Biology 1- Enzymes

Chapter 2, Section 4

Enzymes are Biological *Catalysts

Catalysts speed up the rate of the reaction.

Catalysts lower the energy input required for a chemical reaction to happen

Catalysts remain unchanged at the end of the reaction

Enzymes

Enzymes control chemical reactions that take place in the cytoplasm.

http://programs.northlandcollege.edu/biology/Biology1111/animations/enzyme.html

*Catalase in an example of an enzyme made by living cells

*Catalase

The enzyme catalase breaks down the waste substance hydrogen peroxide into water and oxygen.

Copy the Complete Equation Below into your notes:

Hydrogen peroxide oxygen +water

(enzyme)

catalase

(substrate)

(products)

Enzyme activity

Enzyme activity is affected by Temperature and pH.

**Optimum Condition

Enzymes function best or are most active in specific conditions known as optimum conditions.

Optimum temperature for most enzymes is around 40 degrees C.

Enzymes denature at high temperatures (which means the enzymes are destroyed). This causes the reaction rate to fall rapidly.

Degradation reaction

Substrate

Enzyme

Product Memory

Hydrogen peroxide

Catalase

Oxygen and water

HPCOW

Starch Amylase Maltose “SAM”Maltose Maltase GlucoseProtein Pepsin PeptidesPeptides Proteas

eAmino acids

Fats Lipase Fatty Acids and Glycerol

**Properties of enzymes**

•Speed up reactions.•Are specific for certain substrates. •Not used up during the reaction (unchanged during reaction) •Require optimum conditions at which they work best.•At high temperature they become denatured (destroyed)•Enzymes are Globular Proteins that catalyze chemical reactions in living organisms.

Why do we need enzymes?

WRITE THIS OUT: Enzymes help cells maintain homeostasis

Reactions to slow to maintain life w/o enzymes.Can’t increase temperatures/pressure in cells (would be fatal)

- The enzyme binds to the substrate by it’s Active site.

Making reactions go faster

Increasing the temp makes molecules move faster Biological systems are very sensitive to temperature

changes. Enzymes can increase the rate of reactions without

increasing the temp They do this by Lowering the acivation energy. Enzymes create a new reaction pathway a “Short-

cut” Enzyme controlled reactions proceed 198 to 1011

times faster

The Substrates of an enzyme are the reactants that are activated by the enzyme.

Enzyme are specific to their substrates.The specificity is determined by the

active site.

Lock and Key

http://www.lewport.wnyric.org/jwanamaker/animations/Enzyme%20activity.html

Lock and Key Hypothesis

Fit between the substrate & the Active site is exact Like a key fits into a lock very precisely The Enzyme is like the key and the substrate is like

the lock Temporary structure called the enzyme-substrate

complex is formed Products have a different shape from the substrate Once formed, they are released from the active site Leaving it free to become attached to another

substance

ACTIVATION ENERGY

The minimum amount of energy needed to start the reaction, leading to formation of a high energy intermediate.

Degradation reactions

animation