Aim #20: How do enzymes control the rate of chemical reactions? Date: October 21, 2016 Aim #20: How do enzymes control the rate of chemical reactions? HW: Enzyme practice worksheet due Monday  Castle Learning due Tuesday Textbook HW due day of test! (Wednesday) Do Now: Clear your desks and take out a pen or pencil.

1) What are enzymes made up of? **enzymes are never used up or changed so they can be reused** Enzymes are made up of proteins AKA: Organic Catalysts Organic- contains carbon and hydrogen Catalysts- affect the rate of chemical reactions

2) How do enzymes function? Substrate- molecule(s) that an enzyme works on Active Site- pocket or groove where the chemical reaction takes place (where substrate meets enzyme) Enzyme-Substrate Complex: substrate temporarily binds to active site (held in by hydrogen or ionic bonds)

Short Video: How Enzymes Work McGraw-Hill http://highered.mcgraw- hill.com/sites/0072495855/student_view0/chapter2/animation__ how_enzymes_work.html

3) What are cofactors? Small molecules that bind with enzymes and are necessary for enzyme function Inorganic- metal atoms Organic- coenzymes (most vitamins)

4) What is the Lock and Key Hypothesis? Enzymes are specific and will only work on one type of substrate

5) How are enzymes named? Enzymes often end in “-ase” Lipase- works on lipids Protease- works on proteins Maltase- works on maltose

6) What is activation energy (Ea)? The amount of energy need to START a chemical reaction How do enzymes affect the activation energy of a chemical reaction? Enzymes lower the activation energy needed for a reaction to take place

7) What factors affect enzyme reactions? Temperature- As the temperature increases, the rate of reactions increases then decreases. Optimum Temperature- the temperature at which the enzyme works best 98. 6 degrees Fahrenheit or 37 degrees Celsius Denature- high temperature will change the shape of the enzyme so it does not fit anymore

7) What factors affect enzyme reactions? pH- depends on where enzyme is working in the body Amylase- breaks down starch in the mouth (pH= 6.2 to 7) Pepsin- breaks down protein in the stomach (pH= 1.5-2.2) Trypsin- breaks down protein in the small intestines (pH= 8)

7) What factors affect enzyme reactions? c) Enzyme concentration- as more enzymes are added, enzyme action increases and then eventually levels off

7) What factors affect enzyme reactions? d) Substrate concentration- as more substrate is added, enzyme action increases and eventually levels off

Let’s Review! What is an enzyme? What are enzymes made of? What is a substrate? Can an enzyme work on any substance? What letters do enzymes often end in? What factors affect the rate of enzyme action?

Which chemical is classified as an enzyme? galactose lipid protease manganese dioxide

In enzyme controlled reactions, the role of certain vitamins such as niacin is to act as an enzyme a substrate a coenzyme a polypeptide