Energetic Metabolism

1
Energetic Metabolism

• Observing the Effects of Respiration and
  Photosynthesis

2
InterconnectionsPhotosynthesis Respiration
3
Chemical Equations

• Aerobic RespirationC6H12O6 6O2 ? 6CO2 6H2O
  energy
• Photosynthesis 6CO2 6H2O light energy ?
  C6H12O6 6O2

4
Metabolic Rate

• Speed of aerobic respiration in an organism (use
  of O2)
• Measured in Calories
• unit of energy
• amount of heat required to increase temperature
  of 1 kg of H2O by 1oC
• 1 liter of O2 consumption 4.825 Calories
• convert to ml O2/gram/hour to correct for
  different animal sizes

5
Factors Affecting Metabolic Rate

• Body Size

Hypothesis Do small mice have higher metabolic
rates than large mice?
6
Factors Affecting Metabolic Rate

• Body Temperature

7
Factors Affecting Metabolic Rate

• Gender
• Age
• Surface Area
• Body Composition
• Activity, including exercise
• Hormonal influences
• Note Only energy demand increases metabolic
  rate. Having more oxygen and/or glucose available
  does not speed up metabolism.

8
Using the Respirometer
Allow drop to start moving. Measure time it
takes to move by a specific volume of air.
If liquid enters jar, wipe your mouse dry.
Leave cork OUT except when makingmeasurements.
9
Calculations

• Suppose the average of 5 measurements is
• 0.5 ml O2 consumed in 30 seconds
• by 20 gram mouse
• Calculation of ml O2/gram/day

0.5 ml30 sec
x 60 sec 1 min
x 60 min 1 hour
x 24 hours 1 day
x 1 weight in grams
x 1 20 grams
72 ml O2/gram/day
10
Graphing Scatter Plot
Metabolic Rate(ml O2/gram/day)
Body Weight (grams)
Plot each mouses rate as one data point.
11
Photosynthesis Experiment
Hypotheses Will the rate of
photosynthesis be increased by 1. increased
light energy? 2. increased CO2
availability?
12
Tube Composition for Photosynthesis Experiments
Place tubes 20 cm from light source.Wait 5 min,
count bubbles for 5 min. Repeat at 15 cm and 10
cm from source.
13
Graphing Photosynthesis Data
Rate of Photosynthesis(Bubbles per 5 minutes)
Amount of Light Energy
14
CLEAN UP!

• Put your mouse back in its ORIGINAL container
• Clean and dry your respirometer.
• Leave clean test tubes inverted in the rack at
  your station
• Discard soda lime packets and elodea cuttings
  into the trash
• Make sure the sinks stay clean

15
Worksheet

• Complete pages 61-64 from lab manual
• Be sure your instructor checks your completed
  worksheet before you leave the lab