Download Proteins and Enzymes

Proteins and Enzymes
October 28, 2013
Welcome! 10/28/13
•  OBJECTIVE: Students will: (1)Test the effectiveness of enzymes in a
digestion reaction. (2)Explain the importance of proteins and enzymes in
the body
• 
CATALYST:
1. Which statement describes the major role of lipids within a cell?
A. They cause DNA to replicate.
B. They move RNA in the cytoplasm.
C. They catalyze chemical reactions in the cell cytoplasm.
D. They are the main structural components of membranes.
2. The cell wall of a plant helps the plant cell maintain its shape. What is the
main structural component of the cell wall of a plant?
A. Lipid
B. cellulose
C. amino acid
D. nucleic acid
3.What molecules control the reaction rate of photosynthesis?
A. Sugars
B. enzymes
C. fatty acids
D. nucleic acids
• 
HOMEWORK/REMINDERS
•  1st Quarter ENDS TODAY
QUIZ 1.3 Tomorrow
HW 1.4 DUE Wednesday
Catalyst Review
1. Which statement describes the major role of lipids within a
cell?
A. They cause DNA to replicate.
B. They move RNA in the cytoplasm.
C. They catalyze chemical reactions in the cell cytoplasm.
D. They are the main structural components of membranes.
2. The cell wall of a plant helps the plant cell maintain its
shape. What is the main structural component of the cell wall
of a plant?
A. Lipid
B. cellulose
C. amino acid
D. nucleic acid
3.What molecules control the reaction rate of photosynthesis?
A. Sugars
B. enzymes
C. fatty acids
D. nucleic acids
Review
1.  What is a monomer?
Building blocks of larger molecules
2.  What are the monomers of proteins?
Amino Acids
3.  What is the function of proteins?
Runs cell reactions
Gives structure
Ex. ENZYMES
Review Questions
What do we know about enzymes?
•  Function: speeds up chemical reactions
in cells
•  Names of enzymes often end in –ase
•  A type of protein (macromolecule),
built of amino acids
Pre-Lab Questions
•  Answer the two pre-lab HSA questions.
•  Fill in the box for “First Answer”
•  We will return to these questions after the lab
Mini Enzyme Experiment
Background: Amylase is an enzyme found in your
saliva. Its job is to begin breaking down amylose
(sugar) found in starch molecules from your food into a
simpler sugar molecule: glucose. Remember that starch
is a polysacccharide and glucose is a monosaccharide.
In this lab, you will explore two things:
1) Does amylase speed up starch digestion?
2) Does amylase break down starch into glucose
(sugar) molecules?
Part 1: Does amylase speed up
starch digestion?
1.  Hypothesis : If I put a chip in my mouth, then it will
break down (faster/slower) than in plain water.
2.  Place one half chip/cracker in a test tube with 25 mL of
water. What lab equipment will you use to measure the
water?
3.  Place the other half of the chip/cracker on your tongue.
Start the timer. Write down the time when the potato chip/
cracker in your mouth is completely broken down (mushy and
tastes sugary). NO CHEWING! Check the chip/cracker in the
test tube every 2 minutes
Part 1: Does amylase speed up
starch digestion?
4.  What was your control in this experiment?
5.  Name 2 things you kept constant in the experiment:
CONCLUSION
What happened? Which chip/cracker broke down faster?
Why do you think that is?
How could you improve this experiment?
Part 2: Does amylase break
down starch into glucose?
Background information: Iodine is an indicator that
turns blue/black in the presence of starch. Benedict is
an indicator that turns orange/red in the presence of
glucose.
1.  Hypothesis A: If amylase breaks down starch to
glucose then the chip/cracker (will/will not) turn
blue/black in the beaker with saliva.
2.  Hypothesis B: If amylase breaks down starch to
glucose then the cracker (will/will not) turn
orange/red in the beaker with saliva.
Part 2: Does amylase break
down starch into glucose?
Table A: Starch Test
Contents of
Test Tubes
16 mL H20 +
1g corn starch
15 mL H20 +
1mL Saliva +
1g Corn
Starch
Iodine Test
(Color
Change)
Table B: Glucose Test
Contents of
Test Tubes
Piece of
cracker + 3mL
Benedicts
solution
Piece of
cracker + 3mL
of H20 + 5mL
of Benedicts
Benedicts Test
(Color
Change)
Part 2: Does amylase break
down starch into glucose?
Answer questions 3-5 to identify variables and
constants in the experiment. Make conclusion.
REVIEW:
•  Independent Variable—what the scientist
CHANGES in an experiment
•  Dependent Variable—what the scientist
MEASURES in an experiment
•  Constants—things that stay the same
Extension
1.  What is the main type of macromolecules found in a
cracker?
2.  What are the building blocks of that macromolecules?
3.  Lactose is a sugar found in milk. What enzyme do you
think breaks down lactose? Remember amylase breaks
down amylose
4.  Individuals who are lactose intolerant cannot digest milk
properly. Based on the information from this lab activity,
what can you conclude about their body that would
make it impossible for them to break down lactose
products?
Notes
•  Human saliva contains an enzyme called amylase
•  Enzymes are catalysts—they speed up reactions
•  Cellular processes would be too slow without enzymes
•  Enzymes bind to a substrate to produce a product
•  Enzyme function is affected by abiotic factors such
as: temperature and pH
•  These abiotic factors could cause enzymes to
denature, and then they will not function.
Macromolecules and Nutrition
Review
•  Complete the concept map using the word bank
•  Read then 2 paragraphs about amylase and answer
the 3 questions at the end.
Exit Slip
•  Go back to the 2 multiple choice questions
on the front. Re-answer the questions. If
you changed your answer, explain why.