Warm Up Base your answer to this question on the diagram below, which represents stages in the digestion of a starch, and on your knowledge of biology. The products would most likely contain A. simple sugars. C. amino acids. B. fats. D. minerals.

Enzymes: “Helper” Protein molecules 2009-2010

Chemical Reactions A. When bonds are broken and reformed to make different substances. EX: Reactants Products C6H12O6 + 6O2 6CO2 + 6H2O Remember, energy is stored in the bonds of the compounds. Reactants are also called raw materials – They need to know this term. Have them tell you the reactants and products of the above equation.

Chemical reactions of life Processes of life A. building molecules = synthesis B. breaking down molecules = digestion + +

What is needed to start a reaction? Energy absorbed Activation energy Reactant Products Energy released Activation Energy: energy required to get a reaction started Point out the high amount of energy needed with reaction in graph. The activation energy on the graph comes in when you click the mouse – the purpose is to get the answer from them first. – Remember enzyme demo

Nothing works without enzymes! How important are enzymes? A. all chemical reactions in living organisms require enzymes to work building molecules = synthesis enzymes breaking down molecules = digestive enzymes + enzyme We can’t live without enzymes! + enzyme

B. enzymes speed up reactions = catalysts

C. Digestion Reaction Is the breakdown of a complex molecule into simpler substances These reactions RELEASE energy Enzyme Enzyme Enzyme Enzyme

D. Synthesis Reaction The combining of simple molecules into a more complex ones This reaction builds new molecules and/or STORES energy Reactants Products Enzyme Enzyme Enzyme

Examples Synthesis enzyme + Digestion enzyme +

Enzymes are proteins & each enzyme is the specific helper to a specific reaction. A. Each enzyme needs to be the right shape for the job B. Enzymes are named for the reaction they help i. sucrase breaks down sucrose ii. proteases breakdown proteins iii. lipases breakdown lipids iv. DNA polymerase builds DNA Oh, I get it! They end in -ase

Enzymes aren’t used up **Enzymes are NOT changed by the reaction A. used only temporarily B. re-used again for the same reaction with other molecules C. very little enzyme needed to help in many reactions substrate product active site enzyme

It’s shape that matters! Lock & Key Theory A. shape of protein allows enzyme & substrate to fit B. specific enzyme for each specific reaction Substrate Enzyme Products

What Affects Enzyme Activity Temperature: pH: Temperature: all enzymes have an optimal temp they work best at pH: acidity/alkalinity can increase or decrease the function of an enzyme Concentration: Increasing the concentration of the enzyme can increase the rate of the chemical reaction 3 7 5 9 11 13 Neutral Battery Acid Bleach Blood (7.5)

Temperature & Effect on Rates of Enzyme Activity A. Optimum (best) temperature i. greatest number of collisions between enzyme & substrate ii. human enzymes = 35°- 40°C (body temp = 37°C) B. Raise temperature (boiling) i. denature protein = unfold = lose shape C. Lower temperature i. molecules move slower ii. fewer collisions between enzyme & substrate

Temperature human enzymes Reaction Rate Temperature ( ̊ C) 37° What’s happening here?! 37° Reaction Rate Temperature ( ̊ C)

pH & Effect on Rates of Enzyme Activity A. changes in pH = changes protein shape B. most human enzymes work best at pH 6-8 i. depends on where in body ii. pepsin (stomach) = pH 3 iii. trypsin (small intestines) = pH 8

pH stomach pepsin intestines trypsin reaction rate pH 1 2 3 4 5 6 7 8 What’s happening here?! reaction rate 1 2 3 4 5 6 7 8 9 10 11 12 13 14 pH

Denature A. When enzymes are exposed to extreme pH or high temperatures, they can denature B. When denatured, an enzyme will no longer function, due to a change in enzyme structure C. This is why running high fevers for extended time is cause for concern

Enzyme vocabulary review Protein; speeds up chemical reactions by lowering activation energy Substrate molecule that enzymes work on Products what the enzyme helps produce from the reaction Active site part of enzyme that substrate molecule fits into