Download Enzymes - Cloudfront.net

Add to your vocab sheet &
Correct Inv. 4.4
Proteins or Polypeptides

Examples


Uses


Nuts, meat (muscle), beans
Muscle, hair, nails, skin, enzymes
Made from Amino Acid chains (polypeptides)
that can be thousands of amino acids long


There are only 20 amino acids in nature!
-peptide
Enzymes





Large, complex proteins
Help speed up the rate of chemical reaction (catalyst)
–ase word ending (Lactase breaks down lactose)
Activity varies with pH and temperature changes
Can be denatured by extreme heat (shape is changed)



Eg. Think about an egg before and after it’s cooked. The egg
proteins are denatured as it cooks.
Can be reused over and over again
“Lock & Key” Model


Active Site: attracts and holds only molecules that have the right
shape
Substrate: molecule that is changed by the enzyme – must have
the right shape
Enzymes Video (click on it)
Example: Lactose Intolerance
Lactose is a sugar found in most milk
products
 Lactase is an enzyme that breaks down
lactose
 People who are missing lactase (can no
longer produce it) can’t eat lactose
unless they get artificial lactase.

Example: Lactose Intolerance
Investigation 4.4 Review
A monosaccharide turns Benedict’s
solution from blue to orange after
heating.
 A polysaccharide turns iodine from
amber/ yellow to dark blue/black without
heating.
 A disaccharide responds to neither
Benedict’s nor iodine.

Table 4-1 Results of Tests with Known Carbohydrates
Tube
Number
Carbohydrate
Type
Benedicts Color After
Heating
Iodine
Color
1
Monosaccharide
Orange
Amber/
Yellow
2
Disaccharide
Blue
Amber/
Yellow
3
Polysaccharide
Blue
Blue/ Black
Table 4-2 Results of Tests with Unknown Carbohydrates
Carbohydrate
Hypothesis
(Mono-,
Di-, or
Poly-)
Benedict’s
Color
After
Heating
Iodine
Color
Type of
Carbohydrate
(after testing)
Honey
Orange
Amber/
Yellow
Mono – (fructose &
glucose)
Oats
Blue
Blue/ Black Poly- (starch)
Table Sugar
Blue
Amber/
Yellow
Di- (sucrose)
Apple Juice
Orange
Amber/
Yellow
Mono- (fructose)
Powdered
Sugar
Blue
Amber/
Yellow
Di- (sucrose)
Maple Syrup
Yellow/
green
Amber/
Yellow
Mono- (fructose)some
Di- (sucrose)
Investigation 4.5

You’ll be using the same testing methods as in
lab 4.4 however you’ll do the lab in 3 Parts
1.
2.
3.

Part A: Properties of Starch
Part B: Properties of Salivary Amylase
(enzyme present in saliva – yes someone will be
spitting, discreetly into a test tube!)
Part C: Properties of Starch Mixed with Salivary
Amylase
At each Part you’ll test with both Benedict’s (and
heat) and iodine (no heat) and record your data.
SAFETY!
No eating or drinking during the lab!
 Iodine and Benedict’s can stain and are
both toxic!
 Wear aprons and goggles if you
choose.
 If you are the generous  saliva donor,
you will be the only one to handle, and
wash your test tubes!

Set up Part C – 1st! (it needs to sit for 15
minutes minimum!)
 READ the background info to help you
with the DQ and Analysis Questions
 Quiz on both labs (open notes/open lab)
Thursday!
