1. A. What is the volume of the earth's oceans in liters?
B. How many moles of water are there in the earth's oceans?
C. How many molecules of water are there in the earth's oceans?
D. How much energy in Joules would it take to raise the ambient temperature 1oC?
2. Why do heart and skeletal muscle prefer to use fatty acids rather than glucose as an energy source?
3. You are measuring the activity of the enzyme protein tyrosine phosphatase (PTP) using fluorescein diphosphate FDP) as substrate in the presence and absence of the inhibitor vanadate. From the data calculate Vmax and Km in the presence and absence of vanadate. What type of inhibitor is vanadate?
Show all work.
| [FDP] (mM) | v without vanadate (nmoles/sec) | v with vanadate (nmoles/sec) |
|---|---|---|
| 6.67 | 5.7 | 0.71 |
| 10 | 8.3 | 1.06 |
| 20 | 12.5 | 2.04 |
| 40 | 16.7 | 3.7 |
| 100 | 22.2 | 8.0 |
| 200 | 25.4 | 12.5 |
1. volume of water in the oceans = 1.37x10^9 Km^3
1 Km^3 = 1x10^9 m^3
1 m^3 = 1x10^6 cm^3
1 liter = 1000 ml = 1000 ccs = 1000 cm^3
1A.1.37x10^21 liters
1B. 7.61x10^22 moles
1C. 4.57x10^46 molecules
1D. 5.73x10^24 J (pure), 5.47x10^24 J (salt water)
2. Muscle, like all tissues, is oxidizing carbohydrates and fatty acids to CO2 and H2O. If you examine glucose, each C is already half oxidized (has one O attached), whereas fatty acids are fully reduced (-CH2-). Therefore more energy is supplied by fatty acids than glucose, that is more ATP is produced by the oxidation of fatty acids than glucose.
3. control: y = 0.91x + 0.035
Vm = 28.6 nmoles/sec, Km = 26uM
vanadate: y = 9.13x + 0.035
Vm = 28.6 nmoles/sec, Km = 237 uM
Vm is the same but Km is increased: competitive inhibition of PTP by vanadate.