The green objects represent ________? Dashed line? Passive or Active transport?

1. The green objects represent ________? Dashed line? Passive or Active transport? Molecules in aqueous solution = solute Cell (or plasma) membrane Passive transport; Diffusion of solutes toward equilibrium

3. Diffusion of water Towards equilibrium High concentration of water to low concentration of water Osmosis

4. Osmoregulation = controlling water balance internally in relation to the outside environment • Isotonic: (iso = same) cell is in a solution of equal solute concentration • Hypotonic: (hypo = below) cell is in a solution of lower solutes • Hypertonic: (hyper = above) cell is in a solution of higher solutes

5. Purple objects represent ___? Left side passive or active? Right side passive or active transport? Transport proteins in plasma membrane Passive transport; high concentration to low Active transport; against concentration gradient Expend energy ATP

6. Capacity to do work Kinetic E energy in motion E.g. muscle contractions, heat, light, active transport Potential E stored energy E.g. object at rest atop hill, food, ATP Energy conversion; transform from one form to another Energy?

7. Laws of E transformation • 1st Law of thermodynamics • Energy conservation • E can be transferred or transformed • E cannot be created or destroyed e.g. sunlight to starch via photosynthesis

8. Laws of E transformation • 2nd Law of thermodynamics • E escape or transfer during conversions • e.g. heat released during muscle contractions is transferred to the environment • Cells convert potential E to cellular E • Organized starch or glucose molecules to ATP • E escape leads to disorder • Entropy = amount of disorder or chaos in a system

9. How to deal with Entropy & prevent total chaos? • Energy input • More E is required to replace the E that escapes • Plants absorb solar E (kinetic E) • Animals eat food (potential E) • chemical reactions in cells convert energy • http://www.youtube.com/watch?v=5KIhDVLbMeY

10. Two types of chemical reactions in regards to Energy flow Endergonic reactions & Exergonic reactions • Endergonic reaction • Net input of energy • Increasing potential E • Building carborhydrates • making bonds • e.g. plants photosynthesizing

11. Exergonic reaction • Chemical rxn that releases energy • Covalent bonds of reactants have more potential E than products • Breaking down carbohydrates • Potential E to ATP • Breaking bonds

12. ATP powers cellular work • Breaks bond via hydrolysis • Phosphorylation • Exergonic or Endergonic? • e.g. transfer of phosphate to motor protein causes contraction (muscle cells, flagella movement)

13. Enzymes • Proteins that change the rate of chemical reactions Many act as catalysts – speed up reactions…. How? • Lower the activation energy = energy required to initiate a chemical reaction • Carbohydrates are potential E to fuel the cells • Cells convert ATP; to power a reaction • Enzymes make it easier for that reaction to occur Cyclist resting atop the hill is potential E… he doesn’t start speeding down the hill until the final little push to get him over the last barrier • Enzymes are catalysts (the push)