min30 min

x x 60 min60 min 1 hour 1 hour

x x 24 hours24 hours 1 day 1 day

x x _____1___________1______ weight in gramsweight in grams

= 10.8 ml O= 10.8 ml O22/gram/day/gram/day

x x 1 1 = = 15.6 grams 15.6 grams

x x 24 hours24 hours 1 day 1 day

3.5 mL3.5 mL30 min30 min11

x x 60 min60 min 1 hour 1 hour

22

Graphing: HistogramGraphing: Histogram

Plot the class averages for pea and mealworm Plot the class averages for pea and mealworm metabolic rates at both temperatures.metabolic rates at both temperatures.

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

Metabolic Rate (mL

O2/gram/day)

15 30

Temperature (degrees C)

Peas

Mealworms

2.1 mL2.1 mLgram daygram day

More Calculations (see page 62)More Calculations (see page 62)

•Suppose the metabolic rate of your peas was Suppose the metabolic rate of your peas was 2.1 mL O2.1 mL O22/ gram/day/ gram/day

•Calculation of the calorie intake of a 150 pound Calculation of the calorie intake of a 150 pound student whose metabolic rate matches the peasstudent whose metabolic rate matches the peas

x x 4.825 calories4.825 calories 1000 mL 1000 mL

x x 68040 grams68040 grams

= 689.4 calories/day= 689.4 calories/day

150 x 453.6 =150 x 453.6 =68040 grams68040 grams

x x 4.825 calories4.825 calories 1000 mL 1000 mL

2.1 mL2.1 mLgram daygram day

x x 68040 grams68040 grams

Photosynthesis ExperimentPhotosynthesis Experiment

HypothesisHypothesisWill the rate of photosynthesis be Will the rate of photosynthesis be

increased by increased light energy? increased by increased light energy?

Experimental Set UpExperimental Set Up

SyringeSyringe

ElodeaElodea

bicarbonatebicarbonatesolutionsolution

1-mL pipette1-mL pipette

For 1-mL pipetteFor 1-mL pipette0.1 mL between 0.1 mL between

numbers numbers 0.01 mL between 0.01 mL between

smallest linessmallest lines

Graphing Photosynthesis DataGraphing Photosynthesis Data

Plot the oxygen produced for light at 50 cm Plot the oxygen produced for light at 50 cm and 25 cm for each timed reading.and 25 cm for each timed reading.

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

0 5 10 15 20 25

Time (minutes)

Ph

oto

syn

thet

ic R

ate

(mL

O2

pro

du

ced

)

25 cm

50 cm

Graphing Photosynthesis DataGraphing Photosynthesis Data

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

0 5 10 15 20 25

Time (minutes)

Ph

oto

syn

thet

ic R

ate

(mL

O2

pro

du

ced

)

25 cm

50 cm

Linear (50 cm)

Linear (25 cm)

Use separate lines to connect the sets of points.Use separate lines to connect the sets of points.

CLEAN UP!CLEAN UP!

• Return your mealworms, peas, and Return your mealworms, peas, and elodea to the appropriate containerselodea to the appropriate containers

• Put used soda lime in discard bottlePut used soda lime in discard bottle

• Clean and dry your respirometers.Clean and dry your respirometers.

• Discard cheesecloth into the trashDiscard cheesecloth into the trash

• Make sure the sinks stay cleanMake sure the sinks stay clean

Worksheet Worksheet

• Complete pages 59-62 from lab Complete pages 59-62 from lab manualmanual

• Be sure your instructor checks your Be sure your instructor checks your completed worksheet before you completed worksheet before you leave the lableave the lab