The 2 nd Law of Thermodynamics UNIT 2A

Transcription

1 Warm-Up #1 Ms. Romano really wants to help you build your critical thinking skills. Why do you think she cares so much about this aspect of your learning? How will critical thinking skills help you in your present and future life (outside of school)?

2 Warm-Up #2 State the name of the molecule required to move particles across the membrane from low concentration to high concentration, and state the name of the process.

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4 The 2 nd Law of Thermodynamics states entropy (disorder) increases over time, unless acted upon by external energy

5 The 2 nd Law of Thermodynamics states entropy (disorder) increases over time, unless acted upon by external energy Without external energy With external energy

6 The 2 nd Law of Thermodynamics states entropy (disorder) increases over time, unless acted upon by external energy Life depends on order (organization), and thus life depends on energy.

7 The 2 nd Law of Thermodynamics states entropy (disorder) increases over time, unless acted upon by external energy Life depends on order (organization), and thus life depends on energy. Free energy (ΔG) is the energy available for cells to use: the energy between chemical bonds The energy to hold this phosphorous atom to this oxygen atom.

8 The 2 nd Law of Thermodynamics states entropy (disorder) increases over time, unless acted upon by external energy Cells use free energy to form new chemical bonds (keep the order). Energy that does not go into forming new bonds gets lost as heat. Life depends on order (organization), and thus life depends on energy. Free energy (ΔG) is the energy available for cells to use: the energy between chemical bonds

9 CTQ #1 Explain how biological systems prevent entropy (disorder) from increasing, and describe how all consumed energy is lost in biological systems.

10 Cells use free energy to form new chemical bonds (keep the order). Energy that does not go into forming new bonds gets lost as heat. energy heat

11 Cells use free energy to form new chemical bonds (keep the order). Energy that does not go into forming new bonds gets lost as heat. ATP Exergonic reactions release free energy: ΔG is negative ADP + P

12 Cells use free energy to form new chemical bonds (keep the order). Energy that does not go into forming new bonds gets lost as heat. ADP + P Exergonic reactions release free energy: ΔG is negative Endergonic reactions absorb free energy: ΔG is positive ATP

13 Cells use free energy to form new chemical bonds (keep the order). Energy that does not go into forming new bonds gets lost as heat. Exergonic reactions release free energy: ΔG is negative Endergonic reactions absorb free energy: ΔG is positive Order is maintained in an organism because exergonic reactions are coupled to endergonic reactions.

14 Cells use free energy to form new chemical bonds (keep the order). Energy that does not go into forming new bonds gets lost as heat. Exergonic reactions release free energy: ΔG is negative Endergonic reactions absorb free energy: ΔG is positive Order is maintained in an organism because exergonic reactions are coupled to endergonic reactions. Solar energy must be constantly added to Earth: Solar energy à free energy (plants use sun to convert CO 2 into C 6 H 12 O 6 ) à heat

15 CTQ #2 Ignoring the effects of gravity, explain why all life on Earth would eventually die if the sun disappeared suddenly. Assuming colonization on the Moon or other extra-terrestrial objects is impossible, predict what kind of technology we would have to develop to keep humanity alive. (LO 2.2) (LO 2.3)

16 Closure Explain why an exergonic reaction is considered to have negative free energy.