Enzymes

EnzymesOProteinOOnly act on certain substances called substrates

FunctionsOIncreases the rate at which molecules in the body are built or broken down

OThey are catalysts; They speed up reactions

OEven though enzymes speed up reactions, they are NOT changed during the reactionOSo enzymes are

reusable

FunctionsOPlay roles in other parts of the body OMyosin: important in muscle contraction

Enzymes at Work

1. An enzyme and a substrate are in the same area.

2. The enzyme grabs on to the substrate at a special area called the active site.

Enzymes at Work3. A process called catalysis happens. Catalysis is when the substrate is changed.

4. The enzyme lets go, and returns to normal, ready to work on another molecule of substrate. The substrate is no longer the same. It is now called the product

Enzyme VideoO http://highered.mcgraw-hill.com/sites

/0072495855/student_view0/chapter2/animation__how_enzymes_work.html

Factors that Affect EnzymesOTemperature-

as temperature increases, enzyme activity increasesO However

extremely high temperatures cause enzyme activity to stop

Factors that affect Enzymes

OpH-extremely high or low causes enzymes to stop working

Factors that affect EnzymesOInhibition

OCompetitive: enzyme is inhibited by an inactive substrate, or competitor, so called because it competes with the real substrate for the active site

OFeedback: an inhibitor binds to a different site of an enzyme, deactivating it

InhibitorsFeedback

GroupsOThe two main groups are:

OMetabolic: all chemical reactions that take place in a living cell

ODigestive: related to breaking down food for absorption

Digestive EnzymesOLipase: breaks down fatOProtease: breaks down proteinOCellulase: breaks down fiber; herbivores have

OAmylase: starts breaking down starches; starts chemical part of digestion

Digestive EnzymesOLactase: breaks down dairy

OSucrase: breaks down sugar

OMaltase: breaks down grainOAll of these enzymes are secreted by mucosal cells that line your small intestine

ImportanceOWithout enzymes our body would not function properly; there are several disorders related to lack of or improper enzymes

Importance-example

ODisease called PhenylketonuriaOBorn with a mutation that

leads to a mutation in the enzyme needed to break down the amino acid phenylalanine

O If left untreated this could lead to mental retardation