P 34 Compare and Contrast: Endergonic vs Exergonic 9 October 2019 P 34 Compare and Contrast: Endergonic vs Exergonic P 35 Chemical Reactions

Chemical Reactions

Change one set of chemicals into another set of chemicals Chemical Reactions Change one set of chemicals into another set of chemicals

Chemical Reaction Reactants The “ingredients” Products The “cookies” The elements or compounds that go into a chemical reaction. The “ingredients” Products The elements or compounds produced by a chemical reaction. The “cookies”

2 Mg + O2 -----> 2 MgO + energy

Activation Energy The energy needed to start a reaction The “spark” that starts a reaction

Reactants Products

2 H2 + O2 2 H2O Chemical Reaction Reactants Products Hydrogen plus Oxygen Products 2 H2O Water react to form

Energy in Chemical Bonds Exergonic Releases energy Exothermic Breaking bonds releases energy Can occur spontaneously Endergonic Absorbs energy Endothermic Forming bonds absorbs energy

If a reaction in one direction releases energy, the reaction in the opposite direction absorbs energy.

Exergonic Chemical Reaction Reactants 2 H2 + O2 Hydrogen plus Oxygen Products 2 H2O Water react to form

Endergonic Chemical Reaction Reactants 2 H2O Water Products 2 H2 + O2 Hydrogen plus Oxygen can be separated into its components

IAN LHP Compare and Contrast: Endergonic vs Exergonic

9 October 2019 P. 36 Questions P. 51 #1-6 Questions P. 53 # 1-5 Analogy P. 37 Enzymes Read Text pp. 49-53

Catalyst A substance that accelerates the rate of a chemical reaction Lowers a reaction’s activation energy

Enzymes Proteins that act as biological catalysts Reduces activation energy Speed up reactions

Analogy Explain how enzyme activity works like a lock and key.

Catalyzed Reaction Reactants in enzyme catalyzed reaction are called substrates Substrates bind to active site, precise fit Form enzyme-substrate complex Allows reaction to take place with less energy or at a lower temperature Release and enzyme is free to start again

LHP 36 Read Text pp. 49-53 Questions P. 51 #1-6 Questions P. 53 # 1-5 Analogy Explain how enzyme activity works like a lock and key.