# Final Exam Study Guide

## Supplement

1.     If the cycling provides heat to warm the insect, estimate the time required for a bee to raise its muscle temperature from 20.0 °C to 30.0 °C if the substrate cycling takes place at an average rate of 20.0 micromoles/min/g of muscle and all of the heat generated remains in the flight muscle.

• Assumptions:
• 1 ATP is hydrolyzed/turn of cycle
• All hydrolysis energy of ATP goes to heat
• GATP hydrolysis = 30.0 kJ*mol-1
• the heat capacity of bee muscle is the same as that for water = 1.00 cal*g-1*°C-1 = 4.184 J*g-1*°C-1
• Calculation
• First calculate the energy released for each turn of the cycle:

(20.0 x 10-6 mol*min-1*g-1)*(30.0 x 103 J*mol-1)

= 0.600 J*min-1*g-1

• Next calculate the energy required:

(30.0 °C - 20.0°C)*(4.184 J*°C-1*g-1)

= 41.84 J*g-1

• Finally, dividing the total energy required by the energy released/cycle give the time:

(41.84 J*3-1) / (0.600 J*min-1*g-1)

= 69.73 min

= 69.7 min

2.     Try a second, perhaps more realistic calculation, by assuming a cycling rate of 20 micromoles/min/g of muscle and an aerobic glycolytic rate of 16 micromoles/min/ g of tissue.

3.     Assumptions:

• 1 ATP is hydrolyzed/turn of cycle
• All hydrolysis energy of ATP goes to heat
• all of the heat generated remains in the flight muscle (the bee is perfectly insulated)
• GATP hydrolysis = 30.0 kJ*mol-1
• the heat capacity of bee muscle is the same as that for water = 1.00 cal*g-1*°C-1 = 4.184 J*g-1*°C-1
• For each glucose going through glycolysis the bee will generate 30 ATP (not 32, since bee flight muscle uses the glycerol-P shuttle)
• All ATP's generated in glycolysis will be hydrolyzed to yield heat (probably via muscle contractions due to shivering)

4.     Calculation

• First calculate the energy released/time interval:

Energy from cycle + energy from glycolysis =

(20.0 x 10-6 mol*min-1*g-1)*(30.0 x 103 J*mol-1) + (16.0 x 10-6 mol*min-1*g-1)*(30 ATP)*(30.0 x 103 J*mol-1)

= 0.600 J*min-1*g-1 + 14.4 J*min-1*g-1

= 15.0 J*min-1*g-1

• Next calculate the energy required:

(30.0 °C - 20.0°C)*(4.184 J*°C-1*g-1)

= 41.84 J*mol-1

• Finally, dividing the total energy required by the energy released/cycle give the time:

(41.84 J*mol-1) / (15.0 J*min-1*g-1)

• = 2.79 min

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