Energy!

1. Energy! Big Idea #2: Energy is needed to do stuff.

2. Big Idea #2 • Biological Systems utilize free energy and molecular building blocks to grow, to reproduce and to maintain dynamic homeostasis

3. Essential Knowledge • 2A1: All living systems require constant input of free energy.

4. Energy • Ability to do something (i.e. move) • 2 general types: • Potential energy- stored energy • Kinetic energy – moving energy

7. Potential vs. Kinetic Energy • Resting objects • Nuclear • Hydroelectic (water behind a dam) • Food • Moving objects • Radiation (light particles/waves) • Thermal (heat) • Electrical (movement of electrons)

8. 1st Law of Thermodynamics • Energy cannot be created nor destroyed • May changefrom one form to another Ex: Solar Energy  Chemical Energy

9. 2nd Law of Thermodynamics • No rxn is 100% efficient  lose energy • Systems spontaneously increase entropy (disorder)

10. Entropy • Amount of energy in an unusable form – usually heat • Is always increasing b/c systems are always losing usable forms of energy

11. Biologically Speaking… Remember 10% Rule! • Living orgs require an energy input. • Ex: orgs must get energy from sun, deep thermal vents, or eating

12. Order and Organization Require Energy Things naturally break down – to keep them from breaking down or to put them together requires an input of energy

13. Energy Coupling • Processes that release energy are coupled to ones that require an input of energy • More energy must be released than is required

14. Example Do You Have Any Band Aids? • Flexing a muscle requires an energy input and breaking down food releases energy (ATP).

15. Exergonic Reactions • Release free energy • Provides energy for living processes

16. The Most Significant Exergonic Reaction ATP + H2O ADP + Pi + Energy

17. Making ATP is an Endergonic Reaction • Requires an input of energy • Made in cellular respiration

19. Uses of Free Energy • Maintain body temp (some organisms)/Internal temp regulation • Reproduction • Growth • Movement

20. Body Temp Regulation • Endothermy: Use heat released by metabolic reactions to keep a stable temp • Ex: Humans 98.6⁰

21. Body Temp Regulation • Ectothermy: Use external sources to try to maintain body temp. • Ex: snakes/reptiles

22. Reproduction • Requires a huge amount of energy  • Many species reproduce when energy is available • Ex: Spring plants reproduce

23. Growth • Extra free energy not needed for cellular processes (movement and reproduction) can be put to growth • Ex: extra calories become stored fat

24. Energy Deprivation RIP Tako  • Mass is broken down to provide energy • No energy input = death

25. Smaller Organisms Require More Food Per Body Mass • Smaller orgs have more surface area to volume  lose more heat… must replenish energy loss by eating more

26. The Trophic Levels • Energy goes up food chain • At every level energy is being lost due to entropy.

27. So…less energy available for high levels of food chain • Rarely enough energy to support more than 3-4 levels on a food chain

28. Energy on an Ecological Level • More energy available for a pop., more it will grow • Ex: rain forests

29. Energy Doesn’t Cycle!!!!!!