1. Problem of the Day John’s father asked him to fertilize the lawn. Fertilizer consists of nitrogen, phosphorus and potassium compounds. John got the bag of fertilizer, put in in the spreader and applied it to the lawn. While he was fertilizing, his dad came out and said to make sure the setting on the spreader was correct. John consulted the bag and the correct spreader setting was “5.” He checked the spreader and it was set on “10,” meaning that John had been applying twice as much fertilizer as he needed. Is there a problem, and if so is there anything he could do about it?

2. Problem of the day: Brevetoxin is a produced by red tide organisms called Karenia brevis. People consume this toxin in contaminated shellfish from red tide occurrences. Brevetoxin prevents sodium ion channels in nerve cells from closing. How could this affect the nerve cells, and what kind of symptoms could result. It’s ok to use a book to research this.

3. The binding of brevetoxin to VSSCs produces three key effects: a lowering of the activation potential to more negative values, the persistent activation of the channel and therefore repetitive firing of nerves, and the inability to reverse this prolonged mean open state. This leads to a number of health problems in both humans and animals alike. The disruption of normal sodium channel function namely results in massive fish kills and the poisoning of marine mammals and other aquatic invertebrates, which in turn are a source of human health problems as well. For instance, pulmonary receptors associated with ligand-gated epithelial Na+ channels and cathepsin inhibition in macrophages have been reported to be effected by brevetoxin exposure.cathepsin

4. Chapter 8: An Introduction to Metabolism ______ You Must Know: Examples of endergonic and exergonic reactions Key role of ATP in energy coupling Enzymes work by lowering activation energy The catalytic cycle of an enzyme that results in production of a final product Factors that influence enzyme activity

5. Metabolism/Bioenergetics Metabolism: The totality of an organism’s chemical processes; managing the material and energy resources of the cell Catabolic pathways: degradative process such as cellular respiration; releases energy Anabolic pathways: building process such as protein synthesis; photosynthesis; consumes energy

6. What is free energy? Gibbs free energy Thermodynamics~ study of E transformations 1st Law: conservation of energy; E transferred/transformed, not created/destroyed1st Law: conservation of energy; E transferred/transformed, not created/destroyed 2nd Law: transformations increase entropy (disorder, randomness)

7. Essential Knowledge 2.A.1 All living systems require a constant input of free energy Life requires a highly ordered system. –Order is maintained by constant free energy input into the system –Loss of order or free energy flow results in death. –Increased disorder and entropy are offset by biological processes that maintain or increase order

8. Essential Knowledge 2.A.1 cont’d. Living systems do not violate the 2 nd law of thermodynamics: ∆G is a symbol for a change in free energy. For example, cellular respiration releases the energy in glucose by a ∆G of -686 kcal/mol. Order is maintained by coupling cellular processes that increase entropy (-∆G) with those that decrease entropy (+∆G). Energy input must exceed free energy lost to entropy. Exergonic reactions are coupled with endergonic reactions Life is an open system

9. Free energy-Know these graphs!! Free energy: portion of system’s E that can perform work (at a constant T) Exergonic reaction: net release of free E to surroundings Endergonic reaction: absorbs free E from surroundings

10. Sample Test Question The graph shows the effect of an enzyme on activation energy. Determine the Gibbs free energy change (∆ G) for the reaction. Express your answer to the nearest whole number. You would receive a sheet that has this formula: ∆G=∆H-T∆S Assume that each block represents 10 kcal/mole of energy. Answer: -70 kcal Energy (kcal/mole) time

11. Energy Coupling & ATP E coupling: use of exergonic process to drive an endergonic one (ATP) Adenosine triphosphate ATP tail: high negative charge ATP hydrolysis: release of free E by breaking off a phosphate Phosphorylation (phosphorylated intermediate)~ enzymes-storing energy by adding a phosphate.

12. Essential Knowledge 4.B.1 Competition and cooperation are important aspects of biological systems.

13. What are Enzymes? What are Enzymes? Catalysts-substance that can change the rate of a reaction without being altered in the process Enzymes-macromolecules (proteins or RNA) that are biological catalysts Activation energy-the amount of energy needed to start a chemical reaction Substrate-the reactant that an enzyme acts on Active site-part of the enzyme that binds to the substrate

14. Enzyme animation Enzyme animation

15. Enzymes-Know this graph too!!! Catalytic proteins: change the rate of reactions w/o being consumed Free E of activation (activation E): the E required to break bonds Substrate: enzyme reactant Active site: pocket or groove on enzyme that binds to substrate Induced fit model

16. Effects on Enzyme Activity Temperature pH Cofactors: inorganic, nonprotein helpers; ex.: zinc, iron, copper Coenzymes: organic helpers; ex.: vitamins Cofactors and coenzymes relate to a structural change that alters activity rate

17. Enzyme Inhibitors Irreversible (covalent); reversible (weak bonds) Competitive: competes for active site (reversible); mimics the substrate Noncompetitive: bind to another part of enzyme (allosteric site) altering its conformation (shape); poisons, antibiotics (sarin gas) Data will show different concentrations of product or substrate as a function of time

18. Regulation of Enzyme Activity Many enzyme regulators bind to an allosteric site, which is a specific binding site, but not the active site-this can either stimulate or inhibit enzyme activity The end product can switch off its pathway by binding to the allosteric site; this is feedback inhibition