Transcript Amylase LAb - WordPress.com

Bellwork: Tue. Sept. 15, 2015 read the following
Enzyme Amylase Reaction on Starch
Introduction: Today you’ll observe the action of the enzyme amylase on
starch. Amylase changes starch into a simpler form the sugar maltose, which
is soluble in water. Amylase is in our saliva, and begins to act on starchy food
while in our mouth.
Exposure to heat, extreme pH (acid or base) & an inorganic salt or
organic solvent (e.g., alcohol) denature proteins (like an egg white
cooking) Enzymes, including amylase, are proteins. If denatured, an enzyme
can no longer act as a catalyst for the reaction.
Benedict's solution, a test reagent that reacts positively with simple reducing
sugars like maltose, will not react with starch. A positive test forms a
brownish-red cuprous oxide precipitate. A weaker positive test will be
yellow to orange.
1. What enzyme is in your saliva?_____________________
2. What three things will denature a protein ________________,
________________, ____________________
3. Benedict’s solution turns ___________________ in the
presence of the “sugar” ____________________ in this lab
Amylase is an enzyme in human
saliva that catalyses the
breakdown of starch into sugar –
maltose – two linked glucose
molecules.
The chemical process of digestion
begins the moment we put food
into our mouth.
Food that contains a lot of starch
but very little sugar (potatoes and
rice) taste slightly sweet as they
are chewed because amylase
turns some of their starch into
sugar in our mouth!
Copyright Pearson Prentice Hall
PRE-LAB
I’m adding 1g (approx ¼ tsp) of
cornstarch to a beaker containing 100ml
of cold distilled water. While stirring
frequently, heat the mixture just until it
begins to boil. Allow to cool.
PRE-LAB: large batch Add
10g of cornstarch to a
beaker containing 1000ml
of cold distilled water.
While stirring frequently,
heat the mixture just until
it begins to boil. Allow to
cool.
1. "Spit" between 1 to 2 mL of
saliva into each test tube (A,B,C)
vinegar
2. Into tube A, add 2 mL of vinegar. Into
tubes B and C, add 2 mL of distilled
water. Thump the tubes to mix.
3. Place Test tube B in boiling
water 5 min.
4. Cool test tube B
distilled
water
5. Add 5 mL of the starch solution to each tube
and thump to mix. Allow the tubes to sit for 10
minutes, occasionally thumping the tubes to mix.
6. Add 2-3 mL of Benedict's solution to each
tube and thump to mix. Place the tubes in the
hot water bath. The reaction takes several
minutes to begin.
Copyright Pearson Prentice Hall
Bellwork: Wed Sept. 16, 2015
1. What is the function of an enzyme? _________________
2. Where does a substrate attach to an enzyme?____________ __________
3. If an enzyme is present in a reaction, less _____________ is needed to
get the reaction started.
4. What is a common suffix found at the end of most biological enzymes? _
________
5. Most enzymes are macromolecules called ________________.
6. Define denaturation of proteins:___________________________________
7. Name 3 things that can denature or unfold an enzyme. _________
______________________ ______________________
8. In this lab, what weak acid denatured the protein? _______________
9. What was the purpose of placing one test tube in a hot water bath?
_________________
10. What happens to enzymes in your body whenever you run a fever?
______________________ ______________________
______________________
Bellwork: Wed Sept. 16, 2014
1. What is the function of an enzyme? _________________
Speed up rate of reaction and lower activation energy
2. Where does a substrate attach to an enzyme?_________________
Active site
Activation energy
3. If an enzyme is present in a reaction, less ______________________
is
needed to get the reaction started.
4. What is a common suffix found at the end of most biological enzymes?
-ase
______________
5. Most enzymes are macromolecules called ________________.
protein
6. Define denaturation of proteins:__________________
When proteins lose structure by application of stress or compound
7. Name 3 things that can denature or unfold an enzyme. _________
1. strong acid or base 2. inorganic salt or organic solvent 3. heat
8. In this lab, what weak acid denatured the protein? _______________
vinegar
9. What was the purpose of placing one test tube in a hot water bath?
to_________________
denature the protein (enzyme – amylase)
10. What happens to enzymes in your body whenever you run a fever?
They are denatured - a virus is DNA or RNA and a protein
coat - so the virus is “killed”
Each protein has a specific, complex
shape. The substrates bind to a site on
the enzyme called the active site.
The active site and the substrates have
complementary shapes. The fit is so
precise that the active site and substrates
are often compared to a lock and key.
• http://highered.mcgrawhill.com/sites/0072943696/student_view0/chapter2/anim
ation__a_biochemical_pathway.html
Copyright Pearson Prentice Hall
Tube A: Starch + saliva treated with vinegar (acid)
1. Was the test positive or negative?__________________
2. What does this indicate?__________________________________
Tube B: Starch + saliva & water, treated in boiling water bath.
3. as the test positive or negative? ________________
4. What does this indicate?________________________________
Tube C: Starch + saliva
5. Was the test positive or negative?
_______________________
6. What does this indicate?
____________________________
Denaturation of Proteins:
When proteins lose structure by application of
stress or compound - reactions with:
1. a strong acid or base
2. an inorganic salt or organic solvent (e.g., alcohol)
3. heat
•http://highered.mcgrawhill.com/sites/0072943696/student_view0/chapter2/animation__protein_
denaturation.html
• Chemistry Review: due next Tuesday.
Why – I’m going to be gone Friday so I
can’t remind you if I were to make the test
Monday.
Copyright Pearson Prentice Hall
http://www.pearsonsuccessnet.com/snpap
p/iText/products/0-13-1811185/ch2/ch2_s4_0.html
Copyright Pearson Prentice Hall
Bellwork: Mon. Sept. 14, 2015
Cell notes 3
http://www.youtube.com/watch?v=E-_r3omrnxw
The function of an enzyme:
speed up chemical reactions in organisms
by lowering activation energy!
All enzymes are macromolecules called proteins
sugar
phospholipid
CHO
Veg. Oils, CHO (P)
fat
Meat
CHON
energy
monosaccharide
Fatty acid
& glycerol
energy
Build bones
& muscles
amino acids
http://www.youtube.com/watch?v=FxE8PSo9994
glucose
Unsaturated
fatty acid
amino acid
chains
A few hint for the crosswords:
Mass: quantity of matter
Orbital: region around the nucleus where
electrons are located
Aqueous: Solution in which water is the
solvent