BELLRINGER

What were the 2 food-based chemical reactions we studied in yesterday’s experiment?

What are the proteins that speed up metabolic reactions called?

AGENDA

Collect LAB: Exploring Enzymes

NOTES: Enzymes Shape, Function, and Naming Factor’s that slow enzymes Activation Energy

ENZYMES & SUBSTRATES

Enzymes are proteins that catalyze (speed up) chemical reactions in the body

The molecules that are affected by enzymes are called substrates

Example: Amylase is an enzyme in saliva that breaks down starchy foods like bread and pasta. In this case, starch is the substrate of amylase.

SUMMARY OF ENZYME PROPERTIES

Shape: Enzymes are globular (balled up) proteins

Function: Enzymes work by temporarily bonding with substrate molecules

Reusable: A single enzyme can be used multiple times

Name: Enzymes are named for the substrates they affect

SHAPE OF ENZYMES Enzymes are long protein chains that are

“knotted up” like a ball of yarn. The surface of an enzyme has a small pocket

called the active site which is shaped to bind substrate molecules.

Enzyme

Active Site

Substrate

HOW ENZYMES WORK

Substrate molecules temporarily bond with the enzyme at the active site.

The enzyme bends the substrate in a way that either breaks the molecule apart or allows it to bond with another substrate

Once the reaction is complete the enzyme releases the products.

SUMMARIZE WHAT IS HAPPENING IN THE VIDEO CLIP . . .

ENZYMES ARE REUSABLE

An enzyme only bonds with the substrate it works on for a short time.

After the reaction is over, the enzyme returns to it’s original shape and is ready to work again.

A single enzyme can induce millions of reactions per second.

ENZYMATIC REACTION

substrate (sucrose) + enzyme (sucrase)

enzyme-substrate complex

and +sucrase

glucose fructose

products + enzyme

ENZYME NAMING

Enzymes are specific to only one substrate. Since each enzymes only works on one reaction,

they are named for the molecules they affect. To name an enzyme, simply add the ~ase

ending.

Examples Lactose sugar is broken down by the enzyme Lactase Sucrose is digested by the enzyme ______________

FACTORS THAT SLOW ENZYMES

Enzymes are only effective when their active site is in the proper shape.

Since enzymes are proteins, they can become denatured (unfolded) and will no longer work.

2 things will denature proteins Changes in pH Changes in Temperature

ACTIVATION ENERGY

Many chemical reactions need energy to begin.

This energy that starts a reaction is called the activation energy.

Examples: Photosynthesis requires activation energy

from the sun Wood will not start burning without initial

heat source

ACTIVATION ENERGY VIDEO CLIP

ENZYMES LOWER ACTIVATION ENERGY Enzymes speed reactions up by

reducing the amount of activation energy a reaction needs.

The activation energy is reduced because the molecules at the active site are held in positions that make reactions easier.